Health numeracy and cognitive decline in advanced age

ABSTRACT

The study aimed at investigating health numeracy in cognitively well performing healthy participants aged from 50 to 95 years as well as in participants with cognitive impairment, but no dementia (CIND). In cognitively well performing participants (n = 401), demographic variables and cognitive abilities (executive functions, reading comprehension, mental calculation, vocabulary) were associated with health numeracy. Older age, lower education, female gender as well as lower cognitive functions predicted low health numeracy. The effect of older age was partly mediated by executive functions and calculation abilities. Participants with CIND (n = 51) performed significantly lower than healthy controls in health numeracy. The findings suggest that cognitively well performing old individuals have difficulties in understanding health-related numerical information. The risk of misunderstanding health-related numerical information is increased in persons with CIND. As these population groups are frequently involved in health care decisions, particular attention has to be paid to providing numerical information in comprehensible form.     

Functional decline in the early stages of Alzheimer's disease

At present most reports of functional decline in patients with Alzheimer's Disease (AD) are anecdotal, and few studies have objectively documented the course of the disease. This is a report of a 2-year follow-up of 15 AD patients characterized by mild functional impairment, and 22 age-, sex-, and education-matched control subjects. In a previous cross-sectional study of these 37 subjects and 16 AD patients with moderate functional impairment, we found that measures of memory and attention deficits accounted for much of the impairment observed in functional competence. The current longitudinal study found that these same initial assessments could be used to predict functional decline in the 15 mildly impaired patients. These patients were observed to decline to levels similar to those of the 16 moderate patients. In contrast, the control subjects exhibited little decline during the same period. These results both affirm that it is possible to diagnose AD in its mild form and demonstrate the validity of the initial diagnosis.     

Cluster analysis reveals distinct patterns of saccade impairment and their relation to cognitive profiles in Parkinson's disease

Saccade performance has been reported to be altered in Parkinson's disease (PD), however, with a large variability between studies as both motor and cognitive impairment interfere with oculomotor control. The aim of this study was to identify different patterns in saccade alterations in PD using a data-driven approach and to explore their relationship with cognitive phenotypes. Sixty-one participants with PD and 25 controls performed eye-tracking (horizontal and vertical prosaccades, antisaccades) and neuropsychological testing. Hierarchical cluster analysis was applied to the eye-tracking data to subsequently compare the clusters based on demographical, clinical and cognitive characteristics. The three identified clusters of saccade alterations differed in cognitive profiles from healthy controls, but not in PD-related motor symptoms or demographics. The rate of directive errors in the antisaccade task was increased in clusters 1 and 2. Further, cluster 1 was defined by a general disinhibition of reflexive saccades and executive dysfunction in the neuropsychological evaluation. In cluster 2, prolonged saccade latencies and hypometria were accompanied by multidomain cognitive impairment. The cluster 3 showed increased antisaccade latency and vertical hypometria despite lack of evidence for cognitive impairment. Our results suggest that there may be at least two opposing patterns of saccade alterations associated with cognitive impairment in PD, which may explain some of the contradictory results of previous studies.     

Predictors of cognitive change from preclinical to clinical Alzheimer's disease

We examined individual-difference variables in relation to the rate of change in global cognitive performance, measured by the MMSE, from 3 years prior to diagnosis of Alzheimer's disease (AD) to the time of diagnosis. The population-based sample consisted of 230 incident AD persons who were followed over a 3-year interval. The average annual decline in MMSE was 1.81 points. Being older and acquiring additional diseases during the 3 years preceding diagnosis predicted a faster rate of decline in global cognitive functioning. However, other individual difference variables such as sex, education, depression, vitamin levels (vitamin B12 and folic acid), apolipoprotein status, and social network did not precipitate the rate of decline in the preclinical phase of AD.     

Confrontation naming in Alzheimer's patients: relation to disease severity.

Reports of Alzheimer's disease patients in whom naming performance is disproportionate to other cognitive performances raise questions about the stage model, or dementia-severity level, for predicting naming performance. Thus, dementia severity as defined by Global Deterioration Scale ratings, Mini-Mental State Examination scores, and combinations of them was evaluated as a predictor of naming performance in 102 Alzheimer's patients and was found to account for approximately 1/3 of performance variability. Additional contributions from age at onset, duration, family history, and gender were negligible. Therefore, naming ability can be argued to have a subcomponent that is not subsumed by overall cognitive ability.     

Movements execution in amnestic mild cognitive impairment and Alzheimer's disease

We evaluated the relationship between motor and neuropsychological deficits in subjects affected by amnestic Mild Cognitive Impairment (aMCI) and early Alzheimer's Disease (AD). Kinematics of goal-directed movement of aMCI and AD subjects were compared to those of age-matched control subjects. AD showed a slowing down of motor performance compared to aMCI and controls. No relationships were found between motor and cognitive performances in both AD and aMCI. Our results suggest that the different motor behaviour between AD and aMCI cannot be related to memory deficits, probably reflecting the initial degeneration of parietal-frontal circuits for movement planning. The onset of motor dysfunction in early AD could represent the transition from aMCI to AD.     

Alzheimer's disease patients' cognitive status and course years prior to symptom recognition

This is a prospective examination of the cognitive performance and cognitive course of persons in an asymptomatic "preclinical" phase who eventually developed Alzheimer's disease (AD). We compared performances on the Mayo Cognitive Factor Scales (MCFS) of 20 persons in a neurologically normal cohort who subsequently developed AD to the performances of 60 persons who remained free of dementia symptoms. For the AD patients, exams occurred prior to the appearance of dementia symptoms (an average of 4.2 and 1.5 years prior to symptom onset). Results reveal strong group differences on learning and retention, with eventual AD patients scoring lower than controls years prior to reporting symptoms of the disease. There was no significant interaction effect (group x testing session) for memory retention, suggesting that memory decline in this preclinical period may be too slow to be a useful indicator of future AD. A significant interaction (but no group effect) was seen for verbal comprehension.     

Pantomime and imitation of limb gestures in relation to the severity of Alzheimer's disease

The present study was designed to investigate the relationship between performance of limb gestures and the severity of Alzheimer's disease (A.D.). Apraxia tends to occur at later stages of A.D., and the severity of apraxia has been shown to vary with the severity of A.D. dementia. Participants were 19 mild (including 9 with no cognitive impairment and 10 with mild impairment) and 18 moderate A.D. patients as well as 25 controls and they were asked to pantomime (P) or imitate (both concurrent (CI) and delayed (DI)), eight transitive gestures to assess praxis performance. Results indicated that the moderate patients performed less accurately than mild and non-impaired patients, and that across all groups, the imitation conditions were performed less accurately than pantomime, relative to controls. Correlational analyses revealed that MMSE scores were correlated with all three performance conditions suggesting that impaired praxis performance may relate to more global impairment. Finally, a frequency analysis was conducted to examine whether A.D. patients showed patterns of apraxia as described in Roy's model (1996). Results indicated that A.D. patients showed greatest impairment on pattern 7 (deficits in P, DI, and CI), reflecting late-stage gesture production, with a greater frequency of moderate patients exhibiting each apraxic pattern.     

Effects of age simulation and age on motor sequence learning: Interaction of age-related cognitive and motor decline

Aging is known to lead to decrements in sensory and cognitive functioning and motor performance. The purpose of the present experiment was twofold: a) We assessed the influence of wearing an age simulation suit on motor sequence learning, cognitive speed tasks and far visual acuity in healthy, younger adults. b) We evaluated the interaction of cognitive aging and declining motor sequence learning in older adults. In a between-subjects design we tested 11 younger adults (M_age = 23.6 years) without the age suit, 12 younger adults wearing the age suit (M_age = 23.2 years), and 23 older adults (M_age = 72.6 years). All participants learned a simple, spatial-temporal movement sequence on two consecutive days, and we assessed perceptual processing speed (Digit Symbol Substitution test and Figural Speed test) and far visual acuity. Wearing an age simulation suit neither affected the learning of the simple motor sequence nor the performance at the cognitive speed tasks in younger adults. However, far visual acuity suffered from wearing the suit. Younger adults with and without the suit showed better motor sequence learning compared to older adults. The significant correlations between the cognitive speed tests and the motor learning performance in older adults indicated that cognitive aging partially explains some of the variance in age-related motor learning deficits.     

阿尔兹海默症及轻度认知障碍静息态大尺度脑网络功能连接的改变

静息态功能磁共振成像作为非侵入性可视化成像方法, 且数据采集简便易行, 已成为探索阿尔兹海默症及轻度认知障碍脑功能变异的主要成像手段。近年来静息态研究显示在其前驱症状期轻度认知障碍阶段患者已显现出静息态脑网络的变异, 而阿尔兹海默症患者的网络改变更加弥散。研究发现随着病程推进, 患者显示出默认网络连接逐渐减弱以及额叶认知网络连接先增强后减弱的整体趋势。此外, 脑结构和功能网络的改变并非单向因果关系, 二者在病程进展中存在交互作用。未来研究可以从诊断的标志性神经通路、疗效的大尺度脑网络标记, 以及疾病的异质性等角度入手, 进一步探索静息态脑网络作为阿尔兹海默症诊断和病程监控指标的可能性。     

Cognitive plasticity in Alzheimer's disease patients receiving cognitive stimulation programs

The main purpose of this article is to examine whether cognitive plasticity increases after cognitive training in Alzheimer's disease patients. Twenty six patients participated in this study, all of them diagnosed with mild Alzheimer's disease, 17 of them received a cognitive training program during 6 months, and the other 9 were assigned to the control group. Participants were assigned to experimental or control conditions for clinical reasons. In order to assess cognitive plasticity, all patients were assessed before and after treatment with three subtests from the "Bateria de Evaluación de Potencial de Aprendizaje en Demencias" [Assessment Battery of Learning Potential in Dementia] (BEPAD). After treatment, Alzheimer's disease patients improved their performance in all the tasks assessing cognitive plasticity: viso-spatial memory, audio-verbal memory and verbal fluency. However, the cognitive plasticity scores of the patients in the control group decreased. In conclusion, this study showed that cognitive stimulation programs can improve cognitive functioning in mildly demented patients, and patients who do not receive any cognitive interventions may reduce their cognitive functioning.     

Focused attention deficits in patients with Alzheimer's disease and mild cognitive impairment

Reaction time (RT) tasks take various forms, and can assess psychomotor speed, (i.e., simple reaction time task), and focused attention (i.e., choice reaction time (CRT) task). If cues are provided before stimulus presentation (i.e., cued choice reaction time (CCRT) task), then a cueing effect can also be assessed. A limited number of studies have addressed the nature of focused attention impairments in Alzheimer's disease (AD). Additionally, it is unknown whether similar impairments occur in Mild Cognitive Impairment (MCI). The current study used three RT tasks to address the nature of focused attention impairments in AD and MCI subjects. The results suggest that there were significant CRT and CCRT differences in AD subjects when compared to NECs. Furthermore, slowed RTs were also present in the MCI group, which provides evidence for impaired focussed attention and the inability to benefit from a cue in both the MCI and AD groups. The implications of the impairments related to the MCI group could potentially prove useful in early diagnosis of cognitive impairments in the elderly.     

Clock drawing performance and brain morphology in mild cognitive impairment and Alzheimer's disease

The Clock Drawing Test (CDT) is a widely used instrument in the neuropsychological assessment of Alzheimer's disease (AD). As CDT performance necessitates several cognitive functions (e.g., visuospatial and constructional abilities, executive functioning), an interaction of multiple brain regions is likely. Fifty-one subjects with mild cognitive impairment, 23 with AD and 15 healthy controls underwent high-resolution magnetic resonance imaging. Optimized voxel-based morphometry (VBM) was performed to investigate the putative association between CDT performance and gray matter (GM) density throughout the entire brain. In the first step of analysis (p<.001, uncorrected), VBM revealed a reduced GM density in numerous cortical (temporal lobe, frontal lobe, parietal lobe, cerebellum) and subcortical (thalamus, basal ganglia) brain regions to be associated with poorer CDT performance. When corrected for multiple comparisons (p<.01), the associations remained significant predominantly in the left temporal and--less pronounced--the right temporal lobe. VBM demonstrated CDT performance to depend on the integrity of widely distributed cortical and subcortical areas in both brain hemispheres with accentuation in the left-sided temporal lobe region.     

Processing of mass/count information in Alzheimer's disease and mild cognitive impairment

This study examines the processing of a specific linguistic distinction, the mass/count distinction, in patients suffering from Alzheimer's disease (AD) and mild cognitive impairment (MCI). Fourteen AD and 10 MCI subjects were tested using a sentence grammaticality judgement task where grammaticality violations were caused by determiner-noun mismatches, as well as a sentence-picture matching task to assess their ability to access mass and count readings of dual nouns. Considerable heterogeneity was observed within each subject group, and performance across groups was almost identical. It is concluded that a combination of linguistic and attentional and/or learning factors are responsible for the range of impairments; specifically, a subset of subjects exhibit no linguistic nor attentional/learning impairment, another subset exhibit only an attentional and/or learning impairment but no linguistic impairment, and a third subset (comprising more than half of the subjects included in this study) exhibit a linguistic impairment. It is postulated that the latter group have difficulty processing sense extensions in metonymous nouns. It is further claimed that, at least within the limits of the study, language impairments can be of the same severity and nature across AD and MCI subjects.     

Different patterns of cognitive slowing produced by Alzheimer's disease and normal aging

Aging has previously been shown to produce a generalized proportional slowing of all cognitive operations. In contrast, the present results suggested that Alzheimer's disease produces a disproportionate reduction in the speed with which patients carry out one or more mental operations. The tasks that demented patients found particularly difficult involved either a self-directed search of their lexicon or the use of familiarity information.