Cross-domain spontaneous tempo differences in adults with developmental dyslexia: Evidence from speech and gait

Background Developmental Dyslexia (DD) has historically been associated with phonological impairments though difficulties may be identified across cognitive and sensorimotor domains. The Temporal Sampling Framework proposed that atypical neural entrainment to temporal structure may underlie difficulties beyond phonological impairments in DD. However, tempo differences are inconsistently reported in the literature, particularly for ecologically valid, spontaneous motor tasks. Aims The present study examined whether university-aged adults with DD differ from skilled readers in spontaneous tempo across speech and gait domains, and whether any observed differences are consistent with domain-general or domain-specific accounts of timing in DD. Methods One-hundred and ten university students (52 with DD, 58 skilled readers) completed four self-paced tempo tasks, including oral diadochokinesis, text reading fluency, natural gait, and tandem gait. Kinematic analysis and audio recording were used to derive cadence and speech rate measures. Results Adults with DD produced consistently slower spontaneous tempo than skilled readers across all four tasks. These differences persisted when participants with sensorimotor comorbidity (DRSM, N = 14) were excluded from the DD group. Additionally, the DRSM group exhibited lower oral diadochokinetic rate than the DD group but performed similarly across the other tasks. Modest but significant positive correlations between speech and gait tempo were observed across the full cohort. Discussion These findings provide evidence for a cross-domain spontaneous tempo deficit in DD that is consistent with a partially domain-general model of timing impairment. The persistence of tempo differences into adulthood suggests that timing differences might reflect stable neurocognitive characteristics of DD.