ReviewAdvances in primary writing tremor☆
Introduction
Tremor is an involuntary oscillation of a body part and is the most common form of movement disorder. Task-specific tremor is largely or solely limited to a specific task or movement, such as writing, speaking, smiling, or standing [1]. Primary writing tremor (PWT) is considered to be a type of task-specific tremor in which tremor occurs and interferes with handwriting [2], [3], [4], [5]. The pathophysiology of PWT is unknown [3], [6], [7]. There is still some controversy as to whether PWT is a variant of essential tremor [7], [8], a type of focal dystonia such as writer’s cramp [9], or a separate nosological entity [2], [6].
Section snippets
Clinical manifestation of PWT
First described in 1979 by Rothwell et al. [10], the term PWT is used to define a specific action tremor in which pronation of the forearm elicits a pronation/supination tremor during writing but not seen during other arm movements. They described a right-handed young man who presented with difficulty writing caused by bursts of tremor which occurred whenever the right forearm was pronated. Patients are classified as having either type A or type B PWT depending on whether tremor appears during
Hypothesis
The origin of the entity remains unknown, but that the following findings argue for or against PWT being an essential tremor variant, a type of dystonia, or a separate entity.
Treatment of PWT
No double-blind studies of the condition have been reported. Medical treatment includes the use of propranolol, primidone, and anticholinergic medications [4]. Treatment of PWT with for oral drugs may not be effective and functional neurosurgery has been advocated for medication-resistant patients [24]. Treatment of essential tremor with propranolol, primidone, diazepam, topiramate may only be successful in about 50% of cases [25] (Table 2).
Sixty percent of patients treated reported that they
Summary
Primary writing tremor is a condition in which tremor predominantly or only occurs during writing. Patients are classified as having either type A or type B PWT depending on whether tremor appears during writing (type A: task induced tremor) or while writing or also when adopting the hand position normally used for writing (type B: positionally sensitive tremor). The pathophysiology of PWT is different from that of writer’s cramp and partially also from that of essential tremor. PWT may be a
References (30)
Origins of tremor
Lancet
(2000)- et al.
Primary writing tremor: motor cortex reorganization and disinhibition
J Clin Neurosci
(2005) - et al.
Primary writing tremor
Brain
(1995) - et al.
Deep brain stimulation for trauma: patient selection and evaluation
Mov Disord
(2002) - et al.
Thalamic stimulation for primary writing tremor
J Neurol
(2001) - et al.
Changes in cortical inhibition during task-specific contractions in primary writing tremor patients
Mov Disord
(2006) - et al.
Neurophysiological investigations in patients with primary writing tremor
Mov Disord
(2002) - et al.
Bilateral primary writing tremor
Eur J Neurol
(1998) - et al.
Focal task-specific tremors
Mov Disord
(1996) - et al.
Primary writing tremor
J Neurol Neurosurg Psychiatr
(1979)
Primary writing tremor: report of a case successfully treated with botulinum toxin A injections and discussion of underlying mechanism
Mov Disord
Impairment of cortical inhibition in focal dystonia
Ann Neurol
Changes in the balance between motor cortical excitation and inhibition in focal, task specific dystonia
J Neurol Neurosurg Psychiatr
Abnormal cortical motor excitability in dystonia
Neurology
The corticomotor representation of upper limb muscles in writer’s cramp and changes following botulinum toxin injection
Brain
Cited by (30)
Principles and Practice of Movement Disorders
2021, Principles and Practice of Movement DisordersWriting tremor: Should we look for a TOR1A mutation?
2017, Journal of the Neurological SciencesMild cerebello-thalamo-cortical impairment in patients with normal dopaminergic scans (SWEDD)
2016, Parkinsonism and Related DisordersCitation Excerpt :In particular, we can speculate that the CTC alteration may be part of a network disorder, that involves, besides the CTC circuit, the sensorimotor system [1] and the brainstem [21]. We also observed that the abnormalities in the CTC connectivity may be differently evident depending on the state of motor activity (at rest but not during arm extension), as well as it has been recently demonstrated by functional MRI in other tremulous disorders, including essential tremor and primary writing tremor [27,28]. In conclusion, we suggest that such a disrupted CTC circuit may have a pathogenic role in motor disturbances of tremulous patients with SWEDD.
Writer's cramp
2015, ToxiconCitation Excerpt :Primary writing tremor (PWT) is a task-specific tremor in which tremor occurs only with writing. PWT may be difficult to distinguish from writer's cramp (focal hand dystonia) or essential tremor; some studies fail to demonstrate excessive overflow on EMG or abnormal cortical inhibition patterns, thereby hypothesizing that it is distinct from focal dystonia (Hai et al., 2010), while others suggest that it is a variant of essential tremor or a separate diagnosis entirely. PWT may occur sporadically or in the presence of a positive family history, is generally not progressive, and may be associated with a history of prior trauma in about 20% (Bain et al., 1995; Fasano et al., 2014; Hai et al., 2010) (see reviews Hai et al., 2010; Fasano et al., 2014).
Medical and Surgical Treatment of Tremors
2015, Neurologic ClinicsCitation Excerpt :Primary writing tremor is a condition in which tremor predominantly or only occurs during writing or also when adopting the hand position normally used for writing. More than half of the patients benefit from drug therapy (see Hai and colleagues81 for review). Another option is botulinum toxin,82 but there are no controlled trials.
Medical Treatment of Tremor
2011, Disease-a-MonthCitation Excerpt :Botulinum toxin injections are also helpful in these cases. In patients where the presentation is that of tremor without significant dystonia, propranolol and primidone may be effective.31 Holmes' tremor presents with components of rest tremor as well a postural tremor.
- ☆
The review of this paper was entirely handled by a Co-Editor-in-Chief, Zbigniew Wszolek.