We thank Kokubun et al. [1], for their interest in our study. First,
as we stated in our paper [2], our new proposed criteria provided, with a
single study, globally, similar proportions and diagnostic shifts, to
those found with older criteria and serial studies [3, 4]. There could be
no indication from our study that in each and every single individual
patient, similar diagnoses would be reached.
Uncini et al. have however very recently, in a editorial on our paper
in this journal, reported the results of the application of our criteria
to their cohort of 55 patients [5]. This provided an albeit retrospective,
validation of our criteria in another European population. They precisely
used as gold-standard the serial studies available to them. For acute
inflammatory demyelinating polyradiculoneuropathy (AIDP), they found that
our criteria had a 70% sensitivity and 96% specificity with one study,
versus 94% and 72% respectively obtained with Hadden et al.'s criteria
[6]. For axonal GBS, our criteria had a sensitivity of 81% and a
specificity of 94% with one study, versus 47% and 100% respectively with
Hadden et al.'s criteria. Hence, diagnostic accuracy was equivalent with
our criteria to that of Hadden et al.'s criteria for AIDP (83.6% for both)
and substantially higher with our criteria for axonal GBS (89.1% vs. 80%),
considering a single electrophysiological evaluation.
Patient 1 presented by Kokubun et al. illustrates the superior
accuracy of our criteria which allowed early identification of axonal GBS,
with a single study, in keeping with the serological data provided.
Kokubun et al.'s Patient 2, for her part, illustrates the fact that
delayed appearance of electrophysiological abnormalities may, in a
proportion of cases, result in late diagnostic confirmation of GBS
subtype, irrespective of criteria utilized.
As we also mentioned in our paper, our analysis otherwise
demonstrated a sensitivity of 91.3% for a definite, i.e. unequivocal,
diagnosis of GBS, irrespective of subtype. This level of sensitivity is,
for a diagnostic test in the acute setting of this disease, and in
comparison to other neuropathies such as chronic inflammatory
demyelinating polyneuropathy [7], very high, and unambiguously shows, the
practical usefulness of electrophysiology with our criteria with a single
test.
We are grateful to Kokubun et al. who state that our criteria may be
more appropriate than previous criteria [1]. We fully agree that in a
minority of cases, accurate diagnosis of GBS subtype may require a repeat
set of nerve conductions. However, how relevant this may be from a purely
clinical and diagnostic perspective, weeks after onset and treatment,
remains very debatable in our opinion, particularly given the high
accuracy of our criteria for GBS subtype, already achieved with a single
study.
References.
1.Kokubun N, Nagashima T, Odamura M, Hirata K, Yuki N. Timing is
crucial for electrodiagnosis of Guillain-Barré syndrome. J Neurol
Neurosurg Psychiatry 2014, EPub before print.
2. Rajabally YA, Durand MC, Mitchell J, et al. Electrophysiological
diagnosis of Guillain-Barré syndrome subtype: could a single study
suffice? J Neurol Neurosurg Psychiatry 2014 May 9 EPub ahead of print.
3. Uncini A, Manzoli C, Notturno F, Capasso M. Pitfalls in
electrodiagnosis of Guillain-
Barré syndrome subtypes. J Neurol Neurosurg Psychiatry 2010;81:1157-1163.
4. Shahrizaila N, Goh KJ, Abdullah S, Kuppusamy R, Yuki N. Two sets
of nerve conduction studies may suffice in reaching a reliable
electrodiagnosis in Guillain-Barré syndrome. Clin Neurophysiol
2013;124:1456-1459.
5. Uncini A, Zappasodi F, Notturno F. Electrodiagnosis of GBS
subtypes by a single study: not yet the squaring of the circle. J Neurol
Neurosurg Psychiatry 2014 June 5 EPub ahead of print.
6. Hadden RD, Cornblath DR, Hughes RA, et al. Electrophysiological
classification of Guillain-Barré syndrome: clinical associations and
outcome. Ann Neurol 1998;44:780-788.
7. Rajabally YA, Nicolas G, Piéret F, et al. Validity of diagnostic
criteria for chronic inflammatory demyelinating polyneuropathy: a
multicentre European study. J Neurol Neurosurg Psychiatry 2009;80:1364-
1368.
Conflict of Interest:
Y.A.R. has received speaker/consultancy honoraria from LfB France, Griffols, and BPL and has received educational sponsorships from LfB France, CSL Behring and Baxter.
G.N. has received deparmental research support/honoraria from Debiopharm, GSK, LfB France, Ipsen and Novartis.
We thank Kokubun et al. [1], for their interest in our study. First, as we stated in our paper [2], our new proposed criteria provided, with a single study, globally, similar proportions and diagnostic shifts, to those found with older criteria and serial studies [3, 4]. There could be no indication from our study that in each and every single individual patient, similar diagnoses would be reached.
Uncini et al. have however very recently, in a editorial on our paper in this journal, reported the results of the application of our criteria to their cohort of 55 patients [5]. This provided an albeit retrospective, validation of our criteria in another European population. They precisely used as gold-standard the serial studies available to them. For acute inflammatory demyelinating polyradiculoneuropathy (AIDP), they found that our criteria had a 70% sensitivity and 96% specificity with one study, versus 94% and 72% respectively obtained with Hadden et al.'s criteria [6]. For axonal GBS, our criteria had a sensitivity of 81% and a specificity of 94% with one study, versus 47% and 100% respectively with Hadden et al.'s criteria. Hence, diagnostic accuracy was equivalent with our criteria to that of Hadden et al.'s criteria for AIDP (83.6% for both) and substantially higher with our criteria for axonal GBS (89.1% vs. 80%), considering a single electrophysiological evaluation.
Patient 1 presented by Kokubun et al. illustrates the superior accuracy of our criteria which allowed early identification of axonal GBS, with a single study, in keeping with the serological data provided. Kokubun et al.'s Patient 2, for her part, illustrates the fact that delayed appearance of electrophysiological abnormalities may, in a proportion of cases, result in late diagnostic confirmation of GBS subtype, irrespective of criteria utilized.
As we also mentioned in our paper, our analysis otherwise demonstrated a sensitivity of 91.3% for a definite, i.e. unequivocal, diagnosis of GBS, irrespective of subtype. This level of sensitivity is, for a diagnostic test in the acute setting of this disease, and in comparison to other neuropathies such as chronic inflammatory demyelinating polyneuropathy [7], very high, and unambiguously shows, the practical usefulness of electrophysiology with our criteria with a single test.
We are grateful to Kokubun et al. who state that our criteria may be more appropriate than previous criteria [1]. We fully agree that in a minority of cases, accurate diagnosis of GBS subtype may require a repeat set of nerve conductions. However, how relevant this may be from a purely clinical and diagnostic perspective, weeks after onset and treatment, remains very debatable in our opinion, particularly given the high accuracy of our criteria for GBS subtype, already achieved with a single study.
References.
1.Kokubun N, Nagashima T, Odamura M, Hirata K, Yuki N. Timing is crucial for electrodiagnosis of Guillain-Barré syndrome. J Neurol Neurosurg Psychiatry 2014, EPub before print.
2. Rajabally YA, Durand MC, Mitchell J, et al. Electrophysiological diagnosis of Guillain-Barré syndrome subtype: could a single study suffice? J Neurol Neurosurg Psychiatry 2014 May 9 EPub ahead of print.
3. Uncini A, Manzoli C, Notturno F, Capasso M. Pitfalls in electrodiagnosis of Guillain- Barré syndrome subtypes. J Neurol Neurosurg Psychiatry 2010;81:1157-1163.
4. Shahrizaila N, Goh KJ, Abdullah S, Kuppusamy R, Yuki N. Two sets of nerve conduction studies may suffice in reaching a reliable electrodiagnosis in Guillain-Barré syndrome. Clin Neurophysiol 2013;124:1456-1459.
5. Uncini A, Zappasodi F, Notturno F. Electrodiagnosis of GBS subtypes by a single study: not yet the squaring of the circle. J Neurol Neurosurg Psychiatry 2014 June 5 EPub ahead of print.
6. Hadden RD, Cornblath DR, Hughes RA, et al. Electrophysiological classification of Guillain-Barré syndrome: clinical associations and outcome. Ann Neurol 1998;44:780-788.
7. Rajabally YA, Nicolas G, Piéret F, et al. Validity of diagnostic criteria for chronic inflammatory demyelinating polyneuropathy: a multicentre European study. J Neurol Neurosurg Psychiatry 2009;80:1364- 1368.
Conflict of Interest:
Y.A.R. has received speaker/consultancy honoraria from LfB France, Griffols, and BPL and has received educational sponsorships from LfB France, CSL Behring and Baxter. G.N. has received deparmental research support/honoraria from Debiopharm, GSK, LfB France, Ipsen and Novartis.