Inhibitory deterioration may contribute to hallucinations in Alzheimer's disease

Haj, Mohamad El; Larøi, Frank; Gély‐Nargeot, Marie‐Christine; Raffard, Stéphane

doi:10.1080/13546805.2015.1023392

Cited by 28 publications

(26 citation statements)

References 58 publications

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“…Hallucinations were mediated by inhibitory decline as assessed with the Stroop task in 31 patients with AD [58]. According to this study, hallucinations in AD patients may be related to difficulties in suppressing intrusive thoughts or memories.…”

Section: Cognitive and Affective Accounts For Hallucinations In Admentioning

confidence: 97%

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Clinical and neurocognitive aspects of hallucinations in Alzheimer’s disease

Haj

Roche

Jardri

et al. 2017

Neuroscience & Biobehavioral Reviews

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Due to their prevalence, hallucinations are considered as one of the most frequent psychotic symptom in Alzheimer’s disease (AD). These psychotic manifestations reduce patients’ well-being, increase the burden of caregivers, contribute to early institutionalization, and are found to be related with the course of cognitive decline in AD. Considering their consequences, we provide a comprehensive account of the current state of knowledge about the prevalence and characteristics of hallucinations in AD. We provide a comprehensive and testable theoretical model about hallucinations in AD: the ALZHA (ALZheimer and HAllucinations) model. In this model, neurological, genetic, cognitive, affective, and iatrogenic factors associated with hallucinations in AD are highlighted. According to this model, hallucinations in AD first involve trait markers (i.e., cognitive deficits, neurological deficits, genetic predisposition and/or sensory deficits) to which state markers that may specifically trigger these experiences are added (e.g., psychological distress and/or iatrogenic factors). Finally, we provide recommendations for assessment and management of these psychotic manifestations in AD, with the aim to both serve patients, caregivers, and health professionals.

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Section: Cognitive and Affective Accounts For Hallucinations In Admentioning

confidence: 97%

“…Independently of their relationship with loneliness and social isolation, hallucinations in AD were also found to be associated with depression [58]. Such a relationship mirrors the frequent occurrence of depressive disorders in individuals suffering from hallucinations [72].…”

Section: Cognitive and Affective Accounts For Hallucinations In Admentioning

confidence: 99%

Clinical and neurocognitive aspects of hallucinations in Alzheimer’s disease

Haj

Roche

Jardri

et al. 2017

Neuroscience & Biobehavioral Reviews

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“…However, again, only a few studies on cognitive functioning and hallucinations including healthy older adults are available and these studies are substantially limited by the fact that their samples of older adults are relatively small and/or the older adults were not their target population. That is, either some older adults were included in the general healthy sample (e.g., Stirling et al, 2007) or they served as controls for studies on hallucinations in Alzheimer's patients (El Haj et al, 2015, 2016). …”

Section: Factors Associated With Hallucinations In Older Adultsmentioning

confidence: 99%

“…These tasks included measures of general cognitive functioning, episodic memory, working memory (forward and backward span), verbal fluency as well as a measure of inhibition (a Stroop task; El Haj et al, 2015) or a measure of directed forgetting (El Haj et al, 2016) and a measure of auditory and visual hallucinations (i.e., 6 items from the Launay Slade Hallucinations Scale-Revised, LSHS-R; Launay and Slade, 1981). Overall, healthy older controls reported less hallucinations and had better performance on the cognitive tests than Alzheimer's disease patients.…”

Section: Factors Associated With Hallucinations In Older Adultsmentioning

confidence: 99%

“…Since compensatory processes have been well-studied in the context of normal ageing (e.g., Reuter-Lorenz and Park, 2014; Peelle and Wingfield, 2016), hallucinatory experiences in healthy older adults may provide a particularly valuable window on the underlying mechanisms involved. Despite this, later-onset hallucinations have mostly been examined in the context of Lewy Body disorders and dementia (Collerton et al, 2012; El Haj et al, 2015). In contrast, the diversity and significance of hallucinations in healthy older adults have received much less attention (Tien, 1991).…”

Section: Introductionmentioning

confidence: 99%

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Hallucinations in Healthy Older Adults: An Overview of the Literature and Perspectives for Future Research

2017

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KEY POINTS ➢ Studies suggest a substantial minority of healthy older adults have hallucinatory experiences, in line with existing evidence on hallucinations in other age groups, though it is still unclear if hallucination prevalence increases or declines with age in older cohorts.➢ Stigma attached to both hallucinations and ageing leads to considerable under-reporting of these experiences in healthy older adults and may negatively bias how professionals, family members, and the public respond.➢ Why and when hallucinations in healthy older adults remit, persist, or progress to other clinical disorders remains poorly understood.➢ Current evidence points to a range of factors associated with hallucinations in older adults including decline in sensory or cognitive functioning, poor sleep, and psychosocial stressors (e.g., social isolation, loneliness, and bereavement), highlighting the need for accurate assessment and tailored interventions.Hallucinations, though common in youth and younger adults, are not the preserve of these age groups. Accumulating evidence shows that hallucinatory experiences are also present at surprisingly high rates in healthy older adults in the general community. Furthermore, stigma and misunderstanding of hallucinations, together with ageism, may lead to under-reporting of these experiences by older adults, and misdiagnosis or mismanagement by health and mental health practitioners. Consequently, improved public and professional knowledge is needed about the nature and significance of hallucinations with advancing age. The purpose of this review is to provide a comprehensive overview, and critical analysis, of research on the prevalence, psychosocial, and neurobiological factors associated with hallucinations in people aged 60 years and over. To the best of our knowledge, this is the first review of its kind in the literature. The evidence supports a dynamic conceptualization of hallucinations, in which the emergence of hallucinations is viewed as a balance between the sensory, cognitive, or social impairments accompanying advancing age and the degree to which compensatory processes elicited by these impairments are successful. We briefly summarize the implications of the literature for aged care services and interventions, and stress that far more studies are needed in this important field of research.

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Memory suppression in Alzheimer’s disease

Haj

2015

Neurol Sci

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An important challenge for memory is the competition between appropriate and inappropriate information during retrieval. This competition is normally reduced thanks to controlled inhibitory processes that suppress irrelevant memories. In Alzheimer's disease (AD), compromise of suppression ability may result in strong competition between relevant and irrelevant memories during retrieval. The present review highlights this issue by examining studies using the directed forgetting method in AD. This method in which participants are typically instructed to forget no longer relevant information is argued to reflect suppression in memory. Studies using the directed forgetting method suggest that AD participants experience difficulties when they are asked to suppress no longer relevant information in working, autobiographical, source and destination memory. Difficulties in suppressing irrelevant information, as may be observed in AD, may hamper memory retrieval by activating irrelevant memories at the expense of relevant ones.

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Inhibitory deterioration may contribute to hallucinations in Alzheimer's disease

Abstract: Hallucinations in individuals with AD seem to be related to difficulties suppressing irrelevant thoughts, resulting in these irrelevant thoughts becoming confused with ongoing reality.

Cited by 28 publications

References 58 publications

Clinical and neurocognitive aspects of hallucinations in Alzheimer’s disease

Clinical and neurocognitive aspects of hallucinations in Alzheimer’s disease

Hallucinations in Healthy Older Adults: An Overview of the Literature and Perspectives for Future Research

Memory suppression in Alzheimer’s disease

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