Central auditory processing deficits in essential tremor

Central auditory processing (CAP) deficits are is emerging heterogeneous non-motor symptoms of essential tremor (ET). This study characterized CAP abilities of ET and examined correlations with tremor onset age and severity.

In this prospective cross-sectional study, CAP in ET participants was compared to age, gender, and education-matched healthy controls (HC). Tremor severity was assessed using Fahn-Tolosa-Marin rating scale. CAP was evaluated using the gap in noise (GIN) test, and auditory evoked potentials [Late latency response (LLR) and P300]. LLR parameters (P1-N1-P2-N2) were measured using speech stimulus at Cz, while P300 parameters (P3b) were recorded using both tonal & speech stimuli at Fz, Cz, and Pz.

ET participants showed significantly poorer GIN compared to HC. LLR revealed shorter N2 latencies, while P3b showed prolonged latencies and smaller amplitudes at Fz, Cz, and Pz for both tonal and speech stimuli. GIN parameters correlated with tremor onset and severity, while P3b (Fz) correlated with tremor onset age.

Findings indicate poor temporal resolution and higher cognitive sensory deficits in auditory processing in ET, implicating the involvement of multiple cortical and subcortical circuits.

These findings strengthen evidence of non-motor involvement in ET, highlighting auditory processing as a potential clinical attention.