Slide Slam L11
Greater gyrification of right Heschl’s gyrus is related to better auditory language comprehension in patients with left hemisphere stroke
Letitia M. Schneider1,2,3,4, Josue L. Dalboni da Rocha3, Cathy J. Price5, Narly Golestani1,2,3,4; 1Brain and Language Lab, Cognitive Science Hub, University of Vienna, Vienna, Austria, 2Dept of Behavioral and Cognitive Biology, Faculty of Life Sciences, University of Vienna, Vienna, Austria, 3Department of Psychology, Faculty of Psychology and Educational Sciences, University of Geneva, Geneva, Switzerland, 4Department of Cognition, Emotion and Methods in Psychology, Faculty of Psychology, University of Vienna, Vienna, Austria, 5Wellcome Centre for Human Neuroimaging, Institute of Neurology, University College London, London, United Kingdom
In aphasic patients with left hemisphere stroke, better auditory language comprehension has been associated with (i) activation of areas anterior to right auditory cortex (Crinion & Price, 2005; Wilson & Schneck, 2021) and (ii) higher grey matter volume in right middle temporal gyrus (Lukic et al., 2017). A structural index that hasn’t been investigated in association with outcome after stroke is gyrification of the auditory cortex. Greater gyrification of left Heschl’s gyrus (HG), which includes the primary auditory cortex, has been linked to better non-native speech sound learning (Golestani et al., 2007) and to phonetic expertise (Golestani et al., 2011), and greater gyrification of right HG has been related to higher language aptitude (Turker et al., 2017). It remains to be seen how the degree of gyrification in HG of aphasic stroke patients relates to auditory language comprehension. We examined the relationship between right HG morphology and auditory language comprehension in left hemisphere stroke patients. 20 chronic stroke patients (mean age=54 years, SD=12, 2 females) with 100% damage to the left auditory cortex were selected for whom we had structural MRI data and comprehensive aphasia test (CAT) behavioural scores. Performance on a spoken paragraph comprehension task was evaluated. T1’s were processed with Freesurfer v.5.3 and the Toolbox for Automated Segmentation of Heschl’s gyrus (TASH) (Dalboni da Rocha et al., 2020), to automatically label right HG. The TASH HG labels were then used to visually (i) classify the gyri (single vs. common stem duplication) and (ii) determine the degree of gyrification, with higher values corresponding to a longer intermediate sulcus. Ratings were performed independently by two authors and showed a high correspondence (r=0.96). A partial correlation between the gyrification measure and spoken paragraph comprehension task was performed. 14/20 patients scored below the normal range on the spoken paragraph comprehension task. Right HG common stem duplication was observed in 5/6 (83%) of patients with normal paragraph comprehension, but only in 3/14 (~20%) of patients with aphasic scores. This difference is significant (p = 0.018, Fisher’s exact test). Further, there was a positive correlation between gyrification of right HG and spoken paragraph comprehension (r(18)=.66, p=.01), when controlling for age at stroke, gender, lesion volume, years of education, months since stroke, native language, and scanner. The findings of the present study are the first to show a positive association between gyrification in the right HG and auditory language comprehension in stroke patients with lesions to the left auditory cortex. The observed behavioural advantage of greater gyrification is in line with previous findings in language experts (Golestani, et al. 2011) and in relation to language aptitude (Turker et al., 2017). Although this is a cross-sectional study, it might be that the observed gyrification differences are not due to plasticity after stroke, but rather reflect pre-morbid differences due to the likely relative stability of auditory cortex morphology (Chi et al., 1977). Next steps include replicating our visually determined gyrification results with those derived from a novel automated toolbox (Dalboni da Rocha et al, in preparation).