Dichotic Digits Test Performance Across the Ages: Results From Two Large Epidemiologic Cohort Studies.
Mary E Fischer, Karen J Cruickshanks, David M Nondahl and 6 others
PMID 27941404WHAT IT FOUND
Across 3655 adults, free recall Dichotic Digits Test scores varied widely and were lower with older age, male sex, lower education, worse hearing and cognitive impairment; right ear directed recall was often 100% correct.
Key findings
01The mean free recall score was 76.7% correct, and scores ranged from 21.3% to 100%.
02On right ear directed recall, 69% of participants scored 100% correct, and 15% missed 2 or more digits.
03Older age, male sex, less education, moderate or marked hearing loss, and cognitive impairment were each associated with lower adjusted free recall scores.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study was cross-sectional, so it cannot show whether scores changed over time or whether low scores cause or result from cognitive decline. Cognitive impairment was defined only by an MMSE score below 24 out of 30, or reported dementia or Alzheimer's disease, and participants under age 50 were assumed not impaired. Right ear directed recall had very limited variability, with 69% of participants scoring 100% correct. The five factors in the model accounted for 22.7% of the spread in free recall scores, leaving much of the variation unexplained. Some participants did not complete the DDT because of hearing severity or asymmetry, failed training, or requesting to stop: 158 in the EHLS and 82 in the BOSS. Only right ear directed recall was performed, not left ear directed recall.
The easy way to misread this
Do not treat the right ear directed recall score as a measure that separates people well in this population. It had very limited variability, with 69% of participants scoring 100% correct.