Abstract Background In older adults, the extent to which performing a cognitive task when standing diminishes postural control is predictive of future falls and cognitive decline. The neurophysiology of such “dual-tasking” and its effect on postural control (i.e., dual-task cost) in older adults are poorly understood. The purpose of this study was to use electroencephalography (EEG) to examine the effects of dual-tasking when standing on brain activity in older adults. We hypothesized that compared to single-task “quiet” standing, dual-task standing would decrease alpha power, which has been linked to decreased motor inhibition, as well as increase the ratio of theta to beta power, which has been linked to increased attentional control. Methods Thirty older adults without overt disease completed four separate visits. Postural sway together with EEG (32-channels) were recorded during trials of standing with and without a concurrent verbalized serial subtraction dual-task. Postural control was measured by average sway area, velocity, and path length. EEG metrics included absolute alpha-, theta-, and beta-band powers as well as theta/beta power ratio, within six demarcated regions-of-interest: the left and right anterior, central, and posterior regions of the brain. Results Most EEG metrics demonstrated moderate-to-high between-day test–retest reliability (intra-class correlation coefficients > 0.70). Compared with quiet standing, dual-tasking decreased alpha-band power particularly in the central regions bilaterally (p = 0.002) and increased theta/beta power ratio in the anterior regions bilaterally (p < 0.001). A greater increase in theta/beta ratio from quiet standing to dual-tasking in numerous demarcated brain regions correlated with greater dual-task cost (i.e., absolute increase, indicative of worse performance) to postural sway metrics (r = 0.45–0.56, p < 0.01). Lastly, participants who exhibited greater alpha power during dual-tasking in the anterior-right (r = 0.52, p < 0.01) and central-right (r = 0.48, p < 0.01) regions had greater postural sway velocity during dual-tasking. Conclusion In healthy older adults, alpha power and theta/beta power ratio change with dual-task standing. The change in theta/beta power ratio in particular may be related to the ability to regulate standing postural control when simultaneously performing unrelated, attention-demanding cognitive tasks. Modulation of brain oscillatory activity might therefore be a novel target to minimize dual-task cost in older adults.
Abstract Background Alzheimer’s disease (AD) affects over 55 million people worldwide and is characterized by abnormal deposition of amyloid‐β and tau in the brain causing neuronal damage and disrupting transmission within brain circuits. Episodic memory loss, executive deficits, and depression are common symptoms arising from altered function in spatially distinct brain circuits that greatly contribute to disability. Transcranial electrical stimulation (tES) can target these circuits and has shown promise to relieve specific symptoms. However, previous trials focused on a single symptom and have been limited by poor quantification of induced electric fields (E‐field) in the intended cortical target(s). The studies aim to provide multi‐symptom relief to older adults with AD by combining two types of tES. Method Fourteen participants diagnosed with mild cognitive impairment (MCI) or early dementia due to AD were recruited as part of two studies (Table 1). Optimization of tES was performed by modeling the normal component of the induced E‐field (En) to target the left dorsolateral prefrontal cortex (DLPFC, Brodmann area 46) with transcranial direct current stimulation (tDCS) and to target the left angular gyrus (AG, Brodmann areas 39/40) with transcranial alternating current stimulation (tACS – 40 Hz) (Figure 1). Participants received daily stimulation sessions for four weeks at home, with baseline, post‐intervention, and 3‐month follow‐up assessments. E‐field modeling using MRIs evaluates behavioral effects' dependency on E‐field induced by tDCS and tACS in DLPFC and AG. Result Both studies showed excellent adherence to a home‐based, multi‐symptom tDCS/tACS intervention. To date, out of 280 scheduled sessions across 14 participants, 278 were completed, with a 99% adherence rate. The most common side effects were mild and transient (Table 2). Structural MRI scans were used to quantify E‐field modeling in target brain regions. Conclusion The studies demonstrate the safety, feasibility, and adherence of a remote‐supervised, caregiver‐led home‐based intervention combining tDCS and tACS to target two distinct brain networks and thus induce a more meaningful clinical impact by reducing distinct disabilities in AD. Quantifying the induced E‐field will provide data to assess the mediating effects of E‐field on treatment outcomes, yielding critical insights to enable future larger‐scale trials.
Abstract Background Cluster headache (CH) is a trigeminal autonomic cephalalgia (TAC) characterized by a highly disabling headache that negatively impacts quality of life and causes limitations in daily functioning as well as social functioning and family life. Since specific measures to assess the quality of life (QoL) in TACs are lacking, we recently developed and validated the cluster headache quality of life scale (CH-QoL). The sensitivity of CH-QoL to change after a medical intervention has not been evaluated yet. Methods This study aimed to test the sensitivity to change of the CH-QoL in CH. Specifically we aimed to (i) assess the sensitivity of CH-QoL to change before and following deep brain stimulation of the ventral tegmental area (VTA-DBS), (ii) evaluate the relationship of changes on CH-QoL with changes in other generic measures of quality of life, as well as indices of mood and pain. Ten consecutive CH patients completed the CH-QoL and underwent neuropsychological assessment before and after VTA-DBS. The patients were evaluated on headache frequency, severity, and load (HAL) as well as on tests of generic quality of life (Short Form-36 (SF-36)), mood (Beck Depression Inventory, Hospital Anxiety and Depression Rating Scale), and pain (McGill Pain Questionnaire, Headache Impact Test, Pain Behaviour Checklist). Results The CH-QoL total score was significantly reduced after compared to before VTA-DBS. Changes in the CH-QoL total score correlated significantly and negatively with changes in HAL, the SF-36, and positively and significantly with depression and the evaluative domain on the McGill Pain Questionnaire. Conclusions Our findings demonstrate that changes after VTA-DBS in CH-QoL total scores are associated with the reduction of frequency, duration, and severity of headache attacks after surgery. Moreover, post VTA-DBS improvement in CH-QoL scores is associated with an amelioration in quality of life assessed with generic measures, a reduction of depressive symptoms, and evaluative pain experience after VTA-DBS. These results support the sensitivity to change of the CH-QoL and further demonstrate the validity and applicability of CH-QoL as a disease specific measure of quality of life for CH.
Abstract The Healthy Aging Initiative (HAI) is a Boston-based longitudinal observational study assessing functional ability and well-being in 55+ adults residing in independent-living senior communities. Participants undergo assessments to evaluate modifiable risk factors for disability and dementia: mobility, cognition, strength, functional status, lifestyle factors, and mental wellness. Timely feedback/results are provided to empower meaningful changes. To gain insight into factors impacting functional ability, all participants’ data through Year 1 (N=173) were aggregated and key modifiable risk factors analyzed, revealing compelling trends across age groups and sex. Trends included sex differences among participants aged 80-84 years in the memory domain (Males 29% impaired (n=14); Females 13% impaired (n=24)). However, in the 85-89 age group these differences were no longer observed (Males 42% impaired (n=12); Females 39% impaired (n=23)), suggesting older women may “catch up” in impairment by their late 80’s. In mobility, females with high fall risk nearly doubled from age 75-79 to 80-84 (33% (n=18) to 63% (n=30)), while males in these age groups had the opposite effect (56% (n=9) to 27% (n=22)), indicating males who remain agile until the age of 80 may delay mobility decline. In lifestyle factors, it’s important to look at a domain from multiple perspectives. For instance, 68% of participants (n=132) report following recommended exercise guidelines, while 52% also report spending at least 6 hours sitting daily (n=101). Full results will be presented. As HAI expands and participants repeat assessments annually, critical insights may be obtained, creating a blueprint for translational clinical research in healthy ageing.
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