Beyond the motor account of amyotrophic lateral sclerosis: Verbal humour and its relationship with the cognitive and pragmatic profile

Background: Amyotrophic Lateral Sclerosis (ALS) was traditionally described as a disease restricted to the motor system. However, recent findings suggested that it also affects cognition, especially executive functions, social cognition, language and pragmatics. A relevant issue in current research is thus the description of the cognitive phenotype of ALS and the identification of the most vulnerable aspects. Aims: The focus was on a communicative phenomenon placed at the crossroads of pragmatic and other cognitive domains, namely humour, which till now has been poorly explored in ALS. The first aim was to investigate whether ALS is associated with impairments in understanding and appreciating jokes. The second aim was to explore the predictors of humour comprehension and appreciation in patients, to confirm the involvement of pragmatic skills and to explore the role of other cognitive and clinical aspects. Methods & Procedures: A total of 30 non-demented patients with ALS and 27 controls were assessed with a task of verbal humour comprehension and appreciation, including two types of jokes: phonological and mental. We also administered a battery of pragmatic and other language tasks, and cognitive and socio-cognitive tasks. Mixed-effects models were used to test differences in the humour task between the two groups. Multiple regressions determined the best predictors of humour comprehension and appreciation in patients. Outcomes & Results: Patients obtained lower comprehension accuracy scores than controls in the humour task, independently of the type of joke. Conversely, patients and controls did not differ in joke appreciation and both rated mental jokes as funnier than the phonological ones. Patients’ comprehension accuracy was predicted by pragmatic skills and ALS severity, whereas appreciation was predicted by several clinical variables and, to a smaller extent, by language skills. Conclusions & Implications: The findings suggest that humour is a very vulnerable aspect in ALS, and that impairment in humour comprehension might be part of the larger cognitive impairment, being linked to pragmatic impairment. Clinical variables were also important, especially in relation to humour appreciation. More generally, these data speak in favour of pragmatics as a relevant aspect to sketch the cognitive phenotype of ALS. On the practical level, these findings point to the need of supporting communication at large, not only motor-related aspects such as dysarthria but also social–pragmatic aspects such as understanding jokes, to increase well-being in ALS. What this paper adds What is already known on this subject The literature of the last decades has shown that ALS comes with impairment in several cognitive domains, affecting especially executive functions as well as language. There is also initial evidence that the pragmatics of communication and humour comprehension are impaired, although non-serious talk has been documented in conversational interaction among people with ALS. What this paper adds to existing knowledge This study offers compelling evidence of an impairment in the comprehension of jokes in ALS, whereas the appreciation of joke funniness seems to be spared. The study also highlights the interplay of cognitive factors (especially pragmatics) and clinical factors (related to disease severity) in predicting the patients’ performance in the humour task. What are the potential or actual clinical implications of this work? The study's findings call for the need of increased awareness among scholars as well as practitioners and caregivers of the profile of humour comprehension and appreciation in ALS. On a practical level, we highlight the need of assessing humour comprehension and adapting the communicative style accordingly. Second, we recommend that intervention programmes targeting communication in ALS go beyond speech-related difficulties and include pragmatic aspects such as humour. Considering the important communicative and social function of humour, as well as its use as a coping strategy, humour interventions are key to improve the quality of life of individuals with ALS.