Category: Ataxia
Objective: To describe the clinical and electrophysiological characteristics of tremor in SCA12.
Background: There is scarcity of literature on tremor of SCA12 patients which is the probably commonest type of autosomal dominant hereditary ataxia in northern India.
Method: 56 Genetically confirmed SCA12 patients (38M + 18F) were enrolled from Ataxia clinic at AIIMS, New Delhi. After detailed clinical evaluation, International Cooperative Ataxia Rating Scale (ICARS) and Fahan Tolosa Marin Tremor (FTM) rating Scale were used to evaluate the severity of ataxia and tremor in 51 patients. A bipolar surface EMG and accelerometer were used to evaluate tremor frequency, type, symmetry and pattern of muscle activation.
Results: The mean age (+SD) was 54.4+9.4 years (range 25-71) and mean age (+SD) at disease onset was 48.6+9.8 years. The number of CAG repeats ranged from 47 to 72 (median 56). Hand tremor was initial symptoms in 38 of 56 patients whereas tremor started unilaterally or bilaterally in 50% patients each. Mean score of ICARS and FTM rating score for 51 patients were 35.4 ±9.33and 45.0±18.2 respectively. Tremor was most commonly observed in hand (50/51) followed by the head tremor (24/51). Bilateral hand tremors were observed in 96% of patients. Tremor of lower limb (7/51) jaw (6/51), tongue (3/51), and face (1/51) were also present. Coexistent postural and intentional tremor was seen in 28/51 patients whereas coexistent postural, intentional and rest tremors in 12/51. The frequency of rest tremor ranged from 1.6Hz-10.8Hz whereas for postural tremor and intention tremor it was 2.1Hz – 9.8Hz. A synchronous pattern of muscle activation was found in 96% of SCA12 patients.
Conclusion: Although all three types of tremors (postural, intention and rest tremor) were observed, action tremor of hands was the most common type of tremor present in SCA12 patients Tremor showed synchronous pattern of muscle activation with average frequency of 4-5 Hz.
To cite this abstract in AMA style:
A. Srivastava, M. Narang, R. Rajan, M. Faruq. Electrophysiology and clinical description of Tremor in Spinocerebellar Ataxia 12 (SCA12) [abstract]. Mov Disord. 2022; 37 (suppl 2). https://www.mdsabstracts.org/abstract/electrophysiology-and-clinical-description-of-tremor-in-spinocerebellar-ataxia-12-sca12/. Accessed June 14, 2025.« Back to 2022 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/electrophysiology-and-clinical-description-of-tremor-in-spinocerebellar-ataxia-12-sca12/