Ramazzini and writer's cramp

A Clinical Profile of 125 Patients with Writer's Cramp

BACKGROUND

The characteristics of writer's cramp (WC) may vary according to native languages and scripts. We report the clinical profile of a large cohort of patients with WC from India.

METHODS

A chart review of 125 patients (F:M = 16:109) with WC seen over 10 years at the National Institute of Mental Health and Neurosciences (NIMHANS), India.

RESULTS

The mean age of patients was 36.8 ± 14.3, the mean age at onset (AAO) of symptoms was 31.5 ± 2.7 and the mean duration of difficulty in writing was 5.3 ± 6.3. The most common presenting complaint while writing was pain in the forearm (56%), followed by tremulousness of hand (28.8%) and abnormal posturing of hand (15.2%). Along with writing difficulty, 5.6% had difficulty in typing. The mean AAO of writing difficulty was significantly earlier in women than in men (22.8 ± 3.5 vs. 32.8 ± 4.2 years, p < 0.001). While writing, excessive extension (41.6%) of wrist was the most common abnormality, followed by excessive flexion (37.6%) and extension (19.2%) of index finger.

CONCLUSIONS

Women with WC have a significantly earlier age of onset than men. Excessive extension of wrist with flexion of thumb and index finger were the most common abnormalities noted in WC.

Motor overflow and mirror dystonia

Motor overflow is an unintentional muscle contraction which accompanies, but is anatomically distinct from the primary dystonic movement. This phenomenological nosology has not been systematically studied in focal hand dystonia (FHD). We conducted a prospective, case-control study to characterize motor overflow and mirror dystonia in patients with FHD. We compared the performance of 30 patients with FHD and 40 healthy controls on a variety of motor tasks, such as writing, drawing a spiral, straight line and a sine wave, repetitive wrist flexion-extension, finger tapping, hand grasping, hand pronation-supination, and a finger-to-nose task with each hand. The assessments were videotaped, the edited video segments were randomized, and an independent investigator who was "blind" to the subject's diagnosis rated the ipsilateral and contralateral overflow and mirror dystonia twice, 6 months apart. Using the mean of the two ratings, ipsilateral overflow was identified in 8.5 +/- 2.1 (28%) patients and in 1.5 +/- 0.7 (4%) controls (p < 0.001), contralateral overflow in 2.5 +/- 0.7 (8%) patients and in 1.5 +/- 0.7 (4%) of controls (p = 0.138), and mirror movement in 20.0 +/- 0.0 (67%) of patients and in 15.5 +/- 4.9 (39%) of controls (p = 0.001). There was a statistically significant correlation of dystonia and overflow score (Pearson's r 0.713, p < 0.001). The relatively high frequency of ipsilateral overflow and mirror dystonia in patients with FHD has both pathophysiological and therapeutic implications. In this study, the severity of dystonia was significantly correlated with motor overflow in multiple tasks.

Evidence for the effectiveness of botulinum toxin for writer's cramp

We performed a comprehensive literature search of clinical studies published between 1989 and 2007 concerning the use of botulinum neurotoxin (BoNT) in the treatment of writer's cramp (WC). Publications were categorized as Classes I-IV using the scale developed by the Therapeutics and Technology Assessment (TTA) subcommittee of the American Academy of Neurology. Our search resulted in 17 clinical publications discussing the treatment of WC with BoNT. The literature search results were: one publication being Class I, two being Class II, 11 being Class III, and three being Class IV.

Botulinum toxin: Clinical use

Since its development for the use of blepharospasm and strabismus more than 2.5 decades ago, botulinum neurotoxin (BoNT) has become a versatile drug in various fields of medicine. It is the standard of care in different disorders such as cervical dystonia, hemifacial spasm, focal spasticity, hyperhidrosis, ophthalmological and otolaryngeal disorders. It has also found widespread use in cosmetic applications. Many other indications are currently under investigation, including gastroenterologic and urologic indications, analgesic management and migraine. This paper is an extensive review of the spectrum of BoNT clinical applications.