Clinical and Neurophysiological Study of Non-Parkinsonian Tremor.

Tremor is a periodic movement about an axis, which distinguishes it from other movement disorders such as chorea, myoclonic jerks and tics which may not have a fixed period and may involve complex movements other than simple oscillation .Tremors present commonly in neurology OPD. Among these, majority of cases are Parkinsonian tremors, however non-parkinsonian tremors eg. Essential tremor, Exaggerated physiological tremor, drug induced tremor, rubral tremor, dystonic tremors etc are also seen. Essential tremors is one of the most common movement disorders. In population based studies, the prevalence of ET increases steadily with age, occurring up to in 10% of patients older than age 60 years with a median age of 15 years but there is a bimodal distribution. Tremors can be divided into two types – at rest and those seen on action. ‘Rest’ is only a relative term as some slight tonic postural maintenance is often required. Action tremors must be subdivided into those seen just with postural maintenance (postural or static tremor) and those requiring goal directed movements (intentional or kinetic tremor). A third division of action tremor is those seen only with specific types of kinetic movements such as hand writing. 1. Eighty eight patients with non-parkinsonian tremors were studied with a sex distribution of male 59.1 per cent and females 40.9 per cent. 2. Age of the studied population was ranged from 14-76 with mean age of 42.63 years. 3. Essential Tremor was the most common non-parkinsonian tremor found in our study (59.1 per cent). 4. Dystonic tremor was being the second most common non-parkinsonian tremor found in our study. 5. Enhanced physiological, rubral, task specific, cerebellar, drug induced and alcohol withdrawal were the other types of non-parkinsonian tremors seen. All types of EMG burst activity was seen in such patients. 6. The mean TRS score was 11.02 ± 5.36 SD with a range of 3.5 – 24. 7. We observed that alcohol responsiveness could not be used as a diagnostic criterion for ET in India, as many patients are teetotalers. 8. The Rest tremor ET was associated with disease that was more severe, more disseminated (extending to other body regions), and of longer duration. 9. Positive family history was found in 24 out of the 52 (46.5 per cent) ET patients, it was definite in 4, probable in 15 and possible in 6 patients. 10. Three types of burst activity in EMG analysis were seen in our study namely synchronized, mixed and alternating pattern. 11. Classical synchronized EMG burst pattern was observed in 76.9 per cent ET patients (p-0.011) with mean frequency of 9.69 ± 3.06 Hz. Such ‘fast frequency’ ET can be differentiated from enhanced physiological tremor using synchronized surface EMG burst pattern