Lateralized neuroleptic-induced side effects are associated with asymmetric visual evoked potentials

Area of Science:

• Neuroscience
• Psychopharmacology
• Clinical Electrophysiology

Background:

• Neuroleptic medications are known to potentially impact cerebral hemispheres asymmetrically.
• This asymmetry may manifest as lateralized extrapyramidal side effects and altered electrophysiological measures.
• Previous research indicates a link between drug effects and hemispheric differences.

Purpose of the Study:

• To investigate the association between visual evoked potential (VEP) asymmetry and the lateralized presentation of neuroleptic-induced parkinsonism or tardive dyskinesia (TD).
• To determine if VEP asymmetry can serve as an indicator of differential hemispheric drug effects.

Main Methods:

• Assessed asymmetry of later visual evoked potential (VEP) component amplitudes.
• Compared VEP asymmetry in patients with lateralized side effects, symmetrical side effects, and no extrapyramidal side effects.
• Utilized electrophysiological recordings to measure brain responses to visual stimuli.

Main Results:

• Patients exhibiting lateralized extrapyramidal side effects (n=8) showed significantly greater VEP amplitude asymmetry compared to those with symmetrical side effects (n=6) or no side effects (n=11).
• Later VEP components were particularly indicative of this asymmetry.
• The findings suggest a correlation between electrophysiological asymmetry and clinical presentation of side effects.

Conclusions:

• VEP asymmetry is significantly associated with the lateralized occurrence of neuroleptic-induced parkinsonism and tardive dyskinesia (TD).
• This electrophysiological measure may reflect the differential impact of neuroleptic medication on the two cerebral hemispheres.
• VEP asymmetry could be a valuable biomarker for predicting or understanding lateralized drug side effects.