Clinical and functional impact of cognitive fluctuations in dementia

Cognitive fluctuations (CFs) are defined as spontaneous alterations in cognition, attention, and arousal, and are highly prevalent and disabling among people with dementia. CFs occur with a frequency of 80-90% in dementia with Lewy bodies (DLB), 40% in vascular dementia (VaD), and 20% in Alzheimer’s disease (AD). While CFs have been recognized as an important component of dementia, the majority of studies examining them have lacked objective methods of assessing their presence and severity, making it difficult to determine the degree of interference with other clinical features that can be attributable to fluctuations. The present study examined the nature and frequency of CFs in 55 individuals with dementia living in a long-term care facility. Participants underwent neuropsychological assessment to profile their current cognitive functioning. The Dementia Cognitive Fluctuation Scale (DCFS) was used to characterize CFs in this sample. Patients also completed brief cognitive measures on three separate occasions during a one-week period to obtain objective evidence of variability in cognitive performance. This study also assessed the association between CFs and informant based measures of patients’ quality of life, activities of daily living, and formal caregiver burden. Longitudinal cognitive data was analyzed retrospectively to determine patients’ rate of cognitive decline over the past six months. Consistent with the limited research already completed in this area, this study found that increasing severity of CFs predicts lower cognitive performance and reduced ability to complete activities of daily living. Also, this is the first study to demonstrate that CFs predict patients’ overall quality of life and the degree of caregiver burden in primary nursing staff. Results of the current study suggest that CFs exert a broad range of influence over patients’ functional abilities and well being. Identifying which patients experience CFs could play an important role in developing individualized treatment plans best suited for patients specific care needs.