Medial temporal lobe atrophy relates to executive dysfunction in Alzheimer's disease.

BACKGROUND: White matter hyperintensities (WMH) have frequently been associated with lower executive function performance. Little is known, however, about the effects of hippocampal atrophy on executive control in Alzheimer's disease (AD). The present study focused on the association of hippocampal atrophy with executive function in AD patients and examined whether a threshold effect is present, indicating that a certain amount of brain damage must be present before cognitive function becomes impaired. Finally, we examined the combined effect of hippocampal atrophy and WMH on cognitive task performance. METHODS: We retrospectively collected neuropsychological and neuroimaging data of 94 AD patients. These patients completed tasks of general cognitive function, executive function, memory, and processing speed. With magnetic resonance imaging (MRI), hippocampal atrophy was rated as medial temporal lobe atrophy (MTA) and cerebrovascular disease was rated as WMH using validated visual rating scales. RESULTS: Medial temporal lobe atrophy (MTA) was associated with lower executive function, general cognitive function, and episodic memory performance. A threshold effect was present, indicating that severe to very severe, but not moderate, MTA was associated with lower executive function. WMH were significantly associated with a single executive test only, whereas the interaction between WMH and MTA was not significantly related to any of the cognitive tasks. CONCLUSIONS: Our findings suggest that AD neuropathology in itself may be responsible for executive dysfunction. Potential explanations for these findings are discussed, focusing on the role of the hippocampus in executive function tests and reduced frontal-posterior connectivity in this patient sample.

Multifactorial fall prevention for pairs of frail community-dwelling older fallers and their informal caregivers: a dead end for complex interventions in the frailest fallers.

OBJECTIVE: To assess whether a multifactorial fall prevention program was more effective than usual geriatric care in preventing falls and reducing fear of falling in frail community-dwelling older fallers, with and without cognitive impairment, and in alleviating subjective caregiver burden in caregivers. DESIGN, SETTING, AND PARTICIPANTS: A randomized, 2 parallel-group, single-blind, multicenter trial conducted in 36 pairs of frail fallers, who were referred to a geriatric outpatient clinic after at least 1 fall in the past 6 months, and their informal caregivers. INTERVENTION: Groups of 5 pairs of patients and caregivers received 10 twice-weekly, 2-hour sessions with physical and psychological components and a booster session. MEASUREMENTS: The primary outcome was the fall rate during a 6-month follow-up. Additionally, we measured fear of falling and subjective caregiver burden. Data on the secondary outcome measures were collected at baseline, directly after, and at 3 and 6 months after the last session of the intervention. RESULTS: Directly after the intervention and at the long-term evaluation, the rate of falls in the intervention group was higher than in the control group, although these differences were not statistically significant (RR = 7.97, P = .07 and RR = 2.12, P = .25, respectively). Fear of falling was higher in the intervention group, and subjective caregiver burden did not differ between groups. CONCLUSION: Although we meticulously developed this pairwise multifactorial fall prevention program, it was not effective in reducing the fall rate or fear of falling and was not feasible for caregivers, as compared with regular geriatric care. Future research initiatives should be aimed at how to implement the evidence-based principles of geriatric fall prevention for all frail fallers rather than developing more complex interventions for the frailest.

Developing and evaluating complex healthcare interventions in geriatrics: the use of the medical research council framework exemplified on a complex fall prevention intervention.

Geriatrics focuses on a variety of multiorgan problems in a heterogeneous older population. Therefore, most geriatric healthcare interventions are complex interventions. The UK Medical Research Council (MRC) has developed a framework to systematically design, evaluate, and implement complex interventions. This article provides an overview of this framework and illustrates its use in geriatrics by showing how it was used to develop and evaluate a fall prevention intervention. The consecutive phases of the framework are described: Phase I: Development. This phase began with a literature review, which provided the existing evidence and the theoretical understanding of the process of change. This understanding was further developed through focus groups with experts and interviews with patients and caregivers. The intervention was modeled using qualitative testing of the preliminary intervention through focus groups and through the completion of Delphi surveys by independent specialists. Phase II: Feasibility and piloting. In this phase, a pilot study was conducted in a group of patients and caregivers. The feasibility of the intervention and evaluation was also discussed in focus groups of participants and instructors. Phase III: Evaluation. The information from phases I and II shaped the design of a randomized controlled trial to test the effectiveness of the intervention. Phase IV: Dissemination. The purpose of the final phase is to examine the implementation of the intervention into practice. The MRC framework provides an innovative and useful methodology for the development and evaluation of complex geriatric interventions that deserves greater dissemination and implementation.

The effect of cognitive dual tasks on balance during walking in physically fit elderly people.

OBJECTIVE: To evaluate the effect on balance of 3 different cognitive dual tasks performed while walking without and with standardization for gait velocity, and measured with both foot placements and trunk movements. DESIGN: Cross-sectional study. SETTING: Community. PARTICIPANTS: Fifty-nine physically fit elderly people (mean age, 73.5y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Stride length and time variability measured with an electronic walkway, body sway measured with an angular velocity instrument, and gait velocity. RESULTS: Overall, dual tasks resulted in decreased gait velocity (1.46 to 1.23m/s, P<.001), increased stride length (1.4% to 2.6%), and time variability (1.3% to 2.3%) (P<.001), and had no significant effect on body sway. After standardization for gait velocity, the dual tasks were associated with increased body sway (111% to 216% of values during walking without dual task, P<.001) and increased stride length and time variability (41% to 223% increase, P<.001). CONCLUSIONS: In physically fit elderly people, cognitive dual tasks influence balance control during walking directly as well as indirectly through decreased gait velocity. Dual tasks increase stride variability with both mechanisms, but the increase in body sway is only visible after standardization for gait velocity. The decreased gait velocity can be a strategy with which to maintain balance during walking in more difficult circumstances.