Observing conversational laughter in frontotemporal dementia

Abstract

Background We performed an observational study of laughter during seminaturalistic conversations between patients with dementia and familial caregivers. Patients were diagnosed with (1) behavioural variant fronto-temporal dementia (bvFTD), (2) right temporal variant frontotemporal dementia (rtFTD), (3) semantic variant of primary progressive aphasia (svPPA), (4) non-fluent variant primary progressive aphasia (nfvPPA) or (5) early onset Alzheimer’s disease (eoAD). We hypothesised that those with bvFTD would laugh less in response to their own speech than other dementia groups or controls, while those with rtFTD would laugh less regardless of who was speaking. Methods Patients with bvFTD (n=39), svPPA (n=19), rtFTD (n=14), nfvPPA (n=16), eoAD (n=17) and healthy controls (n=156) were recorded (video and audio) while discussing a problem in their relationship with a healthy control companion. Using the audio track only, laughs were identified by trained coders and then further classed by an automated algorithm as occurring during or shortly after the participant’s own vocalisation (‘self’ context) or during or shortly after the partner’s vocalisation (‘partner’ context). Results Individuals with bvFTD, eoAD or rtFTD laughed less across both contexts of self and partner than the other groups. Those with bvFTD laughed less relative to their own speech compared with healthy controls. Those with nfvPPA laughed more in the partner context compared with healthy controls. Conclusions Laughter in response to one’s own vocalisations or those of a conversational partner may be a clinically useful measure in dementia diagnosis.

The spectrum of involuntary vocalizations in humans: A video atlas

“…Laughter and crying behaviors that occur detached from emotional content were reported in patients with TS as part of tic behaviors 160 and other neurodevelopmental disorders (eg, Angelman syndrome, 161 partial trisomy 16p, 15 and Rett-like syndromes 162 ). However, pathological laughter and crying is most commonly associated with neurodegenerative disorders, such as ALS, 163 FTD, 164 Alzheimer's disease, 165 primary progressive aphasia, 166 multiple system atrophy cerebellar type, 167 CJD, 168 spinocerebellar ataxia (SCA) 17, 169 and HD. Focal brain lesions in cerebrovascular disease, [170][171][172][173][174][175][176][177] traumatic brain injury, [178][179][180] autoimmune-mediated lesions in disseminated encephalomyelitis [181][182][183] or drug-induced behavior 184 are additional etiologies.…”

Neuroanatomy of Shared Conversational Laughter in Neurodegenerative Disease

“…This low level of laughter overall has been previously described using the same task. As in that publication, nfvPPA stands out from other groups in conversational laughter production, which may represent a paralinguistic method of social connection to compensate for an often-frustrating apraxia of speech ( 21 ). Further studies in other samples would be necessary to confirm and help explain this behavior.…”

“…Similarly, altered social dynamics are common among those with neurodegenerative diseases ( 20 ). Based on these altered patterns of social interaction, we previously identified different patterns of conversational laughter among some patients with neurodegeneration ( 21 ). The purpose of our current study was to investigate the neural correlates of shared conversational laughter during naturally occurring conversation among patients with one of a variety of neurodegenerative illnesses ( N = 75).…”

Laughter as a paradigm of socio-emotional signal processing in dementia

“…Indeed, neurodegenerative diseases have been linked to abnormalities of laughter behaviour in daily life. In the context of punctuating conversation, patients with bvFTD (and also AD) laugh less whereas patients with nfvPPA may laugh more than their healthy caregivers (49); while patients with bvFTD and svPPA often laugh inappropriately, for example in response to others' misfortune (50). However, laughter processing has not been studied systematically in neurodegenerative disease.…”

“…Neuroanatomical associations of laughter identi cation in the patient cohort were assessed using voxelbased morphometry. Based on available evidence (20,23,(25)(26)(27)(49)(50)(51), we hypothesised that impairments of laughter processing would be widespread across FTD and AD but would show dissociated patterns of de cits in different syndromes. We predicted more severe de cits in FTD syndromes than in AD, with a more elementary de cit of perceptual analysis in nfvPPA and more severe social and emotional processing de cits in svPPA and bvFTD.…”