Dynamics of controlled phonological and free oral verbal associations in persons with efferent motor aphasia in the process of speech rehabilitation in the modelled sensory-enriched environment

Abstract

In this study we conducted a comparative analysis of the dynamic changes in quantitative and structural parameters of free and directed phonological associations in two groups of right-handed patients diagnosed with efferent motor aphasia and undergoing different types of speech rehabilitation. Both groups participated in a six-week course of speech therapy. The main group (N=29) underwent speech recovery in a simulated sensorily enriched environment (sensory speech therapy), while the control group (N=24) followed a traditional approach to aphasia rehabilitation. The duration of aphasia ranged from 4 to 6 years. The focus of brain activation created by the sensorily enriched environment was determined by the lesion location, duration of brain damage, and aphasia type, aiming to enhance intra- and inter-hemispheric multisensory interactions. We examined the productivity of associations, the level of verbal perseverations, the stability of association pace, semantic flexibility and organization, types of semantic organization in the associative series, and phonological strategies. Comparison of pre- and post-conditions revealed that both types of speech therapy had a positive effect, improving the productivity of free associations and reducing the level of verbal perseverations. In addition to these general improvements, speech recovery in the simulated sensorily enriched environment exhibited several specific characteristics. Compared to the traditional approach, the sensorily enriched environment contributed to the creation of normotipic foci of brain activation relevant to speech processes. This accounted for its more pronounced influence on both quantitative and structural parameters of free and directed associative series. Sensorily enriched environment not only increased the productivity of free associations, a characteristic shared with traditional therapy, but also of directed associations. It also enhanced the stability of the pace of free associations and the meaningfulness of its associative chains. In oral phonological verbal associations during sensory therapy, the frequency of using the syllabic strategy increased, indicating improved flexibility of regulatory speech processes and auditory-verbal memory created by the simulated sensorily enriched environment.