Intermittent tinnitus-an empirical description

Tinnitus is often classified into acute or chronic persistent forms. However, epidemiologic studies have shown that intermittent tinnitus (IT), which does not clearly belong to either category, is the most common form.

The aim of this study was to further characterize IT empirically.

We conducted an exploratory cross-sectional interview study among 320 subjects with tinnitus. Sociodemographic and tinnitus characteristics, concomitant complaints, perceived triggers, and help-seeking behavior were assessed. Subjects were classified into continuous (CT), IT, or single-episode tinnitus (SET) if they had experienced tinnitus "continuously," "temporarily time and again," or "only once but for several days," respectively, during the past 12 months.

Of the sample, 62% reported IT, 23% SET, and 16% CT. Mean time since onset was 36 (CT), 28 (IT), and 19 months (SET), respectively. Most subjects with IT experienced episodes lasting a few days, whereas in 25%, episodes lasted 1-4 weeks. Mean duration was 1.6 weeks. The frequency of IT episodes ranged from every few days to half-yearly; mean frequency was every 7 weeks. Leading triggers were occupational and private stress. Asthenia, depression, social isolation, psychiatric disorders, and inner ear disorders were more prevalent among CT than IT subjects. Help-seeking behavior was comparable between CT and IT.

IT is associated with emotional reactions and situational impairment severe enough to trigger multiple treatment attempts, but usually does not result in severe impairment. Inner ear disorders and psychological changes are less frequent than in CT; therefore, treatment response and prognosis might be better. We suggest classification of tinnitus into acute single-episode (<3 months), intermittent, or chronic persistent (>3 months) forms.