Poster D17, Wednesday, August 21, 2019, 5:15 – 7:00 pm, Restaurant Hall
Poor action fluency performance is associated with reduced activity in motor and cognitive control regions in Parkinson’s disease
Noémie Auclair-Ouellet1,2,3,4,5, Alexandru Hanganu3,4,5,6, Erin Mazerolle4,5,7, Stefan Lang4,5, Mekale Kibreab4,5, Mehrafarin Ramezani4,5, Tazrina Alrazi4,5, Tracy Hammer4,5, Jenelle Cheetham4,5, Iris Kathol4,5, Bruce Pike4,5,7,8, Justyna Sarna4,5, Davide Martino4,5, Oury Monchi4,5,9,10;1School of Communication Sciences and Disorders, Faculty of Medicine, McGill University, 2Centre for Research on Brain, Language and Music, Montreal, 3Centre de recherche de l'Institut universitaire de gériatrie de Montréal, 4Department of Clinical Neuroscience, Cumming School of Medicine, University of Calgary, 5Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 6Département de psychologie, Faculté des arts et des sciences, Université de Montréal, 7Department of Radiology, Cumming School of Medicine, University of Calgary, 8Medical Physics Unit, Faculty of Medicine, McGill University, 9Department of Neurology and Neurosurgery, McGill University, 10Département de radiologie, Faculté de médecine, Université de Montréal
Introduction: The processing of action words is thought to depend on motor semantic features and motor regions. However, compared to other types of words, action words are considered to be more demanding in terms of cognitive resources. Patients with Parkinson’s disease (PD) have motor symptoms and executive functions difficulties, making them vulnerable to action word processing deficits. This study investigated the clinical, behavioural and neural correlates of action word processing deficit in PD. Methods: 48 idiopathic PD and 38 control participants were recruited. PD participants with a performance one standard deviation below the norm or lower on the action fluency test were identified (n = 15). All PD participants with a poor performance (PD-P) were male. They were compared to male PD participants with good performance (PD-G) (n = 19) and male controls (n = 16). All participants had an evaluation of their motor symptoms (UPDRS-III) and completed a comprehensive neuropsychological battery. Behavioural measures were analysed with one-way ANOVAs (alpha = 0.05). Participants also completed an fMRI version of the Wisconsin Card Sorting Test (WCST). The WCST requires learning and shifting between sorting rules based on feedback received after each trial. In this version of the test, participants are trained prior to scanning and feedback (correct or incorrect) is provided as change in screen brightness. The contrast between receiving a negative feedback and receiving a positive feedback represents the planning of a set-shift and has been associated with frontostriatal activation. Group differences were analysed with permutation analysis (FSL randomise; 5,000 permutations; TFCE: alpha = 0.05). Results: Motor symptoms were not different between PD groups. Action fluency performance was significantly poorer in PD-P compared to PD-G and controls, but there was no difference between PD-G and controls. The same pattern was observed for letter fluency, while there was no difference between groups on animal fluency, naming, and sentence comprehension. PD-P had a significantly lower performance than PD-G and controls on an executive composite score. However, when dividing measures into verbal and non-verbal executive composite scores, there was a significant difference between PD-P and PD-G, and between PD-P and controls on the verbal executive score, but no difference on the non-verbal executive score. On the WCST, PD-P completed less sorting rules and were slower on average than PD-G and controls, but there was no difference between PD-G and controls. During the planning of a set shift, PD-G had greater activity than PD-P in the left orbitofrontal region, middle temporal gyrus and temporo-parietal junction, occipital lobe and putamen. Controls had greater activity than PD-P in those regions, the cerebellum and the caudate nucleus. Discussion: Action word deficit was not associated with more severe motor symptoms in PD. However, it was associated with difficulties in verbal executive function tests and reduced activity in regions associated with executive functions, cognitive control for language, and motor control. The reliance of action words on complete motor plans rather than motor features and the effect of sex on action word processing in PD should be further investigated.
Themes: Disorders: Acquired, Meaning: Lexical Semantics
Method: Functional Imaging