Effects of alprazolam on cortical activity and tremors in patients with essential tremor.

Abstract

BACKGROUND:

Essential tremor (ET) is characterised by postural and action tremors with a frequency of 4-12 Hz. Previous studies suggest that the tremor activity originates in the cerebello-thalamocortical pathways. Alprazolam is a short-acting benzodiazepine that attenuates tremors in ET. The mechanisms that mediate the therapeutic action of alprazolam are unknown; however, in healthy subjects, benzodiazepines increase cortical beta activity. In this study, we investigated the effect of alprazolam both on beta and tremor-related cortical activity and on alterations in tremor presentation in ET patients. Therefore, we characterised the dynamics of tremor and cortical activity in ET patients after alprazolam intake.

METHODS:

We recorded hand tremors and contralateral cortical activity in four recordings before and after a single dose of alprazolam. We then computed the changes in tremors, cortico-muscular coherence, and cortical activity at the tremor frequency and in the beta band.

RESULTS:

Alprazolam significantly attenuated tremors (EMG: 76.2 ± 22.68%), decreased cortical activity in the tremor frequency range and increased cortical beta activity in all patients (P<0.05). At the same time, the cortico-muscular coherence at the tremor frequency became non-significant (P<0.05). We also found a significant correlation (r = 0.757, P<0.001) between the reduction in tremor severity and the increased ratio of cortical activity in the beta band to the activity observed in the tremor frequency range.

CONCLUSIONS:

This study provides the first quantitative analysis of tremor reduction following alprazolam intake. We observed that the tremor severity decreased in association with an increased ratio of beta to tremor-related cortical activity. We hypothesise that the increase in cortical beta activity may act as a blocking mechanism and may dampen the pathological oscillatory activity, which in turn attenuates the observed tremor.

• Authors: Jaime Ibáñez, Jesús González de la Aleja, Juan A Gallego, Juan P Romero, Rosana A Saíz-Díaz, Julián Benito-León, Eduardo Rocon
• Journal: PloS one (PLoS One) Vol. 9 Issue 3 Pg. e93159 ( 2014) ISSN: 1932-6203 [Electronic] United States
• PMID: 24667763 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Alprazolam

Topics

• Alprazolam (pharmacology, therapeutic use)
• Brain (drug effects, physiopathology)
• Electromyography
• Essential Tremor (complications, drug therapy, physiopathology)
• Female
• Humans
• Male
• Middle Aged
• Muscles (drug effects, physiopathology)
• Tremor (complications, drug therapy)