In a new study published in the April 2016 Journal of the American Academy of Audiology, Lindsey Jorgensen, AuD, PhD, of the University of South Dakota and Catherine Palmer, PhD, at the University of Pittsburgh found that reduced audibility significantly reduces scores on the Mini-Mental State Examination (MMSE), the most popular test used for determining cognitive function, resulting in greater apparent cognitive deficits and possible misdiagnosis of dementia.

The MMSE is used by over three-quarters of psychiatrists and has become a standard tool for front-line primary care physicians. However, research has shown that the MMSE has several structural weaknesses related to the orientation/positioning of the person being tested and their understanding of auditory language.

In their study, Jorgensen and colleagues enlisted 125 younger (mostly 18-year-old) normal-hearing adults who were randomly placed into 5 groups with varying degrees of simulated hearing loss: 1) normal hearing; 2) mild-to-moderately severe hearing loss; 3) mild-to-severe loss; 4) moderate-to-severe loss, and 5) severe-to-profound loss. The participants were blinded relative to what level of hearing loss they were simulating, and it was confirmed that decreasing audibility significantly reduced their speech intelligibility scores.

Results showed that Groups 1 and 2 were considered to have “normal cognitive function” (≥27) on the MMSE. However, Groups 3-5 had significantly poorer MMSE scores that correlated with poorer speech intelligibility. Groups 3-5 had scores of 16.84, 10.36, and 4.2, respectively. The authors write that “the majority of participants in this study who were provided with reduced audibility would have obtained a dementia diagnosis although participants were known to be cognitively intact.

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