Auditory and vestibular dysfunction in patients with Parkinson's disease

Background Motor dysfunction in patients with Parkinson disease (PD) is just the tip of the iceberg. Auditory and vestibular dysfunction in patients with PD gained much attention owing to them being one of the nonmotor symptoms. Aim To explore abnormalities of pure tone audiometry (PTA), brainstem auditory evoked potentials (BAEPs), vestibular evoked myogenic potential (VEMP), and videonystagmography (VNG) in patients with PD and their correlation with motor and cognitive dysfunction. Patients and methods The study was conducted on 20 patients with PD and 15 controls. Selected patients were subjected to evaluation of motor symptoms using Unified Parkinson's Disease Rating Scale (UPDRS) and cognitive function using Parkinson disease-Cognitive Rating Scale (PD-CRS). PTA, BAEPs, cervical VEMPs, and VNG were carried out for all patients and controls. Results Patients with PD show higher mean hearing thresholds at all PTA frequencies in both ears than controls. Analysis of BAEP demonstrated that patients with PD have significantly prolonged absolute latencies of wave Ill and wave V and interpeak latencies of I-III and I-V in both ears than controls. VEMP findings revealed that patients have significantly delayed P13 and N23 latencies and smaller P13-N23 amplitude in both ears than controls. VNG findings showed canal paresis in 60% of patients with PD and nystagmus in 60% of patients with PD. Correlative results revealed statistically significant correlations between VEMP parameters and UPDRS as well as PD-CRS, but there were no statistically significant correlations between PTA frequencies or BAEP latencies and UPDRS or PD-CRS. Conclusion Auditory and vestibular dysfunction is common in PD but cannot be totally correlated with the motor and cognitive symptoms.