The phonological Mismatch Negativity and P300 as diagnostic tools in stroke-related aphasia recovery: a longitudinal multiple case study

Abstract

ABSTRACT Background Recovery from stroke-related aphasia follows different stages, evolving from the acute and subacute phase (< 6 months post stroke) into the chronic phase (> 6 months post stroke). In general, phonology remains tenaciously disturbed, making it a relevant language marker to assess in every stage of recovery. The classical behavioural evaluation of phonological abilities in patients with aphasia can be extended with a registration of event-related potentials (ERPs), for example, the Mismatch Negativity (MMN) and the P300. ERPs have been suggested (1) to contain indications towards the language recovery progress (Nolfe et al. 2006. The role of P300 in the recovery of post-stroke global aphasia. European Journal of Neurology, 13(4), 377–384. https://doi.org/10.1111/j.1468-1331.2006.01237.x) and (2) to provide additional and (more) sensitive information along with the behavioural results (Aerts, Batens et al. 2015. Aphasia therapy early after stroke: Behavioural and neurophysiological changes in the acute and post-acute phases. Aphasiology, 29(7), 845–871. https://doi.org/10.1080/02687038.2014.996520). In this longitudinal study, we aimed to corroborate these previous findings. Methods and procedures In four patients with aphasia after a first-ever stroke, we administered behavioural language tasks as well as phonological ERPs in the (sub)acute and in the chronic stage of recovery. Outcomes and results The results demonstrate that the early presence of a P300 could be considered as an indicator of better recovery of language comprehension over time. For the MMN, such an indicative value remains to be confirmed. Moreover, abnormal ERP amplitudes or latencies accompanied behavioural ceiling effects in the chronic stage, suggesting a sensitivity of phonological ERPs for subtle language deficits that could not be detected by the established behavioural instruments. Conclusions The added values of phonological ERPs advocate their implementation in aphasia rehabilitation.