Do individuals with bothersome tinnitus have different auditory selective attention and working memory abilities compared to non-tinnitus controls? — an exploratory study
Degree GrantorUniversity of Canterbury
Degree NameMaster of Science
Tinnitus is the perception of sounds heard in the ears or head in the absence of an external sound source (Luck, 2005; Stephens, 1987). Most individuals with tinnitus are able to habituate to the tinnitus signal and notice it to a lesser degree, while the sound remains salient for others (Coles, Baskill, & Sheldrake, 1984). Research has pointed to the persistence of tinnitus sounds as an abnormal response of the central auditory system (Noreña & Farley, 2013). Tinnitus has been frequently linked with reduced cognitive function (Andersson, Lyttkens, & Larsen, 1999; Jacobson et al., 1996; Stevens, Walker, Boyer, & Gallagher, 2007; Wilson, Henry, Bowen, & Haralambous, 1991) and working memory deficits (Hallam, McKenna, & Shurlock, 2004; Rossiter, Stevens, & Walker, 2006). Research has shown that tinnitus can also have an impact on auditory selective attention (Andersson, Eriksson, Lundh, & Lyttkens, 2000), with patients reporting difficulties with concentrating due to their tinnitus (Andersson et al., 1999). The aim of this study was to characterise and compare auditory selective attention and working memory ability in individuals with tinnitus against healthy, non-tinnitus controls, and investigate the relationship between cognitive abilities, self-perceived tinnitus impact on functional life, and severity of tinnitus. Twenty tinnitus participants and 22 control participants age 21 to 75 years completed the study. Tinnitus participants completed the following questionnaires: Tinnitus Sample Case History Questionnaire (TSCHQ) (Langguth et al., 2007), Tinnitus Functional Index (TFI) (Meikle et al., 2012), Tinnitus Severity Numeric Scale (TSNS) (The Tinnitus Research Initiative, 2009) and the Tinnitus Handicap Inventory (THI) (Newman, Jacobson, & Spitzer, 1996). Participants also underwent tinnitus characterization procedures to obtain psychophysical measurements of tinnitus: pitch, loudness, and minimum masking levels. All participants received audiometric assessment to determine hearing threshold levels, completed the Depression, Anxiety, Stress Scale (DASS) (Lovibond & Lovibond, 1996), and were screened for dementia using the Mini Mental State exam (MMSE) (Folstein & Folstein, 1975). Auditory selective attention was assessed via a brief, computerised dichotic listening task adapted from the protocol employed by Humes, Lee, and Coughlin (2006) using Millisecond Inquisit Lab software (Draine, 2015). This software was also used to administer forward and backward order auditory digit span tasks, indexing short-term and working memory abilities. Findings revealed no between-group differences in auditory selective attention or digit span performance. However, significant negative correlations were found within the tinnitus group between a digit span task determining the maximum length of numbers recalled in forward order and TSNS sub-scales indicating tinnitus discomfort (rs = -.614, p = 0.004) and annoyance (rs = -.566, p = 0.009) as well as the TFI overall score (rs = -.536, p = 0.015). Tinnitus group TFI scores were also significantly correlated with the DASS stress sub-scale, rs = 0.448, p = 0.048. The lack of between-group differences detected indicate that tinnitus participants do not appear to differ in auditory selective attention and working memory abilities compared to the control group, for this study. However, higher degrees of self-reported overall tinnitus functional impact, and specific subsets of discomfort and annoyance were associated with poorer short-term memory ability, as indexed by the forward-order digit span task. Previous research has demonstrated atypical neural indicators of short-term memory for individuals with tinnitus, as compared to controls (Husain, Akrofi, Carpenter-Thompson, & Schmidt, 2015; Husain, Pajor, et al., 2011). A positive correlation revealed between TFI overall scores and stress lends further support to the relationship between tinnitus and negative emotional states. Due to a lack of international consensus on the links between tinnitus and cognitive processes of attention and memory (Andersson & McKenna, 2006; Mohamad, Hoare, & Hall, 2015), and limitations of study power and lack of well-matched groups in the current study, further examination is recommended. Tinnitus remains an incurable symptom, but future research with better-designed studies may help to shed further light on tinnitus and cognitive processes—specifically short-term memory—and help inform tinnitus management practice.