Clinical Characteristics of Essential Tremor in South India: A Hospital-Based Cohort Study

Abstract

Introduction: Essential tremor (ET) is the most common adult movement disorder. Classic ET is characterized by action tremor of hands (95% cases), and tremor involving other regions is less common. Recent studies have revealed a few patients exhibiting nontremor features that include cognitive disorders, tandem gait abnormality, mood fluctuations, olfactory abnormality, hearing impairment, and sleep disorders. Very few studies on ET have so far been conducted in India, and the present study is a pioneering attempt to evaluate the clinical characteristics of patients diagnosed with ET. Materials and Methods: A standardized assessment protocol was used to collect data. Diagnosis of ET was established using consensus criteria established by the Movement Disorder Society. Tremor Research Group Essential Tremor Rating Assessment Scale was used to evaluate tremor impact. The severity of hand tremor was assessed by Glass Scale, and cognitive function was assessed by Mini–Mental Status Examination. Results: Out of the 45 patients enrolled, 73.3% were male and 26.6% were female, with a mean age of 44 ± 15 years. Postural tremor was observed in all, followed by intention tremor in 9 and rest tremor in 6 patients. Tremor of the hand was identified to be most predominant (100%). Voice tremor was observed in 15 (33.3%) patients and head tremor in 12 patients (26.6%) who were all females. Leg tremor was observed in 12 patients (26.6% of patients) and tongue tremor in 6 (13%) patients. Baseline asymmetry of tremor was observed in 60% of patients and positive family history in 35% of patients. The most common nontremor feature was tandem gait abnormality (40%). Moreover, most of the patients had Glass Scale II. Conclusion: Baseline asymmetry of tremor and male predominance were observed in the study. While hand tremor was the most common form of tremor, tandem gait abnormality was the most common nontremor feature as observed in patients with ET.

Essential tremor plus rest tremor: current concepts and controversies

“…Importantly, the prevalence of RT in ET has reported to be dependent on the recruitment setting, being the lowest in population-based setting and highest in a brain bank study (Louis et al 2015 ). In many (Rajalingam et al 2018 ; Bellows and Jankovic 2021 ; Campbell et al 2022 ; Prasad and Pal 2019 ; Peng et al 2022 ; Gilmour et al 2021 ; Steffen et al 2020 ), but not all studies (Pandey and Bhattad 2021 ; Manorenj et al 2019 ), ET + RT was among the commonest ET-plus subtypes.…”

Parkinsonism and tremor syndromes

“…Such additional signs have been noted to be present so frequently that the majority of ET patients in many studies have been classified as ET plus rather than ET [51][52][53][54]. Prevalence of rest tremor in patients with ET varies in different reports: 1.9% [55], 13.3% [56], 14% [57], 18.8% [58], 43.3% [53], and 46.4% [55]. Jaw tremor, classically present in PD, has been reported in 7.5% to 26.8% of patients with ET [59,60].…”

“…• Rest tremor can be present in 13.3 [56] to 46.4% of ET patients [55] • Parkinsonism can be seen in 20% of ET patients [63] • Kinematic studies have shown slower movements in ET without clear decrement [64] • ET-PD patients more likely to have asymmetric onset than ET patients [75] ET-Dystonia…”