Associations of Lower Extremity Peripheral Nerve Impairment and Risk of Dementia in Black and White Older Adults

The association of chemotherapy-induced peripheral neuropathy with reduced executive function in chemotherapy-treated cancer survivors: A cross-sectional study

INTRODUCTION

Chemotherapy-induced peripheral neuropathy (CIPN) is common and disabling among cancer survivors. Little is known about the association of CIPN with other measures of the nervous system's integrity, such as executive dysfunction. We compared measures of executive function in older chemotherapy-treated cancer survivors with and without CIPN.

MATERIALS AND METHODS

This cross-sectional study enrolled 50 chemotherapy-treated cancer survivors (65.6 ± 11.5 years, 88% female) post-chemotherapy treatment who were previously referred for outpatient rehabilitation at the request of the cancer survivor or a medical provider. Twenty-two participants (44%) had CIPN defined by patient-reported distal paresthesia or numbness, which began with chemotherapy and continued to the time of cognitive testing. Measures of executive function included Trails-B, Stroop, and rapid reaction accuracy (RRA) and were evaluated between cancer survivors with and without CIPN using t-tests. Multivariable models were then used to determine whether CIPN was an independent determinant of the measures of executive function (Trails-B, Stroop Incongruent, and RRA). Models were adjusted for age, sex, history of anxiety, and benzodiazepine use due to their known associations with CIPN and executive function.

RESULTS

Cancer survivors with CIPN (CIPN+) had reduced executive function compared to survivors without CIPN (CIPN-) on Trails-B (CIPN+: 84.9 s ± 44.1 s, CIPN-: 59.1 s ± 22.5 s, p = 0.01), Stroop (CIPN+: 100.6 s ± 38.2 s, CIPN-: 82.1 s ± 17.3 s, p = 0.03), and RRA (CIPN+: 60.3% ± 12.9%, CIPN-: 70.6% ± 15.7%, p = 0.01). There were no differences in cancer stage severity or functional status by patient report or sit-to-stand function. The association between CIPN and reduced executive function was found in multivariable models after adjusting for age, sex, anxiety, and benzodiazepine use for Trails-B (ß:17.9, p = 0.046), Stroop (ß:16.9, p = 0.02), and RRA (ß:-0.072, p = 0.03).

DISCUSSION

In this population, CIPN is associated with reduced executive function in older cancer survivors treated with chemotherapy. Future research is required to further understand this preliminary association, the causality, and the potential risk factors.

Association Between Multisensory Impairment and Depression Among Older Adults: A Population-Based Analysis

OBJECTIVE

In this study, we examine how impairments in vision, hearing, touch, and olfaction relate to depression in older adults, considering both individual and multisensory impairments (MSIs).

STUDY DESIGN

Analysis of cross-sectional data from a longitudinal investigation involving black and white older adults aged 70 to 79 at enrollment.

SETTING

We studied 1640 black and white participants in the Health ABC study using complete sensory evaluation data from years 3 to 5.

METHODS

Our MSI assessment utilized data obtained for visual acuity, hearing perception, olfactory performance, and tactile function. We performed multivariable logistic regression analyses to examine the associations between the presence of individual and MSIs and depression which was defined as the presence of antidepressants prescribed for depression, or a Center for Epidemiological Studies Depression Scale score of greater than 10.

RESULTS

We observed a possible dose-response relationship between the number of sensory impairments and depression. In adjusted models, when compared to no impairments, vision (odds ratio [OR] = 1.45, 95% confidence interval [CI]: 1.09-1.93) and hearing impairments (OR = 1.49, 95% CI: 1.11-1.99) were significantly associated with depression, whereas olfaction (OR = 1.11, 95% CI: 0.83-1.47) and tactile impairments (OR = 1.28, 95% CI: 0.96-1.70) were not. Participants with 3 sensory impairments had a higher rate of depression (OR = 2.05, 95% CI: 1.22-3.54) compared to those without impairments, and this risk increased further for those with 4 sensory impairments (OR = 2.95, 95% CI: 1.48-5.88).

CONCLUSION

The findings suggest that individuals with MSI represent a high-risk population for depression, warranting close monitoring to screen for depression. The study emphasizes the importance of considering multiple sensory impairments in the context of mental health and supports the early identification and monitoring of depression in this population.

Meta-Analysis-Based Comparison of Annual Fall Risk between Older Adults with Alzheimer's Disease and Mild Cognitive Impairment

Background

Falls are a primary cause of injuries and hospitalization in older adults. It has been reported that cognitive impairments and dementia can increase fall risk in the older population; however, it remains unknown if fall risk differs among subgroups of dementia. This meta-analysis summarized previous studies reporting the annual fall risk of people with Alzheimer's disease (AD) or mild cognitive impairment (MCI) and compared the fall risk between these two groups of people with dementia.

Methods

Thirty-five studies enrolling 7844 older adults with AD or MCI were included. The annual fall prevalence and average number of falls of the included studies were meta-analyzed and compared by random-effects models with inverse variance weights.

Results

The annual fall prevalence in people with AD (43.55%) was significantly higher than MCI (35.26%, p < 0.001). A χ2 test indicated that the pooled fall prevalence is significantly higher in people with AD than MCI χ2 = 158.403, p < 0.001). Additionally, the yearly average number of falls in AD was higher than in MCI (1.30 vs 0.77 falls/person).

Conclusions

The results showed that older people with AD experience a higher annual fall prevalence with a larger number of falls than older adults with MCI. The results suggested that the fall risk measurements should be reported separately between people with AD and MCI. The findings could provide preliminary guidance for the identification of individuals with dementia who experience a high fall risk.

Epidemiology and Functional Impact of Early Peripheral Neuropathy Signs in Older Adults from a General Population

INTRODUCTION

Peripheral neuropathy (PN) becomes more common with increasing life expectancy, but general population prevalence estimates are lacking. We investigated an epidemiological distribution of signs of PN among 2,996 community-dwelling participants in Good Aging in Skåne Study, age 60-97, and their impact on physical and autonomic function.

METHODS

Signs of PN were measured with Utah Early Neuropathy Scale (UENS). Associations between UENS and physical tests, pain, and dysautonomic phenomena were calculated for each sex, adjusted for age, with estimated marginal means (EMM) and odds ratios (ORs) in four UENS quantiles (Q1-Q4).

RESULTS

Participants in Q4 had worse EMM for: time to complete Timed Up and Go test (Q4-Q1: male 10.8-9.6 s; female 11.7-10.2 s), 15 m Walk test (Q4-Q1: male 11.1-9.9 s; female 11.2-10.4 s), and fewer repetitions in Step test (Q4-Q1: male 15.2-17.0 steps; female 14.5-15.8 steps). Higher OR of failing one-leg balance 60 s test {male 2.5 (confidence interval [CI] 95%: 1.7-3.8); female 2.1 (1.1-3.2)}, Foam Pad Balance test (male 4.6 [CI 95%: 3.2-6.7]; female 1.8 [1.3-2.6]), and lower physical quality of life were seen in Q4 compared to Q1. Participants in Q4 had higher OR for walking aid usage, falls, fear of falling, pain, and urinary incontinence, while in males, higher OR for orthostatic intolerance, fecal incontinence, and constipation.

CONCLUSIONS

In a general population, 20-25% of older adults who have highest UENS scores, a sensitive measure of early PN, express slower gait, worse balance, lower quality of life, pain, falls and fear of falling, and autonomic symptoms.

Association between spill-related exposure to fine particulate matter and peripheral motor and sensory nerve function among oil spill response and cleanup workers following the Deepwater Horizon oil spill

BACKGROUND

Burning/flaring of oil/gas during the Deepwater Horizon oil spill response and cleanup (OSRC) generated high concentrations of fine particulate matter (PM_2.5). Personnel working on the water during these activities may have inhaled combustion products. Neurologic effects of PM_2.5 have been reported previously but few studies have examined lasting effects following disaster exposures. The association of brief, high exposures and adverse effects on sensory and motor nerve function in the years following exposure have not been examined for OSRC workers.

OBJECTIVES

We assessed the relationship between exposure to burning/flaring-related PM_2.5 and measures of sensory and motor nerve function among OSRC workers.

METHODS

PM_2.5 concentrations were estimated from Gaussian plume dispersion models and linked to self-reported work histories. Quantitative measures of sensory and motor nerve function were obtained 4-6 years after the disaster during a clinical exam restricted to those living close to two clinics in Mobile, AL or New Orleans, LA (n = 3401). We obtained covariate data from a baseline enrollment survey and a home visit, both in 2011-2013. The analytic sample included 1186 participants.

RESULTS

We did not find strong evidence of associations between exposure to PM_2.5 and sensory or motor nerve function, although there was a suggestion of impairment based on single leg stance among individuals with high exposure to PM_2.5. Results were generally consistent whether we examined average or cumulative maximum exposures or removed individuals with the highest crude oil exposures to account for co-pollutant confounding. There was no evidence of exposure-response trends.

IMPACT STATEMENT

Remediating environmental disasters is essential for long-term human and environmental health. During the Deepwater Horizon oil spill disaster, burning and flaring of oil and gas were used to remove these pollutants from the environment, but led to potentially high fine particulate matter exposures for spill response workers working on the water. We investigate the potential adverse effects of these exposures on peripheral nerve function; understanding the potential health harm of remediation tactics is necessary to inform future clean up approaches and protect human health.

Neurological Implications of Vitamin B12 Deficiency in Diet: A Systematic Review and Meta-Analysis

Background: Vitamin B12 is one of the most important B-Vitamins that the human body needs on a daily basis, the lack of which can precipitate several neurological issues. Objectives: This systematic aimed to investigate the neurological implications of Vitamin B12 deficiency and the effects when B12 levels were corrected in susceptible individuals. Methods: The databases PubMed-MEDLINE, Web of Science, Cochrane, and Scopus were all searched using pertinent keywords, reference searches, and citation searches. The terms used to access the database were “Cognition”, “Dietary patterns”, “Neurology”, “Nutritional profile”, and “Vitamin B12”. Results: Vitamin B12 was shown to noticeably improve cognition and other neurological parameters in the short term in older adults and the short-to-medium term in children; however, there was no perceived increase/improvement when the Vitamin was administered in the longer term, either alone or in conjunction with other similar nutritional interventions. Conclusion: Vitamin B12’s role in the improvement of neurological functions over a long-term period remains somewhat inconclusive to date, as the majority of our selected control trials did not display much correlation between the two factors. However, Vitamin B12 did improve cognition levels in both children and older adults over a short course of administration.

Demand Coupling Drives Neurodegeneration: A Model of Age-Related Cognitive Decline and Dementia

The societal burden of Alzheimer's Disease (AD) and other major forms of dementia continues to grow, and multiple pharmacological agents directed towards modifying the pathological "hallmarks" of AD have yielded disappointing results. Though efforts continue towards broadening and deepening our knowledge and understanding of the mechanistic and neuropathological underpinnings of AD, our previous failures motivate a re-examination of how we conceptualize AD pathology and progression. In addition to not yielding effective treatments, the phenotypically heterogeneous biological processes that have been the primary area of focus to date have not been adequately shown to be necessary or sufficient to explain the risk and progression of AD. On the other hand, a growing body of evidence indicates that lifestyle and environment represent the ultimate level of causation for AD and age-related cognitive decline. Specifically, the decline in cognitive demands over the lifespan plays a central role in driving the structural and functional deteriorations of the brain. In the absence of adequate cognitive stimulus, physiological demand-function coupling leads to downregulation of growth, repair, and homeostatic processes, resulting in deteriorating brain tissue health, function, and capacity. In this setting, the heterogeneity of associated neuropathological tissue hallmarks then occurs as a consequence of an individual's genetic and environmental background and are best considered downstream markers of the disease process rather than specific targets for direct intervention. In this manuscript we outline the evidence for a demand-driven model of age-related cognitive decline and dementia and why it mandates a holistic approach to dementia treatment and prevention that incorporates the primary upstream role of cognitive demand.

Different profiles of neurocognitive impairment in patients with hepatitis B and C virus infections

The direct impact of chronic hepatitis B and hepatitis C on neurocognition remains elusive due to the frequent comorbidities, and the domains of the neurocognitive functions affected have rarely been investigated comprehensively. We cross-sectionally assessed the neurocognitive functions of the individuals with chronic hepatitis B, chronic hepatitis C, treated chronic hepatitis C with a sustained virologic response, and their healthy control counterparts. Laboratory examinations were used to investigate the impact of inflammation on neurocognition, exclude the medical conditions that could interfere with neurocognition assessment, and assess liver function and fibrotic severity of the liver of the participants. This study found the detrimental impact of chronic hepatitis B on language and executive functions. In contrast, individuals with chronic hepatitis C showed deficits in executive functions, psychomotor speed, memory, and attention. Successful elimination of hepatitis C resulted in improved liver function, but not neuropsychological test performance. Moreover, erythrocyte sedimentation rate level was found to mediate the deficits in the attention of individuals with chronic hepatitis C. These results demonstrate the neurocognitive deficits and the difference in the profiles of neurocognitive deficits in individuals with chronic hepatitis B and chronic hepatitis C. Our study also provided results suggesting the mediation by systemic inflammation on the attention deficit in individuals with chronic hepatitis C.