Evaluation of psychoacoustic tests and P300 event-related potentials in elderly patients with hyperhomocysteinemia

Abstract

Introduction and objectives: Hyperhomocysteinemia as a risk factor for hearing impairment, neuronal damage and cognitive impairment in elderly patients is controversial and is limited by the small number of studies. The aim of this work was determine if elderly patients detected with hyperhomocysteinemia have an increased risk of developing abnormalities in the central auditory processes as compared with a group of patients with appropriate homocysteine levels, and to define the behaviour of psychoacoustic tests and long latency potentials (P300) in these patients.

Methods: This was a cross-sectional, comparative and analytical study. We formed a group of patients with hyperhomocysteinemia and a control group with normal levels of homocysteine. All patients underwent audiometry, tympanometry and a selection of psychoacoustic tests (dichotic digits, low-pass filtered words, speech in noise and masking level difference), auditory evoked brainstem potentials and P300.

Results: Patients with hyperhomocysteinemia had higher values in the test of masking level difference than did the control group (P=.049) and more protracted latency in P300 (P=.000).

Conclusions: Hyperhomocysteinemia is a factor that alters the central auditory functions. Alterations in psychoacoustic tests and disturbances in electrophysiological tests suggest that the central portion of the auditory pathway is affected in patients with hyperhomocysteinemia.

Keywords: Adulto mayor; Central auditory processing disorder; Desorden de procesamiento auditivo central; Elderly; Evoked brainstem auditory; Homocisteína; Homocysteine; P300 event-related potentials; Potenciales evocados auditivos de tallo cerebral; Potenciales relacionados a eventos P300.