Object. Selective deficit of verb (V) vs. noun (N) processing has been consistently reported in the motor neuron disease – frontotemporal dementia (MND-FTD) complex. Prerolandic regions atrophy has been traditionally thought to account for N-V dissociation in the MND-FTD complex via selective action semantics impairment (Embodied Cognition Theory, ECT). Nonetheless, explanations pertaining to both sensitivity of those regions to morpho-phonological structure of Vs and executive functioning (EF) contribution have not been endorsed. The aims of this study was to both assess neurocognitive mechanisms underlying N-V dissociation in MND patients and validate its cognitive diagnostic role in this population. Materials. Thirty consecutive MND patients and 29 healthy controls were recruited. Patients’ clinical features (disease duration; site of onset; bulbar signs) and both neuropsychological (Edinburgh Cognitive and Behavioral ALS Screen, ECAS) and functional outcomes were considered. Methods. The two groups were compared on tasks evaluating N and V lexical retrieval, object- and action-semantics, and V lexical-morphosyntactic implementation, while controlling for EF measures. Effects of motor feature degree (actionality) and lexical-morphosyntactic complexity of items on lexical retrieval were assessed via logistic linear mixed models; between-groups comparisons were implemented via overdispersed linear models. Clinical relevance of N-V dissociation was investigated by assessing its association with disease-related variables. Results. Both groups performed worse in V than in N naming. Patients performed worse than controls in V naming and both object- and action-semantic tasks. Both groups were comparable on remaining linguistic measures. Low-actionality and transitive Vs were the most demanding for patients. EF measures did not discriminate patients from controls but were mostly related to V naming in patients. V deficit was related to patients’ ECAS scores but not to other disease-related variables. Discussion. Impaired action semantics cannot account for N-V dissociation in MND patients, which would rather reflect a magnification of a differential EF-related processing demand for Vs vs. Ns intrinsic to the neurocognitive system. Nonetheless, since N-V dissociation in MND patients is augmented by psycholinguistic variables, it might imply prerolandic involvement in V lexical processing. Furthermore, V deficit has been shown to be predictive towards patients’ neuropsychological outcome. Conclusions. ECT-framed explanations for V deficit in the MND patients are not valid. On the contrary, interplays of linguistic and extra-linguistic explanations should be considered. Deficit in V naming can be found in MND patients and should be considered as a sensitive marker of cognitive impairment in those patients.
Aiello, E., Luzzatti, C., Pain, D., Gallucci, M., Mora, G. (2019). Neurolinguistic investigation of noun-verb dissociation in motor neuron disease. Intervento presentato a: Annual Meeting of Milan Center for Neuroscience, Milan, Italy.
Neurolinguistic investigation of noun-verb dissociation in motor neuron disease
Edoardo Nicolò Aiello
Membro del Collaboration Group
;Claudio LuzzattiMembro del Collaboration Group
;Marcello Gallucci;
2019
Abstract
Object. Selective deficit of verb (V) vs. noun (N) processing has been consistently reported in the motor neuron disease – frontotemporal dementia (MND-FTD) complex. Prerolandic regions atrophy has been traditionally thought to account for N-V dissociation in the MND-FTD complex via selective action semantics impairment (Embodied Cognition Theory, ECT). Nonetheless, explanations pertaining to both sensitivity of those regions to morpho-phonological structure of Vs and executive functioning (EF) contribution have not been endorsed. The aims of this study was to both assess neurocognitive mechanisms underlying N-V dissociation in MND patients and validate its cognitive diagnostic role in this population. Materials. Thirty consecutive MND patients and 29 healthy controls were recruited. Patients’ clinical features (disease duration; site of onset; bulbar signs) and both neuropsychological (Edinburgh Cognitive and Behavioral ALS Screen, ECAS) and functional outcomes were considered. Methods. The two groups were compared on tasks evaluating N and V lexical retrieval, object- and action-semantics, and V lexical-morphosyntactic implementation, while controlling for EF measures. Effects of motor feature degree (actionality) and lexical-morphosyntactic complexity of items on lexical retrieval were assessed via logistic linear mixed models; between-groups comparisons were implemented via overdispersed linear models. Clinical relevance of N-V dissociation was investigated by assessing its association with disease-related variables. Results. Both groups performed worse in V than in N naming. Patients performed worse than controls in V naming and both object- and action-semantic tasks. Both groups were comparable on remaining linguistic measures. Low-actionality and transitive Vs were the most demanding for patients. EF measures did not discriminate patients from controls but were mostly related to V naming in patients. V deficit was related to patients’ ECAS scores but not to other disease-related variables. Discussion. Impaired action semantics cannot account for N-V dissociation in MND patients, which would rather reflect a magnification of a differential EF-related processing demand for Vs vs. Ns intrinsic to the neurocognitive system. Nonetheless, since N-V dissociation in MND patients is augmented by psycholinguistic variables, it might imply prerolandic involvement in V lexical processing. Furthermore, V deficit has been shown to be predictive towards patients’ neuropsychological outcome. Conclusions. ECT-framed explanations for V deficit in the MND patients are not valid. On the contrary, interplays of linguistic and extra-linguistic explanations should be considered. Deficit in V naming can be found in MND patients and should be considered as a sensitive marker of cognitive impairment in those patients.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.