Auditory beat perception is related to speech output fluency in post-stroke aphasia

Abstract

Aphasia affects at least one third of stroke survivors, and there is increasing awareness that more fundamental deficits in auditory processing might contribute to impaired language performance in such individuals. We performed a comprehensive battery of psychoacoustic tasks assessing the perception of tone pairs and sequences across the domains of pitch, rhythm and timbre in 17 individuals with post-stroke aphasia and 17 controls. At the level of individual differences we demonstrated a correlation between metrical pattern (beat) perception and speech output fluency with strong effect (Spearman’s rho = 0.72). This dissociated from more basic auditory timing perception, which did not correlate with output fluency. This was also specific in terms of the language and cognitive measures, amongst which phonological, semantic and executive function did not correlate with beat detection. We interpret the data in terms of a requirement for the analysis of the metrical structure of sound to construct fluent output, with both being a function of higher-order “temporal scaffolding”. The beat perception task herein allows measurement of timing analysis without any need to account for motor output deficit, and could be a potential clinical tool to examine this. This work suggests strategies to improve fluency after stroke by training in metrical pattern perception.

Examining cortical tracking of the speech envelope in post-stroke aphasia

“…For example, Curtis et al (2020) reported that PWA with better rhythmic abilities were more likely to benefit from an additional rhythmic cue (hand tapping) in response to melodic intonation therapy. Similarly, Stefaniak et al (2021) found a correlation between the perception of rhythmic patterns and picture description fluency in PWA. The association between rhythmic measures and CTenv could help to understand rhythmic performance in aphasia in ways that can support candidacy and treatment response.…”

Is There a Role of Inferior Frontal Cortex in Motor Timing? A Study of Paced Finger Tapping in Patients with Non-Fluent Aphasia

“…Previous studies in patients with aphasia have reported deficits in temporal processing that might be related to lesions in Broca's region, such as the perception of rapid temporal patterns in speech sounds [26][27][28][29] and in non-speech auditory or visual stimuli [27,[30][31][32]. Recent evidence has shown that patients with non-fluent aphasia demonstrate poor temporal [33] and rhythm processing ability [34], as well, suggesting the possible role of central auditory processing in these performances and speech fluency, in general. In another study, left-brain-damaged patients with dysphasia were severely impaired in rhythm perception and production, implying the left hemisphere's specialisation in temporal processing and rhythm [35], which was also confirmed in a more recent study in which aphasic patients were evaluated in the reproduction of rhythmic patterns [36].…”