Slower processing, speech recognition and cognition in aging.

With aging, individuals experience a decreased ability to recognize speech, even when they have normal hearing acuity. This difficulty is more obvious when the speech is presented at a fast rate or is presented in the presence of competing signals. Two of the possible underlying mechanisms for poor speech recognition in older individuals include reduced speed of signal processing within the auditory pathways and/or reduced cognition. Parts 1 and 2 of this series of articles presented evidence showing slower processing within the higher auditory pathways and its relationship to speech recognition.1,2

Age-related changes in brain structure and function may contribute to poor sensory and cognitive function. Alternatively, cognitive declines may be a consequence of degraded auditory processing, causing sensory deprivation. Thus, a complex inter-relationship among speech recognition, cognitive performance, and slower processing can be expected. Part 3, the final article in the series, examines this complex inter-relationship. An in-depth understanding of these relationships can be expected to lead to more effective aural rehabilitation services for older individuals.