Subtle Cerebellar Features in Relatives of Essential Tremor Cases

Area of Science:

• Neurology
• Genetics
• Movement Disorders

Background:

• Essential tremor (ET) is frequently associated with mild cerebellar signs.
• Previous research indicates that unaffected relatives of ET patients may display preclinical disease features.
• The cerebellum's role in ET pathophysiology is increasingly recognized.

Purpose of the Study:

• To quantitatively assess subtle cerebellar signs in first-degree relatives of ET cases.
• To investigate if these signs correlate with the tremor severity of the ET proband.
• To explore potential early subclinical markers of ET.

Main Methods:

• Two hundred sixty-nine first-degree relatives of ET cases without tremor were recruited.
• Participants were stratified into groups based on tremor severity (Total Tremor Score - TTS).
• Neurological examinations quantified gait, balance, and intention tremor.

Main Results:

• Relatives with higher TTS demonstrated poorer performance in tandem stance and stance with feet together.
• Increased intention tremor in both arms and legs was observed in individuals with higher tremor scores.
• A significant association was found between higher TTS and impaired balance and increased intention tremor.

Conclusions:

• Subtle cerebellar signs, specifically balance impairments and intention tremor, are more prevalent in first-degree relatives of ET cases with greater tremor severity.
• These findings suggest a potential subclinical stage of essential tremor in these relatives.
• This research contributes to understanding the early, preclinical manifestations of ET and its link to cerebellar dysfunction.