Characteristics of language and communication after subcortical lesions in the left and right hemisphere

Research

Objectives: The present case comparison investigates to our knowledge for the first time, whether the dichotomy of specific linguistic and communicative characteristics following left and right hemisphere cortical lesions can also be demonstrated after subcortical damage. Classically, left hemisphere cortical lesions of language-relevant areas cause aphasia (Raymer & Rothi, 2018), with cardinal symptoms on a microlinguistic level (e.g. phonologic and semantic errors). Damage to right-hemisphere cortical areas typically results in Cognitive Communication Disorders (CCDs) (Blake, 2018). Symptoms of CCDs are mainly evident on a macrolinguistic level (e.g. tangentiality, verbosity).

Design: Systematic single-case comparison. Setting: Neurological rehabilitation clinic. Participants: Two persons with comparable subcortical lesions after postacute left (Patient A) and right (Patient B) basal ganglia hemorrhage stroke. Patient A: Anomic aphasia (Huber et al., 1983), fluent spontaneous speech, short, syntactically simple sentences, word-retrieval problems. Patient B: CCD (Quinting et al., 2020), fluent spontaneous speech, complex, partially paragrammatic syntax. Interventions: Participants were assessed for communicative-pragmatic ability using the ANELT (Blomert et al., 1994; Rubi-Fessen et al., 2021). Responses were analyzed with regard to linguistic and communicative-pragmatic aspects. A linguistic evaluation was performed by computer-assisted software 'Aachen spontaneous speech analysis' (ASPA, Huber et al., 2005). Main Outcome Measures: A-scale of the ANELT and linguistic parameters of ASPA.

Results: The results of the ANELT-A-scale were comparable for both patients (Patient A: 84/100, Patient B: 81/100 points). On a microlinguistic level, Patient A showed phonematic paraphasias; ASPA analyses revealed deviations from normative data from non-brain-damaged speakers (Hussmann et al., 2012) concerning all parameters except for type-token-ratio. Patient B´s reactions were syntactically complex and less coherent, indicating problems on a macrolinguistic level. However, ASPA analyses showed results slightly below average concerning percentage words and type-token-ratio.

Conclusions: Typical linguistic-communicative characteristics of cortical left- and right-hemispheric lesions may appear equivalently in left- and right hemispheric subcortical damage. With comparably good communicative effectiveness in the ANELT, these characteristics can also be shown quantitatively by specific patterns in spontaneous speech parameters in ASPA analyses. Author(s) Disclosures: All authors report no conflicts of interest.