Adults with dyslexia use internalized beat cues less than controls when estimating interval length

Abstract

Difficulties in both duration-based and beat-based time perception have been reported in individuals with dyslexia. It is also known that internalised beat cues may aid in the processing of durations. In the present study, we investigated whether the observed challenges in duration processing among individuals with dyslexia stem from their inability to utilise internal beat cues. Participants with vs. without dyslexia were asked to estimate the duration of intervals ranging from 500 ms to 10 s. In one condition (beat cue), participants listened to a sequence of 500 ms beats before the interval, and in the other they were exposed to silence (no beat cue), while their EEG was recorded. Beat cues enhanced the estimation of longer intervals and impaired that of shorter ones. Interestingly, the two groups did not differ in duration estimation performance, but they did differ in their utilisation of beat cues, with dyslexic adults showing less sensitivity to these, whether the impact was negative (cues before shorter intervals) or positive (before longer intervals). Additionally, the entrainment of brain waves to the target frequency (2 Hz) was significantly higher compared to entrainment to a non-target frequency (3.5 Hz), and cross-group differences were null. Our findings suggest that adults with dyslexia may have difficulties either in retaining the beat when it is no longer audible, or in using the internalised beat for duration estimation. Nevertheless, they seem capable of achieving the same estimation accuracy as neurotypical adults, possibly through compensatory strategies.