We read with great interest the article by Macerollo et al. entitled “Non-invasive intervention for motor signs of Parkinson’s Disease: the effect of vibratory stimuli.”[1] The authors evaluated the use of a wearable device called the "Emma Watch" that produces a constant vibratory stimulus (200 Hz) to the wrist with frequencies of 20 bpm or 60 bpm in terms of motor function of the arms of 16 patients with Parkinson’s disease (PD).[1] Motor performance was assessed through three different tasks: a nine-peg hole test, a STYAR tracing task, and a SPIRAL tracking test.[1] The authors found that patients with PD who used the device with 200 Hz peripheral vibration modulated by 60 bpm as they carried out these tasks performed better in terms of speed and precision.[1] The final conclusion was that vibrotactile stimulation can improve motor function in patients with PD.[1] It is important to comment that the authors did not discuss their results in terms of other studies in the literature, including one systematic review published in 2014 [2] and another with a meta-analysis published in 2020. [3] In these studies, vibratory stimulation in patients with PD was generally seen to yield positive results with regard to balance and gait. [2,3] From a historical point of view, the pioneering and seminal work of Jean-Martin Charcot, who used a vibrating chair to treat patients with PD, should also be noted.[4,5]
1. Macerollo A, Holz C, Cletheror D, et al. Non-invasiv...
We read with great interest the article by Macerollo et al. entitled “Non-invasive intervention for motor signs of Parkinson’s Disease: the effect of vibratory stimuli.”[1] The authors evaluated the use of a wearable device called the "Emma Watch" that produces a constant vibratory stimulus (200 Hz) to the wrist with frequencies of 20 bpm or 60 bpm in terms of motor function of the arms of 16 patients with Parkinson’s disease (PD).[1] Motor performance was assessed through three different tasks: a nine-peg hole test, a STYAR tracing task, and a SPIRAL tracking test.[1] The authors found that patients with PD who used the device with 200 Hz peripheral vibration modulated by 60 bpm as they carried out these tasks performed better in terms of speed and precision.[1] The final conclusion was that vibrotactile stimulation can improve motor function in patients with PD.[1] It is important to comment that the authors did not discuss their results in terms of other studies in the literature, including one systematic review published in 2014 [2] and another with a meta-analysis published in 2020. [3] In these studies, vibratory stimulation in patients with PD was generally seen to yield positive results with regard to balance and gait. [2,3] From a historical point of view, the pioneering and seminal work of Jean-Martin Charcot, who used a vibrating chair to treat patients with PD, should also be noted.[4,5]
1. Macerollo A, Holz C, Cletheror D, et al. Non-invasive intervention for motor signs of Parkinson’s Disease: the effect of vibratory stimuli. J Neurol Neurosurg Psychiatry 2020; September. Online ahead of print.
2. Sharififara S, Coronado RA, Romero S, Azari H, Thigpen M. The effects of whole body vibration on mobility and balance in Parkinson’s Disease: a systematic review. IJMS 2014; 39 (4): 318-326.
3. Marazzi S, Kiper P, Palmer K, Agostini M, Turolla A. Effects of vibratory stimulation on balance and gait in Parkinson’s Disease: a systematic review and meta-analysis. Eur J Phys Rehabil Med 2020; Jan 14. Doi: 10.23736/S1973-9087.20.06099. Online ahead of print.
4. Goetz CG. Jean-Martin Charcot and his vibratory chair for Parkinson Disease. Neurology 2009; 73 (6): 475-478.
5. Kapur SS, Stebbins G, Goetz CG. Vibration therapy for Parkinson’s Disease: Charcot´s studies revisited. J Parkinsons Dis 2012; 2 (1): 23-27.
In clinical practice, neuropathies are groups of disorders with curable, treatable, and non-treatable aetiologies, the later accounting for most of the cases.[1] Every newly identified disorder either on the basis of etiology or syndromic group responding to particular treatment brings hope for few more patients.
This study by Shin J Oh et al [2] brings hope for some patients who were previously either classified as axonal neuropathy of undetermined cause orin the evolutionary phase of a neurodegenerative diseases (such as anterior horn cell diseases). Thus, in the absence of any evidence, such patients usually remained deprived of any immunotherapies and succumbed to the progressive disease. Now with this piece of information, it can be inferred that all those patients presenting with chronic (more than 2 months), symmetrical or asymmetrical, proximal and distal weakness without any evidence of demyelination (i.e. axonal) on nerve conduction studies and without any known secondary causes of axonal polyneuropathy could qualify for immunotherapy when nerve biopsy or CSF protein > 55 mg/dl shows evidence of inflammation. Thus, chronic inflammatory polyneuropathy syndrome would be a more apt diagnosis with two variants: demyelinating (usual Chronic inflammatory demyelinating polyneuropathy, CIDP) and axonal, much like Guillain-Barre syndrome.
However, it can be noted that all the patients included in the study did not qualify for CIAP. There were six patients w...
In clinical practice, neuropathies are groups of disorders with curable, treatable, and non-treatable aetiologies, the later accounting for most of the cases.[1] Every newly identified disorder either on the basis of etiology or syndromic group responding to particular treatment brings hope for few more patients.
This study by Shin J Oh et al [2] brings hope for some patients who were previously either classified as axonal neuropathy of undetermined cause orin the evolutionary phase of a neurodegenerative diseases (such as anterior horn cell diseases). Thus, in the absence of any evidence, such patients usually remained deprived of any immunotherapies and succumbed to the progressive disease. Now with this piece of information, it can be inferred that all those patients presenting with chronic (more than 2 months), symmetrical or asymmetrical, proximal and distal weakness without any evidence of demyelination (i.e. axonal) on nerve conduction studies and without any known secondary causes of axonal polyneuropathy could qualify for immunotherapy when nerve biopsy or CSF protein > 55 mg/dl shows evidence of inflammation. Thus, chronic inflammatory polyneuropathy syndrome would be a more apt diagnosis with two variants: demyelinating (usual Chronic inflammatory demyelinating polyneuropathy, CIDP) and axonal, much like Guillain-Barre syndrome.
However, it can be noted that all the patients included in the study did not qualify for CIAP. There were six patients with secondary causes (mostly M-band associated) for whom, treatment of the primary cause is indicated just like the demyelinating counterpart (CIDP secondary to gammopathies). However, this study paves the way for use of immunotherapy in a selected group of patients and defines the inclusion criteria for further research and drug trials. Future prospective multicentre studies with the above inclusion criteria are warranted.
Reference:
1. Samuelsson K, Press R. Chronic axonal idiopathic polyneuropathy: is it really benign. Current Opinion in Neurology. 2020 Oct;33(5):562–567.
2. Oh SJ, Lu L, Alsharabati M, Morgan MB, King P. Chronic inflammatory axonal polyneuropathy. J Neurol Neurosurg Psychiatry. 2020 Nov 1;91(11):1175–80.
We would like to thank the author for pointing out the fact that a proper disease control in myasthenia gravis (MG) probably predicts a favourable outcome during SARS-CoV-2 infection.
MG exacerbation was only observed in one patient (case 1) treated successfully with immunoglobulins (IVIG) as described. No MG crisis was reported during this period in non-infected patients.
None of the four patients described in our case report received COVID-19 related treatment, namely antiviral and/or hydroxychloroquine. Case 4 received antibiotherapy for 5 days (azythromicine and tazobactam).
Regarding case 2, this patient presents with recurring symptoms of fever and shortness of breath since March 2020. In this regard a chest CT and repeated D-dimers were performed in October, showing negative results.
We appreciate the authors for describing their patients’ data in myasthenia with COVID-19 which would help clinicians caring for such patients.1 We have the following comments and queries. We would like to point out that, three out of the four patients who had SARS-CoV-2 infection were not having any infiltrates on chest x-ray, suggesting that these patients had mild COVID-19 infection.2 It is also noteworthy that all these patients who had a normal chest radiograph were either on very low dose azathioprine or no immunosuppressant apart from low dose steroids. As the authors rightly point out, the myasthenia disease activity prior to infection with SARS-CoV-2 is an important predictor of the severity of the myasthenic crisis. It is possible that patients with better control of symptoms or those on appropriate immunosuppression don’t develop a crisis with mild COVID-19. Secondly, it would be interesting to know what specific therapy for COVID-19 was offered to these patients. It is possible that steroids given as a part of therapy for COVID-19 could also act to stabilize disease activity in myasthenia. Similarly, IVIg given to manage Myasthenic crisis could have prevented progression in the severity of COVID-19. Likewise, myasthenic patients who receive drugs such as hydroxychloroquine and macrolides can have precipitation of myasthenic crisis.3,4 In case 2, we would also be interested to know if other causes of chest pain and breathlessness like pulmonary thromboembolism w...
We appreciate the authors for describing their patients’ data in myasthenia with COVID-19 which would help clinicians caring for such patients.1 We have the following comments and queries. We would like to point out that, three out of the four patients who had SARS-CoV-2 infection were not having any infiltrates on chest x-ray, suggesting that these patients had mild COVID-19 infection.2 It is also noteworthy that all these patients who had a normal chest radiograph were either on very low dose azathioprine or no immunosuppressant apart from low dose steroids. As the authors rightly point out, the myasthenia disease activity prior to infection with SARS-CoV-2 is an important predictor of the severity of the myasthenic crisis. It is possible that patients with better control of symptoms or those on appropriate immunosuppression don’t develop a crisis with mild COVID-19. Secondly, it would be interesting to know what specific therapy for COVID-19 was offered to these patients. It is possible that steroids given as a part of therapy for COVID-19 could also act to stabilize disease activity in myasthenia. Similarly, IVIg given to manage Myasthenic crisis could have prevented progression in the severity of COVID-19. Likewise, myasthenic patients who receive drugs such as hydroxychloroquine and macrolides can have precipitation of myasthenic crisis.3,4 In case 2, we would also be interested to know if other causes of chest pain and breathlessness like pulmonary thromboembolism were considered and ruled out as COVID-19 is known to be associated with a hypercoagulable state. In this series, none of the patients died, however, other series have reported a mortality of more than 30% in myasthenic crisis associated with COVID-19.5 It would also be interesting if the authors could present a comparative analysis of their patients who presented with myasthenic crisis with and without COVID-19 during this pandemic period to study the severity of crisis and response to therapy.
1. Hübers A, Lascano AM, Lalive PH. Management of patients with generalised myasthenia gravis and COVID-19: four case reports. J Neurol Neurosurg Psychiatry. 2020;91(10):1124-1125. doi:10.1136/jnnp-2020-323565
2. (Released by National Health Commission & National Administration of Traditional Chinese Medicine on March 3 2020). Diagnosis and Treatment Protocol for Novel Coronavirus Pneumonia (Trial Version 7). Chinese Medical Journal. 2020;133(9):1087–1095. doi:10.1097/CM9.0000000000000819
3. Elavarasi A, Goyal V. Hydroxychloroquine and myasthenia gravis-can one take this risk? Annals of Indian Academy of Neurology. 2020;23(3):360. doi:10.4103/aian.AIAN_363_20
4. Argov Z, Mastaglia FL. Disorders of Neuromuscular Transmission Caused by Drugs. N Engl J Med. 1979;301:409-413. doi:DOI: 10.1056/NEJM197908233010805
5. Camelo-Filho AE, Silva AMS, Estephan EP, et al. Myasthenia Gravis and COVID-19: Clinical Characteristics and Outcomes. Front Neurol. 2020;11. doi:10.3389/fneur.2020.01053
I read an interesting case report of GBS with antiganglioside antibodies in SARS-CoV-2 by Civardi et al1. We are also seeing various complications like GBS, pseudotumorcerebri, precipitation of stroke, seizures etc2 but do not have the access to antiganglioside antibodies but, all those who can afford and get it done we should try for that and get it documented for academic and research purpose in this pandemic of modern time of advanced technology. We may screen for ganglioside antibodies to assess autoimmunity in Covid-19 patients3. The gangliosides are particularly abundant in the brain and in the nervous system; they participate in maintenance and repair of neuronal cells, memory formation and synaptic transmission4. So we have to be watchful in this regard towards impairment of these neurological functions i.e. new autoimmune disorder like GBS, multiple sclerosis(MS), neuromyelitis optica spectrum disorders(NMO-SD), chronic inflammatory demyelinating neuropathy(CIDP) etc. and precipitation of neurodegenerative and cognitive disorders in acute, convalescent ant post recovery follow up. Of course the paediatric population is less affected but as the gangliodides also take part in the development and regeneration of neurons the SARS-CoV-2 may affect the growth and development of paediatric population.
As the intravenous immunoglobulins(IVIg) and plasmapharesis are useful in the treatment of GBS with antiganglioside antibodies the trial of IVIg, and monoclonal a...
I read an interesting case report of GBS with antiganglioside antibodies in SARS-CoV-2 by Civardi et al1. We are also seeing various complications like GBS, pseudotumorcerebri, precipitation of stroke, seizures etc2 but do not have the access to antiganglioside antibodies but, all those who can afford and get it done we should try for that and get it documented for academic and research purpose in this pandemic of modern time of advanced technology. We may screen for ganglioside antibodies to assess autoimmunity in Covid-19 patients3. The gangliosides are particularly abundant in the brain and in the nervous system; they participate in maintenance and repair of neuronal cells, memory formation and synaptic transmission4. So we have to be watchful in this regard towards impairment of these neurological functions i.e. new autoimmune disorder like GBS, multiple sclerosis(MS), neuromyelitis optica spectrum disorders(NMO-SD), chronic inflammatory demyelinating neuropathy(CIDP) etc. and precipitation of neurodegenerative and cognitive disorders in acute, convalescent ant post recovery follow up. Of course the paediatric population is less affected but as the gangliodides also take part in the development and regeneration of neurons the SARS-CoV-2 may affect the growth and development of paediatric population.
As the intravenous immunoglobulins(IVIg) and plasmapharesis are useful in the treatment of GBS with antiganglioside antibodies the trial of IVIg, and monoclonal antibodies in other neurological complications with SARS-CoV-2 along with monitoring of antiganglioside antibodies may prove to be a game changer, as it has been claimed to be effective in general treatment of COVID-195. Besides this there are emerging data that chloroquine which is under investigation for treating COVID-19, binds with high-affinity sialic acids and GM1 gangliosides and, in the presence of chloroquine, the SARS-CoV viral spike cannot bind gangliosides to infect the targeted cells. If it is confirmed to be beneficial and safety is established, chloroquine may have an additional therapeutic value in future patients with COVID-19–triggered GBS in conjunction with IVIg3.
References-
1. Civardi C, Collini A, Geda D J, Geda C. Antiganglioside antibodies in Guillain-Barré syndrome associated with SARS-CoV-2 infection. http://dx.doi.org/10.1136/jnnp-2020-324279
2. Shubhakaran K, Bhargava A, Sutaria N et al. Unpublished data.
3. Marinos C. Dalakas. Guillain-Barré syndrome: The first ocumented COVID-19–triggered autoimmune neurologic disease More to come with myositis in the offing. DOI:https://doi.org/10.1212/NXI.0000000000000781
4. Cutillo G, Saariaho A-H, Meri S. Physiology of gangliosides and the role of antiganglioside antibodies in human diseases. Cell Mol Immunol 2020;17:313–22.doi:10.1038/s41423-020-0388-9
5. Alan A. Nguyen, Saddiq B. Habiballah, Craig D. Platt, Raif S. Geha, Janet S. Chou, and Douglas R. McDonald. Immunoglobulins in the treatment of COVID-19 infection: Proceed with caution! Clin Immunol. 2020 Jul; 216: 108459. doi: 10.1016/j.clim.2020.108459
Russell et al. (1) published a retrospective cohort study with a population of former professional soccer players with known high neurodegenerative mortality. Findings showed that they are at lower risk of common mental health disorders and have lower rates of suicide than a matched general population. These findings are surprising and different from previous studies, which have used first-hand clinical accounts of ex-athletes who have lived with neurodegeneration (1). We suggest there may be reasons for this disparity and welcome critical dialogue with the authors of this research.
Cohort Comparison
Russell et al. has compared their soccer cohort with a matched population cohort. However, the matched cohort may also include those who have experienced repetitive head impacts, such as amateur soccer players, rugby players or boxers. Therefore, the study represents differences of elite versus non-elite rather than sport versus non-sport. While Russell recognises the healthy worker effect (2), it may have a greater influence in this study than presented.
Soccer Stoicism
Men’s engagement in health-seeking behaviours has been a long-standing concern in health care and is often attributed to factors such as stigma, hypermasculinity and stoicism (3). Furthermore, working-class sports such as soccer, require the acceptance of pain, suffering, and physical risk, so these players are more likely to ‘suffer in silence’ than the general population (4). Give...
Russell et al. (1) published a retrospective cohort study with a population of former professional soccer players with known high neurodegenerative mortality. Findings showed that they are at lower risk of common mental health disorders and have lower rates of suicide than a matched general population. These findings are surprising and different from previous studies, which have used first-hand clinical accounts of ex-athletes who have lived with neurodegeneration (1). We suggest there may be reasons for this disparity and welcome critical dialogue with the authors of this research.
Cohort Comparison
Russell et al. has compared their soccer cohort with a matched population cohort. However, the matched cohort may also include those who have experienced repetitive head impacts, such as amateur soccer players, rugby players or boxers. Therefore, the study represents differences of elite versus non-elite rather than sport versus non-sport. While Russell recognises the healthy worker effect (2), it may have a greater influence in this study than presented.
Soccer Stoicism
Men’s engagement in health-seeking behaviours has been a long-standing concern in health care and is often attributed to factors such as stigma, hypermasculinity and stoicism (3). Furthermore, working-class sports such as soccer, require the acceptance of pain, suffering, and physical risk, so these players are more likely to ‘suffer in silence’ than the general population (4). Given the effectiveness of masculine socialisation through sport participation, the absence of elevated medical reporting between male athletes and non-athletes does not indicate an actual absence of a larger disease profile. The lack of ex-elite athletes engaging with mental health support at a hospital may rather be indicative of health-avoidance behaviours.
Mental Health Concerns Defined by Hospital Admission
Using hospital admission records as the primary definition for mental health concerns is problematic. Hospital admission is reserved for the most severe acute psychiatric concerns. Therefore, such records miss many mental health concerns that are better managed in primary and community care settings. This may be particularly pertinent for this study, given that many of the sample have diagnosed dementia, and may be fully supported with their neuro-psychiatric needs by health care professionals outside the hospital context.
The Bigger Picture
It appears that only a selective subsection of data, or part of the picture, has been reported. No information on the length of visit to hospital, extent and nature of medical interventions, public health burden, number or frequency of visits by an individual and any further care has been provided. This information may illuminate other explanations for why there is a difference in common mental health disorders for soccer and match control samples.
Concluding thoughts
Russell et al assert research, “… has placed greater emphasis on psychiatric symptomatology in CTE. Nevertheless, data supporting this association are weak”. This study does little to support or contest this position. While the results presented are novel, they are not necessarily a significant contribution to the debate on the relationship between soccer participation, common mental health disorders and other neurological
References
(1) Russell, E. R., McCabe, T., Mackay, D. F., Stewart, K., MacLean, J. A., Pell, J. P., & Stewart, W. (2020). Mental health and suicide in former professional soccer players. Journal of Neurology, Neurosurgery and Psychiatry.
(2) Li CY, Sung FC. A review of the healthy worker effect in occupational epidemiology. Occup Med 1999;49:225–9.
(3) Wang Y, Hunt K, Nazareth I, Freemantle N, Petersen I. Do men consult less than women? An analysis of routinely collected UK general practice data. BMJ Open. 2013;3(8):e003320
(4) Anderson, E., & White, A. (2017). Sport, theory and social problems: A critical introduction. Routledge.
We thank White and colleagues for their correspondence on our article(1) and note many of the observations raised are already addressed by our robust study design and discussed in the original manuscript text. Importantly, we are quite clear throughout that this is a study designed to investigate whether there is higher risk of common mental health disorder in former professional soccer players than anticipated from general population controls.
Undoubtedly, there will be physically active individuals in our general population control group, including a number who might have participated in some form of contact sport. However, we would suggest this does not define our over 23,000 matched general population controls as a cohort of ‘non-elite’ athletes, as proposed by White et al. Instead, we would assert this merely underlines their legitimacy as a general population control cohort for comparison with our cohort of almost 8000 former professional soccer players.
Potential study limitations regarding healthy worker effect, illness behavior in former professional soccer players and use of hospitalization datasets are addressed in detail in our manuscript text. Regarding data on duration of hospital stay and therapy, while these might indeed be of interest in follow-on studies regarding illness severity, we would suggest that they are not immediately relevant to a study designed to address risk of common mental health disorder.
We thank White and colleagues for their correspondence on our article(1) and note many of the observations raised are already addressed by our robust study design and discussed in the original manuscript text. Importantly, we are quite clear throughout that this is a study designed to investigate whether there is higher risk of common mental health disorder in former professional soccer players than anticipated from general population controls.
Undoubtedly, there will be physically active individuals in our general population control group, including a number who might have participated in some form of contact sport. However, we would suggest this does not define our over 23,000 matched general population controls as a cohort of ‘non-elite’ athletes, as proposed by White et al. Instead, we would assert this merely underlines their legitimacy as a general population control cohort for comparison with our cohort of almost 8000 former professional soccer players.
Potential study limitations regarding healthy worker effect, illness behavior in former professional soccer players and use of hospitalization datasets are addressed in detail in our manuscript text. Regarding data on duration of hospital stay and therapy, while these might indeed be of interest in follow-on studies regarding illness severity, we would suggest that they are not immediately relevant to a study designed to address risk of common mental health disorder.
As White et al observe, while our data reporting lower risk of hospitalization for common mental health disorder in former professional soccer players might appear ‘surprising’, this is perhaps a reflection of methodological limitations and biases in previous reporting in this issue, as discussed in our text. As such, as a robust study specifically designed to address many previous limitations and minimize biases, we would disagree with White et al’s suggestion that our ‘surprising’ observations are ‘not necessarily a significant contribution’ to this field.
1 Russell ER, McCabe T, Mackay DF, et al Mental health and suicide in former professional soccer players Journal of Neurology, Neurosurgery & Psychiatry Published Online First: 21 July 2020. doi: 10.1136/jnnp-2020-323315
The recently published paper ‘Abnormal pain perception is associated with thalamo-cortico-striatal atrophy in C9orf72 expansion carriers in the GENFI cohort’ by Convery et al.[1] draws attention to a topic of great importance in the field of frontotemporal dementia (FTD) research. In this study, Convery and colleagues investigated differences in pain responsiveness within a group of patients with genetic FTD. Changes in pain responsiveness compared to baseline were captured using a scale designed by the group, and patients were scored from 0-3 (0 = no change, 0.5 = questionable or very mild change, 1 = mild change, 2 = moderate change, 3 = severe change). Within the sample, symptomatic C9orf72 mutation carriers (9/31) experienced greater changes in pain responsiveness than symptomatic MAPT (1/10) and GRN (1/24) mutation-carriers or normal controls (1/181). Within the C9orf72 mutation carriers, these changes were associated with thalamo-cortico-striatal atrophy.
This research brings attention to an important but little-investigated clinical feature of FTD. Changes in pain responsiveness, including both increases and decreases, have now been reported in both sporadic and genetic FTD, along with other somatic complaints.[1–4] However, the changes are not widely captured in either clinical or research settings, and the field lacks standardized and objective measurements to do so. The ability to measure changes in pain responsiveness may be a useful clinical marker to di...
The recently published paper ‘Abnormal pain perception is associated with thalamo-cortico-striatal atrophy in C9orf72 expansion carriers in the GENFI cohort’ by Convery et al.[1] draws attention to a topic of great importance in the field of frontotemporal dementia (FTD) research. In this study, Convery and colleagues investigated differences in pain responsiveness within a group of patients with genetic FTD. Changes in pain responsiveness compared to baseline were captured using a scale designed by the group, and patients were scored from 0-3 (0 = no change, 0.5 = questionable or very mild change, 1 = mild change, 2 = moderate change, 3 = severe change). Within the sample, symptomatic C9orf72 mutation carriers (9/31) experienced greater changes in pain responsiveness than symptomatic MAPT (1/10) and GRN (1/24) mutation-carriers or normal controls (1/181). Within the C9orf72 mutation carriers, these changes were associated with thalamo-cortico-striatal atrophy.
This research brings attention to an important but little-investigated clinical feature of FTD. Changes in pain responsiveness, including both increases and decreases, have now been reported in both sporadic and genetic FTD, along with other somatic complaints.[1–4] However, the changes are not widely captured in either clinical or research settings, and the field lacks standardized and objective measurements to do so. The ability to measure changes in pain responsiveness may be a useful clinical marker to differentiate FTD from other neurodegenerative diseases,[4] and, if the C9orf72 results of Convery et al. are replicated, as an indicator of possible genetic underpinnings.
Recent findings raise the possibility that changes in pain responsiveness differ between FTD phenotypes. Increased pain responsiveness has been reported in patients with semantic-variant primary progressive aphasia (svPPA), particularly in those with right-temporal atrophy, which stands in contrast to decreased pain responsiveness observed in behavioral-variant FTD (bvFTD).[2–5] These findings, in conjunction with those of Convery et al., highlight the importance of capturing directionality of change as well as severity. Similarly, analyses of different phenotypes within the FTD spectrum will be critical to broaden the clinical relevance of this research to sporadic FTD, as some phenotypes are rarely genetic (e.g., svPPA). In the Convery et al. paper, the overwhelming majority of symptomatic participants had bvFTD, which is typical for genetic cohorts. However, the extension of this research into sporadic cases raises the exciting question of whether changes in responsiveness to pain can distinguish between FTD phenotypes, which implicate overlapping but distinct neuroanatomical circuits. This question has great theoretical, as well as clinical, importance.
The Convery et al. paper highlights that altered responsiveness to pain was present in symptomatic but not presymptomatic genetic mutation carriers. It thus remains unclear whether altered pain responsiveness is an early feature of the disease or develops later. Elucidating this timeline will clarify the clinical utility of this research: whether it is useful for early diagnosis or for distinguishing between phenotypes after the dementia syndrome has developed.
As we continue to expand this line of research, it will be essential to develop both subjective and objective measurements of pain responsiveness and other somatic changes in patients with FTD. Refining our understanding of these changes has the potential to be useful in clinical and research settings alike.
1 Convery RS, Bocchetta M, Greaves CV, et al. Abnormal pain perception is associated with thalamo-cortico-striatal atrophy in C9orf72 expansion carriers in the GENFI cohort. J Neurol Neurosurg Psychiatry Published Online First: 5 August 2020. doi:10.1136/jnnp-2020-323279
2 Barker MS, Silverman HE, Fremont R, et al. ‘Everything hurts!’ Distress in semantic variant primary progressive aphasia. Cortex J Devoted Study Nerv Syst Behav 2020;127:396–8. doi:10.1016/j.cortex.2020.03.002
3 Snowden JS, Bathgate D, Varma A, et al. Distinct behavioural profiles in frontotemporal dementia and semantic dementia. J Neurol Neurosurg Psychiatry 2001;70:323–32. doi:10.1136/jnnp.70.3.323
4 Fletcher PD, Downey LE, Golden HL, et al. Pain and temperature processing in dementia: a clinical and neuroanatomical analysis. Brain J Neurol 2015;138:3360–72. doi:10.1093/brain/awv276
5 Ulugut Erkoyun H, Groot C, Heilbron R, et al. A clinical-radiological framework of the right temporal variant of frontotemporal dementia. Brain J Neurol 2020;143:2831–43. doi:10.1093/brain/awaa225
Jacobs et al. investigated the association of environmental factors and prodromal features with incident Parkinson's disease (PD) with special reference to the interaction of genetic factors [1]. The authors constructed polygenic risk scores (PRSs) for the risk assessment. Family history of PD, family history of dementia, non-smoking, low alcohol consumption, depression, daytime somnolence, epilepsy and earlier menarche were selected as PD risk factors. The adjusted odds ratio (OR) (95% confidence interval [CI]) of the highest 10% of PRSs for the risk of PD was 3.37 (2.41 to 4.70). I have some concerns about their study.
Regarding risk/protective factors of PD, Daniele et al. conducted a case-control study to performed a simultaneous evaluation of potential factors of PD [2]. Among 31 environmental and lifestyle factors, 9 factors were extracted by multivariate analysis. The adjusted OR (95% CI) of coffee consumption, smoking, physical activity, family history of PD, dyspepsia, exposure to pesticides, metals, and general anesthesia were 0.6 (0.4-0.9), 0.7 (0.6-0.9), 0.8 (0.7-0.9), 3.2 (2.2- 4.8), 1.8 (1.3-2.4), 2.3 (1.3- 4.2), 5.6 (2.3-13.7), 2.8 (1.5-5.4), and 6.1 (2.9-12.7), respectively. Family history of PD and non-smoking were common risk factors, which had also been reported by several prospective studies.
Regarding smoking, Angelopoulou et al. investigated the association between environmental factors and PD subtypes (early-onset, mid-and-late on...
Jacobs et al. investigated the association of environmental factors and prodromal features with incident Parkinson's disease (PD) with special reference to the interaction of genetic factors [1]. The authors constructed polygenic risk scores (PRSs) for the risk assessment. Family history of PD, family history of dementia, non-smoking, low alcohol consumption, depression, daytime somnolence, epilepsy and earlier menarche were selected as PD risk factors. The adjusted odds ratio (OR) (95% confidence interval [CI]) of the highest 10% of PRSs for the risk of PD was 3.37 (2.41 to 4.70). I have some concerns about their study.
Regarding risk/protective factors of PD, Daniele et al. conducted a case-control study to performed a simultaneous evaluation of potential factors of PD [2]. Among 31 environmental and lifestyle factors, 9 factors were extracted by multivariate analysis. The adjusted OR (95% CI) of coffee consumption, smoking, physical activity, family history of PD, dyspepsia, exposure to pesticides, metals, and general anesthesia were 0.6 (0.4-0.9), 0.7 (0.6-0.9), 0.8 (0.7-0.9), 3.2 (2.2- 4.8), 1.8 (1.3-2.4), 2.3 (1.3- 4.2), 5.6 (2.3-13.7), 2.8 (1.5-5.4), and 6.1 (2.9-12.7), respectively. Family history of PD and non-smoking were common risk factors, which had also been reported by several prospective studies.
Regarding smoking, Angelopoulou et al. investigated the association between environmental factors and PD subtypes (early-onset, mid-and-late onset, familial and sporadic) [3]. The adjusted OR (95% CI) of smoking for PD overall, mid-and-late onset PD, familial PD, and sporadic PD were 0.48 (0.35-0.67), 0.46 (0.32-0.66), 0.53 (0.34-0.83) and 0.46 (0.32-0.65), respectively. In addition, there was an inverse linear association of PD with pack-years of smoking, except for early-onset PD. Additionally, the adjusted OR (95% CI) of coffee consumption for PD overall, early-onset PD, and familial PD were 0.52 (0.29-0.91), 0.16 (0.05-0.53) and 0.36 (0.17-0.75), respectively. Although the mechanism of the association might be difficult to be confirmed, smokers have a trend of high prevalence of coffee consumption.
Finally, Li et al. evaluated whether the genetic profile might modify PD development and cerebrospinal fluid (CSF) pathological biomarkers by using single nucleotide polymorphisms (SNPs) and PRSs [4]. Some SNPs had significant correlations with PD, and PRSs could predict PD risk and the age at onset. In contrast, the CSF α-synuclein level had no significant correlation with the PRSs in normal subjects. Anyway, further studies are needed to verify PD determinants and gene-environment interactions.
References
1. Jacobs BM, Belete D, Bestwick J, et al. Parkinson's disease determinants, prediction and gene-environment interactions in the UK Biobank. J Neurol Neurosurg Psychiatry. 2020 Oct;91(10):1046-1054.
2. Daniele B, Roberta P, Andrea F, et al. Risk factors of Parkinson's disease: Simultaneous assessment, interactions and etiological subtypes. Neurology. 2020 Sep 17 doi: 10.1212/WNL.0000000000010813
3. Angelopoulou E, Bozi M, Simitsi AM, et al. The relationship between environmental factors and different Parkinson's disease subtypes in Greece: Data analysis of the Hellenic Biobank of Parkinson's disease. Parkinsonism Relat Disord. 2019 Oct;67:105-112.
4. Li WW, Fan DY, Shen YY, et al. Association of the polygenic risk score with the incidence risk of Parkinson's disease and cerebrospinal fluid α-Synuclein in a Chinese cohort. Neurotox Res. 2019 Oct;36(3):515-522.
Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become one of the most severe pandemic the world has ever seen. Based on data from Johns Hopkins University, around 26.3 million cases have been detected and around 0.9 million patients have died of COVID-19 globally as of September 04, 2020. The neurological sequelae of COVID-19 include a para/post-infectious, immune or antibody-mediated phenomenon, which classically manifests as Guillain-Barré syndrome (GBS).[1, 2]
We read the systematic review by Uncini et al with great interest. In an instant systematic review, the authors reported 42 patients of GBS associated with COVID-19 from 33 retrieved articles. All of these articles had been reported from 13 developed countries.[3] The authors mentioned regarding the chronology of publication of case reports/series starting from China followed by Iran, France, Italy, Spain and USA which seemed to be related to the track of SARS-CoV-2 infection spread. However, the authors did not discuss why such cases/series had remained under-reported from developing countries. A comprehensive, advanced search of PubMed using the terms ‘SARS-CoV-2’ OR ‘COVID-19’ AND ‘Guillain-Barré syndrome’ on September 04, 2020, led to retrieval of two additional articles from developing countries, one each from Brazil and Morocco.[4 ,5] As of September 04, 2020, Brazil and India had the 2nd and 3rd highest number of COVI...
Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become one of the most severe pandemic the world has ever seen. Based on data from Johns Hopkins University, around 26.3 million cases have been detected and around 0.9 million patients have died of COVID-19 globally as of September 04, 2020. The neurological sequelae of COVID-19 include a para/post-infectious, immune or antibody-mediated phenomenon, which classically manifests as Guillain-Barré syndrome (GBS).[1, 2]
We read the systematic review by Uncini et al with great interest. In an instant systematic review, the authors reported 42 patients of GBS associated with COVID-19 from 33 retrieved articles. All of these articles had been reported from 13 developed countries.[3] The authors mentioned regarding the chronology of publication of case reports/series starting from China followed by Iran, France, Italy, Spain and USA which seemed to be related to the track of SARS-CoV-2 infection spread. However, the authors did not discuss why such cases/series had remained under-reported from developing countries. A comprehensive, advanced search of PubMed using the terms ‘SARS-CoV-2’ OR ‘COVID-19’ AND ‘Guillain-Barré syndrome’ on September 04, 2020, led to retrieval of two additional articles from developing countries, one each from Brazil and Morocco.[4 ,5] As of September 04, 2020, Brazil and India had the 2nd and 3rd highest number of COVID-19 cases (Johns Hopkins data), yet only one case of COVID-19-associated GBS had been reported from Brazil and no case had been reported from India. An Italian study reported a 5.4-fold increase in the incidence of GBS during this pandemic.[2] In contrast, the number of GBS cases in Bangladesh, a developing country, had decreased during the pandemic (personal communication with country coordinator (Bangladesh) of International GBS Outcome Study (IGOS), August 2020), even though Bangladesh reported the highest number of GBS cases worldwide in the IGOS.
The lack of or inadequate testing facilities and structural barriers to getting tested for COVID-19, i.e., excessive waiting time or lack of one-stop services may contribute to under-reporting of COVID-19-associated GBS in developing countries. We assume that some patients with GBS in developing countries did not seek hospital care due to the lock-down, lack of public transport services, social stigma and fear of nosocomial infection. However, it requires further exploration if truly there were no COVID-19-associated GBS cases in developing countries or these cases had remained under-reported.
Patients of GBS associated with COVID-19 may not present with typical symptoms. For instance, the first reported case of GBS associated with SARS-CoV-2 infection was para-infectious, rather than the classical post-infectious presentation.[1] Some cases of GBS may also be negative for SARS-CoV-2 in reverse transcriptase polymerase chain reaction (RT-PCR) tests, as reported by an Italian study.[2] Moreover, if a patient develops GBS long after the acute infection subsides, RT-PCR testing for SARS-CoV-2 may also be negative. Analysis of serum IgG and IgM for SARS-CoV-2 may help to confirm or exclude antecedent SARS-CoV-2 infection, though such tests may not be available in developing countries—which may also result in underreporting of COVID-19-associated GBS.
The high number of reported cases of COVID-19-associated GBS worldwide provides evidence of a possible association between GBS and COVID-19. Therefore, during this pandemic, clinicians and neurologists should be aware that patients presenting with GBS, even in the absence of cough, fever, respiratory distress or any systemic symptoms, may represent the first manifestation of COVID-19. During this global pandemic, the differential diagnosis of COVID-19-associated GBS should be considered for all cases of GBS, until and unless confirmed otherwise. We call for attention of the clinicians, especially neurologists in developing countries to strengthen surveillance system for identification, reporting and better management of COVID-19-associated GBS.
References
1. Zhao H, Shen D, Zhou H, et al. Guillain-Barré syndrome associated with SARS-CoV-2 infection: causality or coincidence? Lancet Neurol 2020;19(5):383-84. doi: 10.1016/s1474-4422(20)30109-5
2. Gigli GL, Bax F, Marini A, et al. Guillain-Barré syndrome in the COVID-19 era: just an occasional cluster? J Neurol 2020:1-3. doi: 10.1007/s00415-020-09911-3
3. Uncini A, Vallat J-M, Jacobs BC. Guillain-Barré syndrome in SARS-CoV-2 infection: an instant systematic review of the first six months of pandemic. Journal of Neurology, Neurosurgery & Psychiatry 2020:jnnp-2020-324491. doi: 10.1136/jnnp-2020-324491
4. El Otmani H, El Moutawakil B, Rafai MA, et al. Covid-19 and Guillain-Barré syndrome: More than a coincidence! Revue neurologique 2020;176(6):518-19. doi: 10.1016/j.neurol.2020.04.007
5. Frank CHM, Almeida TVR, Marques EA, et al. Guillain-Barré Syndrome Associated with SARS-CoV-2 Infection in a Pediatric Patient. J Trop Pediatr 2020 doi: 10.1093/tropej/fmaa044
We read with great interest the article by Macerollo et al. entitled “Non-invasive intervention for motor signs of Parkinson’s Disease: the effect of vibratory stimuli.”[1] The authors evaluated the use of a wearable device called the "Emma Watch" that produces a constant vibratory stimulus (200 Hz) to the wrist with frequencies of 20 bpm or 60 bpm in terms of motor function of the arms of 16 patients with Parkinson’s disease (PD).[1] Motor performance was assessed through three different tasks: a nine-peg hole test, a STYAR tracing task, and a SPIRAL tracking test.[1] The authors found that patients with PD who used the device with 200 Hz peripheral vibration modulated by 60 bpm as they carried out these tasks performed better in terms of speed and precision.[1] The final conclusion was that vibrotactile stimulation can improve motor function in patients with PD.[1] It is important to comment that the authors did not discuss their results in terms of other studies in the literature, including one systematic review published in 2014 [2] and another with a meta-analysis published in 2020. [3] In these studies, vibratory stimulation in patients with PD was generally seen to yield positive results with regard to balance and gait. [2,3] From a historical point of view, the pioneering and seminal work of Jean-Martin Charcot, who used a vibrating chair to treat patients with PD, should also be noted.[4,5]
1. Macerollo A, Holz C, Cletheror D, et al. Non-invasiv...
Show MoreIn clinical practice, neuropathies are groups of disorders with curable, treatable, and non-treatable aetiologies, the later accounting for most of the cases.[1] Every newly identified disorder either on the basis of etiology or syndromic group responding to particular treatment brings hope for few more patients.
Show MoreThis study by Shin J Oh et al [2] brings hope for some patients who were previously either classified as axonal neuropathy of undetermined cause orin the evolutionary phase of a neurodegenerative diseases (such as anterior horn cell diseases). Thus, in the absence of any evidence, such patients usually remained deprived of any immunotherapies and succumbed to the progressive disease. Now with this piece of information, it can be inferred that all those patients presenting with chronic (more than 2 months), symmetrical or asymmetrical, proximal and distal weakness without any evidence of demyelination (i.e. axonal) on nerve conduction studies and without any known secondary causes of axonal polyneuropathy could qualify for immunotherapy when nerve biopsy or CSF protein > 55 mg/dl shows evidence of inflammation. Thus, chronic inflammatory polyneuropathy syndrome would be a more apt diagnosis with two variants: demyelinating (usual Chronic inflammatory demyelinating polyneuropathy, CIDP) and axonal, much like Guillain-Barre syndrome.
However, it can be noted that all the patients included in the study did not qualify for CIAP. There were six patients w...
We would like to thank the author for pointing out the fact that a proper disease control in myasthenia gravis (MG) probably predicts a favourable outcome during SARS-CoV-2 infection.
MG exacerbation was only observed in one patient (case 1) treated successfully with immunoglobulins (IVIG) as described. No MG crisis was reported during this period in non-infected patients.
None of the four patients described in our case report received COVID-19 related treatment, namely antiviral and/or hydroxychloroquine. Case 4 received antibiotherapy for 5 days (azythromicine and tazobactam).
Regarding case 2, this patient presents with recurring symptoms of fever and shortness of breath since March 2020. In this regard a chest CT and repeated D-dimers were performed in October, showing negative results.
We appreciate the authors for describing their patients’ data in myasthenia with COVID-19 which would help clinicians caring for such patients.1 We have the following comments and queries. We would like to point out that, three out of the four patients who had SARS-CoV-2 infection were not having any infiltrates on chest x-ray, suggesting that these patients had mild COVID-19 infection.2 It is also noteworthy that all these patients who had a normal chest radiograph were either on very low dose azathioprine or no immunosuppressant apart from low dose steroids. As the authors rightly point out, the myasthenia disease activity prior to infection with SARS-CoV-2 is an important predictor of the severity of the myasthenic crisis. It is possible that patients with better control of symptoms or those on appropriate immunosuppression don’t develop a crisis with mild COVID-19. Secondly, it would be interesting to know what specific therapy for COVID-19 was offered to these patients. It is possible that steroids given as a part of therapy for COVID-19 could also act to stabilize disease activity in myasthenia. Similarly, IVIg given to manage Myasthenic crisis could have prevented progression in the severity of COVID-19. Likewise, myasthenic patients who receive drugs such as hydroxychloroquine and macrolides can have precipitation of myasthenic crisis.3,4 In case 2, we would also be interested to know if other causes of chest pain and breathlessness like pulmonary thromboembolism w...
Show MoreI read an interesting case report of GBS with antiganglioside antibodies in SARS-CoV-2 by Civardi et al1. We are also seeing various complications like GBS, pseudotumorcerebri, precipitation of stroke, seizures etc2 but do not have the access to antiganglioside antibodies but, all those who can afford and get it done we should try for that and get it documented for academic and research purpose in this pandemic of modern time of advanced technology. We may screen for ganglioside antibodies to assess autoimmunity in Covid-19 patients3. The gangliosides are particularly abundant in the brain and in the nervous system; they participate in maintenance and repair of neuronal cells, memory formation and synaptic transmission4. So we have to be watchful in this regard towards impairment of these neurological functions i.e. new autoimmune disorder like GBS, multiple sclerosis(MS), neuromyelitis optica spectrum disorders(NMO-SD), chronic inflammatory demyelinating neuropathy(CIDP) etc. and precipitation of neurodegenerative and cognitive disorders in acute, convalescent ant post recovery follow up. Of course the paediatric population is less affected but as the gangliodides also take part in the development and regeneration of neurons the SARS-CoV-2 may affect the growth and development of paediatric population.
Show MoreAs the intravenous immunoglobulins(IVIg) and plasmapharesis are useful in the treatment of GBS with antiganglioside antibodies the trial of IVIg, and monoclonal a...
Russell et al. (1) published a retrospective cohort study with a population of former professional soccer players with known high neurodegenerative mortality. Findings showed that they are at lower risk of common mental health disorders and have lower rates of suicide than a matched general population. These findings are surprising and different from previous studies, which have used first-hand clinical accounts of ex-athletes who have lived with neurodegeneration (1). We suggest there may be reasons for this disparity and welcome critical dialogue with the authors of this research.
Cohort Comparison
Russell et al. has compared their soccer cohort with a matched population cohort. However, the matched cohort may also include those who have experienced repetitive head impacts, such as amateur soccer players, rugby players or boxers. Therefore, the study represents differences of elite versus non-elite rather than sport versus non-sport. While Russell recognises the healthy worker effect (2), it may have a greater influence in this study than presented.
Soccer Stoicism
Show MoreMen’s engagement in health-seeking behaviours has been a long-standing concern in health care and is often attributed to factors such as stigma, hypermasculinity and stoicism (3). Furthermore, working-class sports such as soccer, require the acceptance of pain, suffering, and physical risk, so these players are more likely to ‘suffer in silence’ than the general population (4). Give...
We thank White and colleagues for their correspondence on our article(1) and note many of the observations raised are already addressed by our robust study design and discussed in the original manuscript text. Importantly, we are quite clear throughout that this is a study designed to investigate whether there is higher risk of common mental health disorder in former professional soccer players than anticipated from general population controls.
Undoubtedly, there will be physically active individuals in our general population control group, including a number who might have participated in some form of contact sport. However, we would suggest this does not define our over 23,000 matched general population controls as a cohort of ‘non-elite’ athletes, as proposed by White et al. Instead, we would assert this merely underlines their legitimacy as a general population control cohort for comparison with our cohort of almost 8000 former professional soccer players.
Potential study limitations regarding healthy worker effect, illness behavior in former professional soccer players and use of hospitalization datasets are addressed in detail in our manuscript text. Regarding data on duration of hospital stay and therapy, while these might indeed be of interest in follow-on studies regarding illness severity, we would suggest that they are not immediately relevant to a study designed to address risk of common mental health disorder.
As White et al observe, wh...
Show MoreThe recently published paper ‘Abnormal pain perception is associated with thalamo-cortico-striatal atrophy in C9orf72 expansion carriers in the GENFI cohort’ by Convery et al.[1] draws attention to a topic of great importance in the field of frontotemporal dementia (FTD) research. In this study, Convery and colleagues investigated differences in pain responsiveness within a group of patients with genetic FTD. Changes in pain responsiveness compared to baseline were captured using a scale designed by the group, and patients were scored from 0-3 (0 = no change, 0.5 = questionable or very mild change, 1 = mild change, 2 = moderate change, 3 = severe change). Within the sample, symptomatic C9orf72 mutation carriers (9/31) experienced greater changes in pain responsiveness than symptomatic MAPT (1/10) and GRN (1/24) mutation-carriers or normal controls (1/181). Within the C9orf72 mutation carriers, these changes were associated with thalamo-cortico-striatal atrophy.
Show MoreThis research brings attention to an important but little-investigated clinical feature of FTD. Changes in pain responsiveness, including both increases and decreases, have now been reported in both sporadic and genetic FTD, along with other somatic complaints.[1–4] However, the changes are not widely captured in either clinical or research settings, and the field lacks standardized and objective measurements to do so. The ability to measure changes in pain responsiveness may be a useful clinical marker to di...
Jacobs et al. investigated the association of environmental factors and prodromal features with incident Parkinson's disease (PD) with special reference to the interaction of genetic factors [1]. The authors constructed polygenic risk scores (PRSs) for the risk assessment. Family history of PD, family history of dementia, non-smoking, low alcohol consumption, depression, daytime somnolence, epilepsy and earlier menarche were selected as PD risk factors. The adjusted odds ratio (OR) (95% confidence interval [CI]) of the highest 10% of PRSs for the risk of PD was 3.37 (2.41 to 4.70). I have some concerns about their study.
Regarding risk/protective factors of PD, Daniele et al. conducted a case-control study to performed a simultaneous evaluation of potential factors of PD [2]. Among 31 environmental and lifestyle factors, 9 factors were extracted by multivariate analysis. The adjusted OR (95% CI) of coffee consumption, smoking, physical activity, family history of PD, dyspepsia, exposure to pesticides, metals, and general anesthesia were 0.6 (0.4-0.9), 0.7 (0.6-0.9), 0.8 (0.7-0.9), 3.2 (2.2- 4.8), 1.8 (1.3-2.4), 2.3 (1.3- 4.2), 5.6 (2.3-13.7), 2.8 (1.5-5.4), and 6.1 (2.9-12.7), respectively. Family history of PD and non-smoking were common risk factors, which had also been reported by several prospective studies.
Regarding smoking, Angelopoulou et al. investigated the association between environmental factors and PD subtypes (early-onset, mid-and-late on...
Show MoreDear sir,
Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become one of the most severe pandemic the world has ever seen. Based on data from Johns Hopkins University, around 26.3 million cases have been detected and around 0.9 million patients have died of COVID-19 globally as of September 04, 2020. The neurological sequelae of COVID-19 include a para/post-infectious, immune or antibody-mediated phenomenon, which classically manifests as Guillain-Barré syndrome (GBS).[1, 2]
We read the systematic review by Uncini et al with great interest. In an instant systematic review, the authors reported 42 patients of GBS associated with COVID-19 from 33 retrieved articles. All of these articles had been reported from 13 developed countries.[3] The authors mentioned regarding the chronology of publication of case reports/series starting from China followed by Iran, France, Italy, Spain and USA which seemed to be related to the track of SARS-CoV-2 infection spread. However, the authors did not discuss why such cases/series had remained under-reported from developing countries. A comprehensive, advanced search of PubMed using the terms ‘SARS-CoV-2’ OR ‘COVID-19’ AND ‘Guillain-Barré syndrome’ on September 04, 2020, led to retrieval of two additional articles from developing countries, one each from Brazil and Morocco.[4 ,5] As of September 04, 2020, Brazil and India had the 2nd and 3rd highest number of COVI...
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