Dissociation of Executive and Attentional Elements of the Digit Span Task in a Population of Older Adults: A Latent Class Analysis

A short and simple bedside test to detect cognitive fluctuations in patients with dementia with Lewy bodies

BACKGROUND AND PURPOSE

The establishment of cognitive fluctuations is important when dementia with Lewy bodies (DLB) is suspected but can be especially difficult in the absence of a caregiver who lives with the patient. We examined the possibility of using fluctuating scores on a forward (FDS) and a backward digit span (BDS) test as a marker for cognitive fluctuation.

METHODS

Patients with DLB (21), other forms of dementia (14 with Alzheimer's disease, 8 with vascular dementia) and 20 controls were asked to perform an FDS and BDS twice, with an interval of 20 min.

RESULTS

Seventy percent of patients with DLB showed evidence of cognitive fluctuations for at least one test, while less than 10% of controls and patients with other dementias did. Evidence of cognitive fluctuations on at least one of both tests classified 83% of patients correctly (i.e. DLB or not), with a sensitivity of 70% and a specificity of 90%.

CONCLUSIONS

Repeated forward and backward digit span tests seem a valid, short, easy and inexpensive bedside tool to detect cognitive fluctuations in the diagnostic work-up of DLB, even in the absence of a caregiver, which limits the use of questionnaires.

Exercise engagement drives changes in cognition and cardiorespiratory fitness after 8 weeks of aerobic training in sedentary aging adults at risk of cognitive decline

Background

With our aging population, many individuals are at risk of developing age-related cognitive decline. Physical exercise has been demonstrated to enhance cognitive performance in aging adults. This study examined the effects of 8 weeks of aerobic exercise on cognitive performance and cardiorespiratory fitness in sedentary aging adults at risk for cognitive decline.

Methods

Fifty-two participants (age 62.9 ± 6.8, 76.9% female) engaged in eight weeks of moderate-to high-intensity exercise (19 in-person, 33 remotely). Global cognition was measured by the Repeatable Battery for the Assessment of Neuropsychological Status, the Delis-Kaplan Executive Function System, and the Digit Span subtest of the Wechsler Adult Intelligence Scale (WAIS) Fourth Edition. Cardiorespiratory fitness was measured via heart rate recovery at minute 1 (HRR1) and 2 (HRR2), and exercise engagement (defined as percent of total exercise time spent in the prescribed heart rate zone). We measured pre and post changes using paired t-tests and mixed effects models, and investigated the association between cardiorespiratory and cognitive performance using multiple regression models. Cohen's d were calculated to estimate effect sizes.

Results

Overall, 63.4 % of participants demonstrated high engagement (≥ 70% total exercise time spent in the prescribed heart rate zone). There were significant pre-post improvements in verbal fluency and verbal memory, and a significant decrement in working memory, but these were associated with small effect sizes (Cohen's d <0.5). Concerning cardiorespiratory fitness, there was a pre-to-post significant improvement in HRR1 (p = 0.01, d = 0.30) and HRR2 (p < 0.001, d = 0.50). Multiple regressions revealed significant associations between cardiorespiratory and cognitive performance, but all were associated with small effect sizes (Cohen's d < 0.5). Interestingly, there were significant between-group differences in exercise engagement (all p < 0.001), with remote participants demonstrating greater exercise engagement than in-person participants.

Conclusion

Improvements in cognition and cardiorespiratory fitness were observed after 8 weeks of moderate to high-intensity exercise in aging adults. These results suggest that committing to a regular exercise regimen, even for a brief two-month period, can promote improvements in both cardiorespiratory fitness and cognitive performance, and that improvements are driven by exercise engagement.

Executive function and attentional bias as serial mediators in the relationship between frailty and depressive symptoms among older inpatients: A cross-sectional study

AIMS AND OBJECTIVES

To examine the serial mediating effect of executive function and attentional bias in the relationship between frailty and depressive symptoms.

BACKGROUND

Although the role of frailty in predicting depression has been well documented, the underlying mechanisms remain unclear.

DESIGN

A cross-sectional study was conducted with 667 older inpatients aged 60-90 years in the internal medicine wards of a hospital in China.

METHODS

Attentional bias, frailty and depressive symptoms were assessed using the Attention to Positive and Negative Information Scale, the Physical Frailty Phenotype and the 5-item Geriatric Depression Scale. Executive function was measured using 3 tests, including digital backward, category Verbal Fluency Test and Trail Making Test. The study followed the STROBE guideline.

RESULTS

The latent profile analysis (LPA) identified four patterns of attentional bias, namely "no positive bias & no negative bias" (class 1, 9.3%), "minor positive bias & no negative bias" (class 2, 48.0%), "major positive bias & minor negative bias" (class 3, 25.6%) and "major positive bias & no negative bias" (class 4, 17.1%). Regression analysis found that frailty was associated with depressive symptoms. Frailty was also negatively associated with executive function, which was a protective factor for attentional bias class 1, 2 and 3 with reference to class 4. Attentional bias class 1 and 2 but not class 3 was associated with depressive symptoms with reference to class 4. The joint significance test confirmed executive function and attentional bias as serial mediators linking frailty to depressive symptoms.

DISCUSSION

Unlike robust older adults who have the age-related positivity effect, frail older adults have attentional bias deficits due to executive dysfunction, and consequently experience clinically relevant depressive symptoms.

RELEVANCE TO CLINICAL PRACTICE

Healthcare providers should take executive function training and attentional bias regulation into consideration to reduce the detrimental effects of frailty on emotional well-being.

Harnessing Neuroplasticity to Promote Brain Health in Aging Adults: Protocol for the MOVE-Cog Intervention Study

Background

Extensive evidence supports a link between aerobic exercise and cognitive improvements in aging adults. A major limitation with existing research is the high variability in cognitive response to exercise. Our incomplete understanding of the mechanisms that influence this variability and the low adherence to exercise are critical knowledge gaps and major barriers for the systematic implementation of exercise for promoting cognitive health in aging.

Objective

We aimed to provide an in-person and remotely delivered intervention study protocol with the main goal of informing the knowledge gap on the mechanistic action of exercise on the brain by characterizing important mechanisms of neuroplasticity, cardiorespiratory fitness response, and genetics proposed to underlie cognitive response to exercise.

Methods

This is an open-label, 2-month, interventional study protocol in neurologically healthy sedentary adults. This study was delivered fully in-person and in remote options. Participants underwent a total of 30 sessions, including the screening session, 3 pretest (baseline) assessments, 24 moderate-to-vigorous aerobic exercise sessions, and 3 posttest assessments. We recruited participants aged 55 years and above, sedentary, and cognitively healthy. Primary outcomes were neuroplasticity, cognitive function, and cardiorespiratory fitness. Secondary outcomes included genetic factors, endothelium function, functional mobility and postural control, exercise questionnaires, depression, and sleep. We also explored study feasibility, exercise adherence, technology adaptability, and compliance of both in-person and remote protocols.

Results

The recruitment phase and data collection of this study have concluded. Results are expected to be published by the end of 2021 or in early 2022.

Conclusions

The data generated in these studies will introduce tangible parameters to guide the development of personalized exercise prescription models for maximal cognitive benefit in aging adults. Successful completion of the specific aims will enable researchers to acquire the appropriate expertise to design and conduct studies by testing personalized exercise interventions in person and remotely delivered, likely to be more effective at promoting cognitive health in aging adults.

Trial Registration

ClinicalTrials.gov NCT03804528; http://clinicaltrials.gov/ct2/show/NCT03804528

International Registered Report Identifier (IRRID)

RR1-10.2196/33589

Characteristics of cognitive impairment in adult asymptomatic moyamoya disease

Background

Cognitive impairment in adult moyamoya disease (MMD) is thought to be the result of ischemic stroke; however, the presence and extent of cognitive decline in asymptomatic patients is unclear.

Methods

After classification using T2-weighted fluid attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI), a total of 19 MMD patients with a history of cerebral infarction, 21 asymptomatic MMD patients, and 20 healthy controls matched for age, sex, and years of education were prospectively included in this study. A detailed neuropsychological evaluation of two moyamoya subgroups and normal controls was conducted.

Results

Asymptomatic patients showed varying degrees of decline in intelligence (Raven’s Standard Progressive Matrices, P = 0.001), spatial imagination (mental rotation, P = 0.014), working memory (verbal working memory-backward digit span, P = 0.011), and computational ability (simple subtraction, P = 0.014; complex subtraction, P < 0.001) compared with normal controls. MMD patients with cerebral infarction had more severe impairment in complex arithmetic (P = 0.027) and word short-term memory (P = 0.01) than those without symptoms.

Conclusion

In asymptomatic MMD patients, a variety of cognitive impairment precedes the onset of clinical symptoms such as cerebral infarction, which may be a long-term complication of conservative treatment.