Neuropsychiatric Disturbances in Mild Cognitive Impairment (MCI): A Systematic Review of Population-Based Studies

Abstract

Mild cognitive impairment (MCI) is a nosological entity associated with a higher risk of developing dementia. Previous evidence indicates that behavioral and psychological symptoms of dementia (BPSDs) frequently occur in individuals of MCI. These neuropsychiatric manifestations may predict conversion to dementia. However, no updated systematic review has been conducted aiming to investigate the prevalence of BPSDs in MCI in general population samples. We conducted a systematic review to summarize research results regarding the prevalence of any or specific BPSDs in MCI subjects out of the clinical setting, compared to subjects who are either cognitively intact and/or demented. The PubMed/MEDLINE, EMBASE, and PsycInfo databases were searched from January 1st, 1990 to January 3rd, 2015 for general population studies in which the prevalence of BPSDs in individuals with MCI was estimated. Twenty-one studies met inclusion criteria. Studies varied in overall methodological quality as evaluated with a modified version of the New Castle-Ottawa Scale for cross-sectional studies. Depression (median prevalence: 29.8%; range: 6.8-63.3%), sleep disturbances (median prevalence: 18.3%; range: 7.9-49.0%), and apathy (median prevalence: 15.2%; range: 2.3-18.5%) were the more frequent BPSDs across studies. The prevalence range for any BPSD was 12.8-66.0%. No consistent pattern for differences in the prevalence of BPSDs according to MCI subtype emerged. Studies considered different diagnostic criteria for MCI and used different instruments to assess BPSDs in this population. In conclusion, BPSDs are prevalent among communitydwelling individuals with MCI. However, consistent socio-demographic and clinical correlates for BPSDs in this population remains to be established.

Subjective-Objective Sleep Discrepancy in Older Adults With MCI and Subsyndromal Depression

“…Indeed, 7% to 49% of older adults with mild cognitive impairment (MCI) report sleep disturbances. 5 Moreover, poor sleep quality in older adults is associated with increased risk of developing cognitive impairment and dementia. 6–8 Implementing effective behavioral (eg, brief behavioral treatment for insomnia and cognitive behavioral therapy for insomnia) and pharmacotherapy (eg, benzodiazepine receptor modulators, sedating antidepressants, melatonin receptor agonists, and orexin receptor inhibitors) treatments may improve sleep quality, which in turn may serve to decrease the progression of decline to dementia.…”

“…16 There is also a well-established relationship among cognitive impairment, sleep complaints, and depressive symptoms which may further complicate clinical assessment. 5,18–21 Since depression has been linked to a negative cognitive bias, its presence may impair self-assessment of symptomatology. 22,23 Therefore, it is unclear to what degree a depressed patient’s self-reported poor sleep quality is reflective of a negative cognitive bias associated with depression versus actual sleep disturbance.…”

Confabulations in Cases of Dementia: Atypical Early Sign of Alzheimer’s Disease or Misleading Feature in Dementia Diagnosis?

“…Nevertheless, biomarkers assessment supported a diagnosis of AD ( McKhann et al, 2011 ), and a diagnosis of frontal variant of AD was eventually made. Noteworthy for the differential diagnosis between AD and FTD is that behavioral alterations appear normally later in AD patients in comparison to memory impairment and social behavior is generally appropriate ( Kohler et al, 2016 ). Moreover, patients with FTD show lower awareness of their deficits in comparison to AD patients ( DeLozier and Davalos, 2016 ) and tend to confabulate more ( Nedjam et al, 2004 ).…”

Depressive disorders in the elderly and dementia: An update

“…In the past two decades, several populational studies have shown that depressive disorders are risk factor for cognitive decline and dementia, especially AD. 22,23 A recent metanalysis including longitudinal studies with 49,612 subjects further promoted the association between depressive disorders and dementia with 2.53 fold-increased risk for vascular dementia and 1.85 foldincreased risk for AD. 24 It is worth mentioning that most studies in this meta-analysis did not clearly differentiate between EoD and LoD.…”