Efficacy of Cognitive Rehabilitation Versus Usual Treatment at Home in Patients With Early Stages of Alzheimer Disease.

INTRODUCTION: Assessing the benefit of cognitive rehabilitation (CR) remains difficult. METHOD: An observational study was conducted in 33 patients with early-stage Alzheimer disease and their caregiver included in a clinical CR program at home, compared to 17 patients who received usual treatment. Evaluation of patient's dependence and objective and subjective caregiver's burden was performed by the caregiver with a research tool focusing on impairment in daily activities related to cognitive deficits. RESULTS: Repeated measures analysis of variance showed a time by group interaction (P < .05), with decreased patient's dependence for adapted activities at 1 year in the CR group. Lawton scale for daily activities showed also a time by group interaction (P < .05), with increased dependence at 1 year in the control group. There was a significant decrease in Mini-Mental State Examination scores in both groups at 1-year follow-up (P < .05). Concerning caregiver's subjective burden, there was a trend for the time by group interaction (P = .07), and post hoc Tukey test showed that subjective burden was decreased in the CR group (P < .05). This was confirmed by nonparametric Mann-Whitney analysis on differences between follow-up and baseline evaluation (P < .05). CONCLUSION: This observational study in a clinical setting is in line with the benefit of CR reported in recent randomized controlled trials. The benefit obtained for adapted daily activities remained after 1 year, even if global cognition declined. Moreover, caregiver's subjective burden related to all relevant daily activities evaluated within the CR program was decreased after 1 year in our clinical setting.

Alzheimer's disease patients activate attention networks in a short-term memory task.

Network functioning during cognitive tasks is of major interest in Alzheimer's disease (AD). Cognitive functioning in AD includes variable performance in short-term memory (STM). In most studies, the verbal STM functioning in AD patients has been interpreted within the phonological loop subsystem of Baddeley's working memory model. An alternative account considers that domain-general attentional processes explain the involvement of frontoparietal networks in verbal STM beside the functioning of modality-specific subsystems. In this study, we assessed the functional integrity of the dorsal attention network (involved in task-related attention) and the ventral attention network (involved in stimulus-driven attention) by varying attentional control demands in a STM task. Thirty-five AD patients and twenty controls in the seventies performed an fMRI STM task. Variation in load (five versus two items) allowed the dorsal (DAN) and ventral attention networks (VAN) to be studied. ANOVA revealed that performance decreased with increased load in both groups. AD patients performed slightly worse than controls, but accuracy remained above 70% in all patients. Statistical analysis of fMRI brain images revealed DAN activation for high load in both groups. There was no between-group difference or common activation for low compared to high load conditions. Psychophysiological interaction showed a negative relationship between the DAN and the VAN for high versus low load conditions in patients. In conclusion, the DAN remained activated and connected to the VAN in mild AD patients who succeeded in performing an fMRI verbal STM task. DAN was necessary for the task, but not sufficient to reach normal performance. Slightly lower performance in early AD patients compared to controls might be related to maintained bottom-up attention to distractors, to decrease in executive functions, to impaired phonological processing or to reduced capacity in serial order processing.

Effects of aging on task- and stimulus-related cerebral attention networks.

Interactions between a dorsal attention network (DAN) and a ventral attention cerebral network (VAN) have been reported in young participants during attention or short-term memory (STM) tasks. Because it remains an underinvestigated question, age effects on DAN and VAN activity and their functional balance were explored during performance of an STM task. Older and younger groups showed similar behavioral patterns of results. At the cerebral level, DAN activation increased as a function of increasing STM load in both groups, suggesting preserved activity in DAN during healthy aging. Age-related over-recruitment in regions of the DAN in the higher task load raised the question of compensation attempt versus less efficient use of neural resources in older adults. Lesser decrease of VAN activation with increasing load and decreased stimulus-driven activation in the VAN, especially in the higher load, in older participants suggested age-related reduced response in the VAN. However, functional connectivity measures showed that VAN was still functionally connected to the DAN in older participants.

Recognition of personally familiar faces and functional connectivity in Alzheimer's disease.

Studies have reported that patients in the severe stages of Alzheimer's disease (AD) experience difficulties recognizing their own faces in recent photographs. Two case reports of late-stage AD showed that this loss of self-face recognition was temporally graded: photographs from the remote past were recognized more easily than more recent photographs. Little is known about the neural correlates of own face recognition abilities in AD patients, while neuroimaging studies in healthy adults have related these abilities to a bilateral fronto-parieto-occipital network. In this study, two behavioral experiments (experiments 1 and 2) and one functional magnetic resonance imaging (fMRI) experiment (second part of experiment 2) were conducted to compare mild AD patients (experiment 1) and moderate AD patients (experiment 2) with healthy older participants in a recognition task involving self and familiar faces from different decades of the participants' life. In moderate AD patients, variable performance allowed us to examine correlations between scores and resting-state fMRI in order to link behavioral data to cerebral activity. At the behavioral level, the results revealed that, in mild AD, self and familiar face recognition was preserved. Moreover, mild AD patients and healthy older participants showed an inverse temporal gradient, with faster recognition of self and familiar recent photographs than self and familiar remote photographs. However, in moderate AD, both self and familiar face recognition were affected. fMRI results showed that the higher the connectivity between the dorsomedial prefrontal cortex (dMPFC) and the right superior frontal gyrus (rSFG), the lower the self and familiar face recognition scores in moderate AD patients. Given that previous studies have related the superior frontal region to control processes rather than face recognition processes, these results might reflect less segregation and more interference between brain networks in AD. In other words, impaired face recognition in AD may be related to functional dedifferentiation of specific brain regions.