The clinical characteristics of tinnitus in patients with vestibular schwannoma.

OBJECTIVES

To review the symptoms, signs, and clinical findings in a large series of patients diagnosed with unilateral sporadic vestibular schwannoma (VS) to describe the clinical characteristics of tinnitus in this population. Further, to ascertain which of the proposed mechanisms of tinnitus generation in VS was supported.

DESIGN

Retrospective case note and database review.

SETTING

Tertiary university teaching hospital departments of audiology and neuro-otology.

PARTICIPANTS

Nine hundred forty-one patients with unilateral sporadic VS, diagnosed during the period 1986 to 2002. Twenty-three additional patients were excluded due to missing clinical data.

MAIN OUTCOME MEASURES

The presence or absence of tinnitus, and its rated subjective severity were analyzed in conjunction with data regarding patient demographics, symptoms, signs, and diagnostic audiovestibular test findings.

RESULTS

No statistical association at the 5% level was found between tinnitus presence/absence and patient age, gender, 2- to 4-kHz audiometric thresholds, ipsilateral auditory brainstem response abnormality, length of history, tumor side, nor caloric test abnormality. Statistically significant associations were found between tinnitus presence/absence and tumor size (p = 0.012) and type of hearing loss (progressive, sudden, fluctuant, nil) with a tendency for patients without hearing loss to be less likely to experience tinnitus. Statistically significant associations were identified between classification of tinnitus severity and age at diagnosis (p < 0.001) (greater age being associated with greater tinnitus severity), abnormal findings on caloric testing (p = 0.01) (abnormal calorics being associated with greater tinnitus severity), and tinnitus as a principal presenting symptom (p < 0.001) (this being associated with greater tinnitus severity).

CONCLUSIONS

The analysis does not identify any single one of the proposed mechanisms for tinnitus as being the obvious culprit. In fact, even in a homogeneous group of patients such as this, there is evidence of multiple mechanisms that are not mutually exclusive. The association between increased tinnitus severity in older patients, patients with canal pareses on caloric testing, and with tinnitus as a principal presenting symptom should be borne in mind by the clinician.