Stéphane Adam

Does Retirement Affect Cognitive Functioning

This paper analyses the effect of retirement on cognitive functioning using a longitudinal survey among older Americans, which allows controlling for individual heterogeneity and endogeneity of the retirement decision by using the eligibility age for social security as an instrument. The results highlight a significant negative effect of retirement on cognitive functioning. Our findings suggest that reforms aimed at promoting labour force participation at an older age may not only ensure the sustainability of social security systems but may also create positive health externalities for older individuals.

Memory evaluation with a new cued recall test in patients with mild cognitive impairment and Alzheimer’s disease

Free delayed recall is considered the memory measure with the greatest sensitivity for the early diagnosis of dementia. However, its specificity for dementia could be lower, as deficits other than those of pure memory might account for poor performance in this difficult and effortful task. Cued recall is supposed to allow a better distinction between poor memory due to concurrent factors and impairments related to the neurodegenerative process. The available cued recall tests suffer from a ceiling effect. This is a prospective, longitudinal study aiming to assess the utility of a new memory test based on cued recall that avoids the ceiling effect in the early diagnosis of Alzheimer’s disease (AD). Twenty-five patients with mild cognitive impairment (MCI), 22 probable AD patients (NINCDS-ADRDA) at a mild stage, 22 elderly patients with subjective memory complaints (SMC) and 38 normal age-matched controls took part in the study. The patients underwent a thorough cognitive evaluation and the recommended screening procedure for the diagnosis of dementia. All patients were re-examined 12–18 months later. A newly devised delayed cued recall test using semantic cues (The RI48 Test) was compared with three established memory tests: the Ten Word-List Recall from CERAD, the “Doors” and the “Shapes” Tests from “The Doors and People Test Battery”. Forty-four % of the MCI patients fulfilled criteria for probable AD at follow-up. The RI48 Test classified correctly 88% of the MCI and SMC participants and was the best predictor of the status of MCI and mild AD as well as the outcome of the MCI patients. Poor visual memory was the second best predictor of those MCI patients who evolved to AD. A cued recall test which avoids the ceiling effect is at least as good as the delayed free recall tests in the early detection of AD.

Investigation of implicit memory during isoflurane anesthesia for elective surgery using the process dissociation procedure

Background:This prospective study evaluated memory function during general anesthesia for elective surgery and its relation to depth of hypnotic state. The authors also compared memory function in anesthetized and nonanesthetized subjects. Methods:Words were played for 70 min via headphones to 48 patients (aged 18–70 yr) after induction of general anesthesia for elective surgery. Patients were unpremedicated, and the anesthetic regimen was free. The Bispectral Index (BIS) was recorded throughout the study. Within 36 h after the word presentation, memory was assessed using an auditory word stem completion test with inclusion and exclusion instructions. Memory performance and the contribution of explicit and implicit memory were calculated using the process dissociation procedure. The authors applied the same memory task to a control group of nonanesthetized subjects. Results:Forty-seven patients received isoflurane, and one patient received propofol for anesthesia. The mean (± SD) BIS was 49 ± 9. There was evidence of memory for words presented during light (BIS 61–80) and adequate anesthesia (BIS 41–60) but not during deep anesthesia (BIS 21–40). The process dissociation procedure showed a significant implicit memory contribution but not reliable explicit memory contribution (mean explicit memory scores 0.05 ± 0.14, 0.04 ± 0.09, and 0.05 ± 0.14; mean automatic influence scores 0.14 ± 0.12, 0.17 ± 0.17, and 0.18 ± 0.21 at BIS 21–40, 41–60, and 61–80, respectively). Compared with anesthetized patients, the memory performance of nonanesthetized subjects was better, with a higher contribution by explicit memory and a comparable contribution by implicit memory. Conclusion:During general anesthesia for elective surgery, implicit memory persists even in adequate hypnotic states, to a comparable degree as in nonanesthetized subjects.

The cognitive management of daily life activities in patients with mild to moderate Alzheimer's disease in a day care centre: A case report

The day care centre appears to be a structure especially well suited for the management of mild to moderate Alzheimer patients. It constitutes a place in which performance in everyday life activities can be explored, and optimisation strategies can be installed before they are used at home. Another objective of the day care centre might also be to provide caregivers with support and ease the burden that the daily care of a demented patient represents. Finally, it may also help to alleviate the patients loneliness. In this perspective, we describe the general organisation of the recently-created day care centre at the University Hospital of Liège. We also present the assessment and intervention programme which was conducted in this day care centre in order to reduce the generalised apathy and depressed mood observed in a 70-year-old Alzheimer patient (AM). This programme aimed at restoring a leisure activity (knitting) at home by proposing several adaptations designed to minimise the impact of AMs cognitive deficits on knitting activity. While an aggravation of her memory deficits was observed, the intervention significantly decreased AMs apathy and depressed mood as well as her husbands burden.

Face-name association learning in early Alzheimer's disease: A comparison of learning methods and their underlying mechanisms

This study compared the efficacy of five learning methods in the acquisition of face–name associations in early dementia of Alzheimer type (AD). The contribution of error production and implicit memory to the efficacy of each method was also examined. Fifteen participants with early AD and 15 matched controls were exposed to five learning methods: spaced retrieval, vanishing cues, errorless, and two trial-and-error methods, one with explicit and one with implicit memory task instructions. Under each method, participants had to learn a list of five face–name associations, followed by free recall, cued recall and recognition. Delayed recall was also assessed. For AD, results showed that all methods were efficient but there were no significant differences between them. The number of errors produced during the learning phases varied between the five methods but did not influence learning. There were no significant differences between implicit and explicit memory task instructions on test performances. For the control group, there were no differences between the five methods. Finally, no significant correlations were found between the performance of the AD participants in free recall and their cognitive profile, but generally, the best performers had better remaining episodic memory. Also, case study analyses showed that spaced retrieval was the method for which the greatest number of participants (four) obtained results as good as the controls. This study suggests that the five methods are effective for new learning of face–name associations in AD. It appears that early AD patients can learn, even in the context of error production and explicit memory conditions.

Specificity of inhibitory deficits in normal aging and Alzheimer's disease

Deficits of suppression abilities are frequently observed in normal aging and Alzheimers disease. However, few studies have explored these deficits in the two populations simultaneously using a large battery of tasks. The aim of the present study was to explore if the pattern of performance presented by elderly subjects and AD patients is in agreement with theoretical frameworks [Wilson, S.P., Harnishfeger, K.K., 1998. The development of efficient inhibition: Evidence from directed forgetting tasks. Dev. Rev. 18, 86-123; see also Nigg J.T., 2000. On inhibition/disinhibition in developmental psychopathology: views from cognitive and personality psychology and a working inhibition taxonomy. Psychol. Bull. 126, 220-246], distinguishing between the concepts of inhibition (a voluntary suppression of irrelevant information) and interference (an automatic suppression process occurring prior to conscious awareness). The results obtained demonstrated that (1) there is an alteration of the inhibitory process in normal elderly subjects; (2) inhibitory and interference resolution processes are quantitately less efficient in AD, since these patients present a correct performance only for information which leaves weak traces in memory.

Optimization of encoding specificity for the diagnosis of early AD : the RI-48 task.

The aim of this study was to evaluate the discriminant validity of the RI-48 test, a shorter French version of the Category Cued Recall portion of the Double Memory Test developed initially by Buschke and colleagues (1997), in the diagnosis of mild and very mild Alzheimer disease (AD). The distinctive feature of the RI-48 task is that encoding specificity was increased by adding an immediate cued recall stage at the encoding phase. The results show that the RI-48 task seems to be well adapted to the clinical context and to have good psychometric properties, in particular a lack of a ceiling effect. Moreover, this task appears to be especially well suited for the diagnosis of both mild and very mild AD (sensitivity of 93% and 83.8%). From a more theoretical point of view, this study confirms the importance of optimizing the encoding specificity for the diagnosis of very mild AD, since the more encoding specificity is accentuated, the more discriminating power is increased for the diagnosis of very mild AD.

Occupational activity and cognitive reserve: implications in terms of prevention of cognitive aging and Alzheimer's disease.

This paper investigates the relationship between the concept of activity (including both professional and nonprofessional) and cognitive functioning among older European individuals. In this research, we used data collected during the first wave of SHARE (Survey on Health, Ageing and Retirement in Europe), and a measurement approach known as stochastic frontier analysis, derived from the economic literature. SHARE includes a large population (n > 25,000) geographically distributed across Europe, and analyzes several dimensions simultaneously, including physical and mental health activity. The main advantages of stochastic frontier analysis are that it allows estimation of parametric function relating cognitive scores and driving factors at the boundary and disentangles frontier noise and distance to frontier components, as well as testing the effect of potential factors on these distances simultaneously. The analysis reveals that all activities are positively related to cognitive functioning in elderly people. Our results are discussed in terms of prevention of cognitive aging and Alzheimer’s disease, and regarding the potential impact that some retirement programs might have on cognitive functioning in individuals across Europe.

Anxiety and depression, attention, and executive functions in hypothyroidism.

BACKGROUND Divergences in cognitive disturbances in hypothyroidism reported in the literature are a result of a methodological bias. METHODS By using a precise methodology, we examined attention and executive functions in hypothyroidism, verified the presence of anxiety and depressive symptoms in hypothyroidism, and examined the possible link between these symptoms and the cognitive disturbances (searching for attentional bias for words with a negative emotional valence). We administered a battery of cognitive tests to 23 participants who had undergone thyroidectomy for thyroid carcinoma: for the first time in an euthyroid state, then 3 weeks later (still in the euthyroid state) to assess the test/retest effect, and finally 4 weeks later in an hypothyroid state. We compared their performance with that of a group of 26 control participants who were also administered the same cognitive tests, also 3 times. RESULTS In hypothyroidism, the thyroid participants were more anxious and depressed than the controls and presented attentional and executive disturbances that reflected general slowing and difficulties in using their capacities of inhibition. However, they did not exhibit an attentional bias for words with a negative emotional valence. CONCLUSIONS Contrary to what was expected, symptoms of anxiety and not symptoms of depression interfered with the cognitive performance of participants in hypothyroidism.

Cerebral metabolic correlates of four dementia scales in Alzheimer's disease

Abstract Different scales can be used to evaluate dementia severity in Alzheimer’s disease (AD). They do assess different cognitive or functional abilities, but their global scores are frequently in mutual correlation. Functional imaging provides an objective method for the staging of dementia severity. Positron emission tomography was used to assess the relationship between brain metabolism and four dementia scales that reflect a patient’s global cognitive abilities (mini mental state), caregiver’s evaluation of cognitive impairment (newly designed scale), daily living functioning (instrumental activities of daily living) and global dementia (clinical dementia rating). We wondered whether different clinical dementia scales would be related to severity of metabolic impairment in the same brain regions, and might reflect impairment of common cognitive processes. 225 patients with probable AD were recruited in a prospective multicentre European study. All clinical scales were related to brain metabolism in associative temporal, parietal or frontal areas. A factorial analysis demonstrated that all scales could be classified in a single factor. That factor was highly correlated to decrease of cerebral activity in bilateral parietal and temporal cortices, precuneus, and left middle frontal gyrus. This finding suggests that global scores for all scales provided similar information on the neural substrate of dementia severity. Capitalizing on the neuroimaging literature, dementia severity reflected by reduced metabolism in posterior and frontal associative areas in AD might be related to a decrease of controlled processes.