"Sundown syndrome," which is the development or worsening of Neuropsychiatric Syndrome (NPS) in the late afternoon or early evening, is a disorder that accurately matches the pertinent complexity of the neuropsychiatric manifestations of dementia. It represents a relevant and challenging manifestation of dementia, occurring in a large proportion of affected individuals and being associated with a significant social and economic burden. A major source of stress for patients and families, NPS are key characteristics of dementias that are present in the vast majority of cases. It widely includes behavioural and psychiatric disturbances such as anxiety, agitation, aggression, pacing, wandering, resistance, screaming, yelling, visual and auditory hallucination and exacerbation of cognitive symptoms and confusion.
20% of Alzheimer's patients as well as those with non-AD dementias such vascular dementia, frontotemporal dementia, lewy body dementia, etc. have sundowning diagnosed. In nursing homes, it has frequently been labelled as "endemic" and associated with faster progression of cognitive worsening in AD. Behavioural disruptions in the late afternoon or in the evening may pose a specific challenge to caregivers. A “stressed caring” can trigger an exacerbation of NPS causing a potential dangerous loop.
Degeneration of the cholinergic system may contribute to the disruption of circadian rhythms and emergence of behavioural disturbances. In AD, the aetiology of sundowning has been linked to dysregulations of the hypothalamic-pituitary-adrenal axis. Moreover, AD patients with sundowning have shown significantly higher cortisol than those without sundowning. In addition, environmental factors such as a lessened light exposure during the day, the reduced availability of caregivers during evening, afternoon fatigue etc have been all associated with an overall worsening of NPS and the emergence of a sundowning. Parallelly, pharmacological factors such as antidepressants, antipsychotics, dopaminergic therapies etc and medical conditions such as pain, visual and/or hearing impairment, mood disorders etc may induce evening agitation.
To provide targeted interventions on time, special attention should be given to identifying potentially curable underlying problems. Sundowning can be clinically approached through direct observation of patients, general physical examination such as pain, sensory deprivation, an environmental evaluation such as lighting, noise levels, changes in daily routine and iatrogenic triggers etc. However, to date, there are no dedicated and valid tools to screen sundowning.
The identification and execution of targeted and individualized therapies may be made more difficult by the temporal fluctuations in symptom severity and the variability of potential triggers. However, individually tailored non-pharmacological approaches (such as light therapy, minimizing unnecessary noises, avoiding excessive sensory stimulation during the evening etc) are considered as first-line treatment, limiting pharmacotherapies to non-responsive cases. Most of the available pharmacological interventions have been focused on the clinical efficacy of melatonin supplementation. However, there are limited informations available in the medical literature.
Reference:
Canevelli, Marco; Valletta, Martina; Trebbastoni, Alessandro; Sarli, Giuseppe; D’Antonio, Fabrizia; Tariciotti, Leonardo; de Lena, Carlo; Bruno, Giuseppe (2016). Sundowning in Dementia: Clinical Relevance, Pathophysiological Determinants, and Therapeutic Approaches. Frontiers in Medicine, 3(), –. doi:10.3389/fmed.2016.00073
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