Systemic high blood pressure and inner ear dysfunction: a preliminary study.

OBJECTIVE: To assess the association between inner ear dysfunction and retinal vascular changes related to systemic arterial hypertension.

DESIGN: A comparative, cross-sectional and observational study.

SETTING: Primary care.

MAIN OUTCOMES MEASURES: Hearing and vestibular symptoms evaluated by a standardized questionnaire; cochlear function evaluated by audiometry and distortion product otoacoustic emissions; vestibular function evaluated by oculomotor and bithermal caloric tests and vascular retinal compromise evaluated by ophthalmoscopy (according to the modified Scheie classification).

RESULTS: Forty-two subjects participated in the study, 21 with and 21 without arterial hypertension, age and sex matched; with no history of diabetes mellitus and with normal glucose levels and normal blood lipids. Although patients with hypertension reported vertigo more frequently than control subjects, conventional oculomotor and bithermal caloric tests showed no difference between the two groups. Patients with hypertension showed deterioration of hearing thresholds at 8 kHz and, compared with normotensive subjects, a higher frequency of abnormal otoacoustic emissions (P = 0.01). According to Scheie classification, 43% (95% CI: 33-53%) of the patients showed second degree retinal vascular compromise and 24% (95% CI: 15-33%) of them showed first degree compromise. The degree of the vascular retinal compromise was significantly correlated with the hearing thresholds at 8 kHz (Spearman's correlation coefficient 0.45, P = 0.002) and it was also consistent with the absence of otoacoustic emissions at frequencies between 4 and 8 kHz.

CONCLUSION: The results of this preliminary study suggest that patients with systemic arterial hypertension may have cochlear dysfunction associated with the vascular disease because of hypertension, which could be silent and without clear evidence of vestibular dysfunction.