Tapped out: do people with aphasia have rhythm processing deficits?

Purpose: In this study, the authors tested whether people with aphasia (PWAs) show an impaired ability to process rhythm, both in terms of perception and production.

Method: Two experiments were conducted. In Experiment 1, 16 PWAs and 15 age-matched control participants performed 3 rhythm tasks: tapping along to short rhythms, tapping these same rhythms from memory immediately after presentation, and making same-different judgments about pairs of tapped rhythms that they heard. Comparison tasks measured same-different judgment ability with visual stimuli and nonverbal working memory (Corsi blocks). In Experiment 2, 14 PWAs and 16 control participants made same-different judgments for pairs of auditory stimuli that differed in terms of rhythm or pitch (for comparison).

Results: In Experiment 1, PWAs performed worse than control participants across most measures of rhythm processing. In contrast, PWAs and control participants did not differ in their performance on the comparison tasks. In Experiment 2, the PWAs performed worse than control participants across all conditions but with a more marked deficit in stimulus pairs that differed in rhythm than in those that differed in pitch.

Conclusions: The results support the hypothesis that at least some PWAs exhibit deficits of rhythm and timing. This may have implications for treatments involving tapping or other rhythmic cues.