Measuring the impact of cognitive and psychosocial interventions in persons with mild cognitive impairment with a randomized single-blind controlled trial: rationale and design of the MEMO+ study.

BACKGROUND: Several studies have suggested that cognitive training is a potentially effective way to improve cognition and postpone cognitive decline in older adults with mild cognitive impairment (MCI). The MEMO+ study is a randomized, controlled, single-blind trial designed to test the efficacy, specificity, and long-term effect of a cognitive training intervention and a psychosocial intervention in persons with MCI. METHODS: One hundred and sixty-two participants with MCI will be recruited. They will be randomized into three groups: cognitive training, psychosocial intervention, and no-contact. Each intervention will last for eight weeks (one session per week) and a booster training session will be provided three months after the end of the intervention. Various proximal and distal outcomes will be measured at pre-intervention as well as at one week, three months, and six months post-training. Proximal outcomes include memory and psychological health measures. Distal outcomes focus on self-rated functioning in complex daily activities and strategies used in daily life to enhance function. Socio-demographic factors (age, gender, and education), general cognition, personality traits, engagement in activities, and self-efficacy will be used as moderators. Enrolment began in April 2012 and will be completed by December 2014. CONCLUSIONS: This study is likely to have a significant impact on the well-being of persons with MCI by contributing to the development of adapted and scientifically supported cognitive and psychosocial interventions.

Predicting decline in mild cognitive impairment: a prospective cognitive study.

OBJECTIVE: The primary aim of this study was to identify cognitive tests that differentiate between persons with mild cognitive impairment (MCI) who later develop cognitive decline and those who remain stable. METHOD: This study used a prospective longitudinal design. One hundred twenty-two older adults with single-domain or multiple-domain amnestic MCI were recruited from memory clinics. They completed tests to measure baseline episodic memory, working memory, executive functions, perception, and language. They were then followed annually to determine with criteria independent from those tests whether they had remained stable or had developed dementia or significant cognitive decline. This was used as the reference standard to measure diagnostic test accuracy value. RESULTS: ANOVAs indicated that participants with progressive MCI showed more impaired performance than those with stable MCI at baseline on episodic memory (word and story recall), the Brown-Peterson working memory test, object naming, object decision, and position of gap test. Logistic regression derived a significant model with 87.8% overall predictive value. The model included delayed text memory, free recall, naming, orientation match, object decision, and alpha span. Its sensitivity was 86.2% and its specificity was 88.9%. Positive predictive value was 83.3%, and negative predictive value was particularly high at 90.9%. CONCLUSIONS: Identifying individuals with MCI who will progress to dementia or more severe cognitive impairment is a challenge. This study shows that cognitive measures provide valuable information regarding the predictive diagnosis of persons with MCI. Predictive accuracy of a cognitive battery might be optimized by selecting both memory and nonmemory measures.

Executive function deficits in persons with mild cognitive impairment: a study with a Tower of London task.

This study assessed executive functions in persons with mild cognitive impairment (MCI) using the Tower of London (TOL). A second objective was to study the impact of three types of problem selected according to the presence or absence of a "trigger." A trigger (T) is an incitation to the participant, at the first move, to move a ball to its final position according to the model. A positive trigger (T+) is helpful, while a negative trigger (T-) creates an obstruction. Some problems have no trigger (N). This study includes 81 participants with MCI. After follow-up, one year later, two subgroups were distinguished: (a) 51 (63%) participants did not convert or decline (stable MCI); (b) 30 (37%) participants showed significant decline or progressed to dementia (decliner MCI). Persons with MCI were compared to an older adult group matched with respect to sex, age, and education. For the successes, there was a significant group difference between the three types of problem. The post hoc analysis showed that T+ took significantly less time than N or T-. There were significantly more successes for T+ than N, and these two types of problem had more success than T-. For "total number of moves," there was no significant difference between the groups. In post hoc analysis, T- involved more moves than N or T+. In qualitative analysis, T- MCI decliners produced significantly more rule breakings than the stable MCI and controls. A dysfunction in self-monitoring is a characteristic feature of persons with MCI.

Impact of novelty and type of material on recognition in healthy older adults and persons with mild cognitive impairment.

The goal of this study was to assess the effect of novelty on correct recognition (hit minus false alarms) and on recollection and familiarity processes in normal aging and amnestic mild cognitive impairment (MCI). Recognition tasks compared well-known and novel stimuli in the verbal domain (words vs. pseudowords) and in the musical domain (well-known vs. novel melodies). Results indicated that novel materials associated with lower correct recognition and lower recollection, an effect that can be related to its lower amenability to elaborative encoding in comparison with well-known items. Results also indicated that normal aging impairs recognition of well-known items, whereas MCI impairs recognition of novel items only. Healthy older adults showed impaired recollection and familiarity relative to younger controls and individuals with MCI showed impaired recollection relative to healthy older adults. The recollection deficit in healthy older adults and persons with MCI and their impaired recognition of well-known items is compatible with the difficulty both groups have in encoding information in an elaborate manner. In turn, familiarity deficit could be related to impaired frontal functioning. Therefore, novelty of material has a differential impact on recognition in persons with age-related memory disorders.

Task switching capacities in persons with Alzheimer's disease and mild cognitive impairment.

Task switching is an executive capacity that relies on a set of separate components implicating a fronto-parietal network of brain areas. In the present study, different components implicated in task switching were assessed in persons with Alzheimer's disease (AD), persons with mild cognitive impairment (MCI), and their matched healthy controls. The procedure implicated presentation of a two-digit stimulus, and task switching involved either conceptual or spatial switching. Global switching was measured by comparing blocks that involved non-switch trials to blocks that included switch trials, whereas local switching was measured by comparing performance across single trials in the switch blocks. Furthermore, the paradigm measured practice effects. Persons with AD showed larger local and global switch cost than healthy controls suggesting that their deficits encompass both reconfiguration of new action sets and maintenance of potentially relevant tasks within working memory. Importantly, the deficit was large in spatial switching but negligible in the conceptual condition. Persons with MCI only showed global switching impairment, suggesting a deficit restricted to the concurrent maintenance of two relevant task sets, and as in AD, this impairment was limited to spatial switching. Interestingly, persons with MCI, but not AD patients, improved their switching capacities upon practice. These findings indicate that switching deficit is selective in both MCI and AD persons, and is thus supportive of the notion that different mechanisms are involved in task switching. The pattern across condition is coherent with a continuum between those two clinical groups.