A comparison of auditory and vestibular dysfunction in Parkinson's disease and Multiple System Atrophy

Introduction: Vertigo and disequilibrium are common symptoms in idiopathic Parkinson's disease (PD) and in Multiple System Atrophy (MSA). Hearing loss has been recently recognized as an additional non-motor feature in PD. The aim of this study is to evaluate audio-vestibular function in patients affected by PD and MSA. Methods: Fifteen patients with PD, 16 patients with MSA and 20 age-matched healthy controls (HC) were enrolled. Audio-vestibular examination included pure-tone audiometry (PTA), vestibular bed-side examination, video Head Impulse Test (vHIT), and cervical Vestibular-Evoked Myogenic Potentials (cVEMPs). Results: PD and MSA patients showed worse PTA thresholds compared to HC at high frequencies. MSA patients showed worse PTA thresholds at 125 Hz compared to HC. In patients with PD, a direct correlation between disease duration and PTA thresholds was found at 2000 Hz and 4000 Hz. In patients with MSA, disease duration was directly related to PTA thresholds at 125 Hz and 250 Hz. Among PD patients, cVEMPs were absent bilaterally in 46.7% and unilaterally in 13.3% of the subjects. Among MSA patients, cVEMPs were absent bilaterally in 26.7% and unilaterally in 40% of the subjects; p13 latency was significantly increased in PD patients as compared to HC. A significant inverse relationship was found between disease duration and cVEMP amplitude in MSA patients. Conclusion: We found that high-frequency hearing loss and cVEMP abnormalities are frequent features of both MSA and PD, suggesting that an audio-vestibular dysfunction may be present in these patients even in the absence of self-reported auditory or vestibular symptoms.