Control In Older Adults Research Articles

Older adults and stroke survivors are steadier when gazing down.

Advanced age and brain damage have been reported to increase the propensity to gaze down while walking, a behavior that is thought to enhance stability through anticipatory stepping control. Recently, downward gazing (DWG) has been shown to enhance postural steadiness in healthy adults, suggesting that it can also support stability through a feedback control mechanism. These results have been speculated to be the consequence of the altered visual flow when gazing down. The main objective of this cross-sectional, exploratory study was to investigate whether DWG also enhances postural control in older adults and stroke survivors, and whether such effect is altered with aging and brain damage. Posturography of older adults and stroke survivors, performing a total of 500 trials, was tested under varying gaze conditions and compared with a cohort of healthy young adults (375 trials). To test the involvement of the visual system we performed spectral analysis and compared the changes in the relative power between gaze conditions. Reduction in postural sway was observed when participants gazed down 1 and 3 meters ahead whereas DWG towards the toes decreased steadiness. These effects were unmodulated by age but were modulated by stroke. The relative power in the spectral band associated with visual feedback was significantly reduced when visual input was unavailable (eyes-closed condition) but was unaffected by the different DWG conditions. Like young adults, older adults and stroke survivors better control their postural sway when gazing down a few steps ahead, but extreme DWG can impair this ability, especially in people with stroke.

Smooth pursuit eye movements contribute to anticipatory force control during mechanical stopping of moving objects.

When stopping a closing door or catching an object, humans process the motion of inertial objects and apply reactive limb force over short period to interact with them. One way in which the visual system processes motion is through extraretinal signals associated with smooth pursuit eye movements (SPEMs). We conducted three experiments to investigate how SPEMs contribute to anticipatory and reactive hand force modulation when interacting with a virtual object moving in the horizontal plane. We hypothesized that SPEM signals are critical for timing motor responses, anticipatory control of hand force, and task performance. Participants held a robotic manipulandum and attempted to stop an approaching simulated object by applying a force impulse (area under force-time curve) that matched the object's virtual momentum upon contact. We manipulated the object's momentum by varying either its virtual mass or its speed under free gaze or constrained gaze conditions. We examined gaze variables, the timing of hand motor responses, anticipatory force control, and overall task performance. Our results show that when participants were fixated at a designated location instead of following objects with SPEM, anticipatory modulation of hand force before contact decreased. However, constraining gaze by asking participants to fixate did not seem to affect the timing of the motor response or the task performance. Together, these results suggest that SPEMs may be important for anticipatory control of hand force before contact and may also play a critical role in anticipatory stabilization of limb posture when humans interact with moving objects.NEW & NOTEWORTHY We show for the first time that smooth pursuit eye movements (SPEMs) play a role in the modulation of anticipatory control of hand force to stabilize posture against contact forces. SPEMs are critical for tracking moving objects, facilitate processing motion of moving objects, and are impacted during aging and in many neurological disorders, such as Alzheimer's disease and multiple sclerosis. These results provide a novel basis to probe how changes in SPEMs could contribute to deficient limb motor control in older adults and patients with neurological disorders.

Placebo effect on gait: a way to reduce the dual-task cost in older adults

The ability to perform two tasks simultaneously is essential for daily activities. In older adults, this ability is markedly reduced, as evidenced by the dual-task cost on gait. Preliminary evidences indicate that the dual-task cost can be influenced by different types of manipulations. Here, we explored the effectiveness of a new approach to reduce the dual-task cost, based on the placebo effect, a psychobiological phenomenon whereby a positive outcome follows the administration of an inert device thought to be effective. Thirty-five healthy older adults were asked to walk on a sensorized carpet (single-task condition) and to walk while counting backward (dual-task condition) in two sessions (pre-test and post-test). A placebo group, randomly selected, underwent sham transcranial direct current stimulation over the supraorbital areas between sessions, along with information about its positive effects on concentration and attention. A control group did not receive any intervention between sessions. The dual-task cost was significantly reduced in the placebo group at the post-test session compared to the pre-test for several gait parameters (Cohen's d > 1.43). At the post-test session, the dual-task cost was also lower in the placebo group than in the control group (d > 0.73). Cognitive (number of subtractions and number of errors) and subjective (perceived mental fatigability) variables remained stable across sessions. The reduced dual-task cost in the placebo group could indicate the ability to re-establish the allocation of attentional resources between tasks. These findings could contribute to the development of cognitive strategies that leverage positive expectations to boost motor control in older adults.

Exploring how arm movement moderates the effect of task difficulty on balance performance in young and older adults

Emerging evidence highlights that arm movements exert a substantial and functionally relevant contribution on quiet standing balance control in young adults. Ageing is associated with “non-functional” compensatory postural control strategies (i.e., lower limb co-contraction), which in turn, may increase the reliance on an upper body strategy to control upright stance. Thus, the primary purpose of this study was to compare the effects of free versus restricted arm movements on balance performance in young and older adults, during tasks of different difficulty. Fifteen young (mean ± SD age; 21.3 ± 4.2 years) and fifteen older (mean ± SD age; 73.3 ± 5.0 years) adults performed bipedal, semi-tandem and tandem balance tasks under two arm position conditions: restricted arm movements and free arm movements. Centre of pressure (COP) amplitude and frequency were calculated as indices of postural performance and strategy, respectively. Especially in older adults, restriction of arm movement resulted in increased sway amplitude and frequency, which was primarily observed for the mediolateral direction. Further, increasing balance task difficulty raised the arm restriction cost (ARC; a new measure to quantify free vs. restricted arm movement differences in postural control) that was more prominent in older adults. These findings indicate the ARC provides a measure of reliance on the upper body for balance control and that arm movement is important for postural control in older adults, especially during tasks of greater difficulty.

Cerebello-cortical functional connectivity may regulate reactive balance control in older adults with mild cognitive impairment.

Older adults with mild cognitive impairment (OAwMCI) experience a two-fold increased risk of falling compared to their cognitively intact counterparts. This increased risk could be attributed to impairments in balance control mechanisms (both volitional and reactive), however, the exact neural substrates contributing to the balance impairments remain unclear. While changes in functional connectivity (FC) networks in volitional balance control tasks have been well highlighted, the relationship between these changes and reactive balance control has not been examined. Therefore, this study aims to explore the relationship between FC networks of the brain obtained during resting state fMRI (no visualization or active task performed) and behavioral measures on a reactive balance task in OAwMCI. Eleven OAwMCI (< 25/30 on MoCA, > 55 years) underwent fMRI and were exposed to slip-like perturbations on the Activestep treadmill. Postural stability, i.e., dynamic center of mass motion state (i.e., its position and velocity) was computed to determine reactive balance control performance. The relationship between reactive stability and FC networks was explored using the CONN software. OAwMCI with greater FC in default mode network-cerebellum (r2 = 0.43, p < 0.05), and sensorimotor-cerebellum (r2 = 0.41, p < 0.05) network exhibited lower reactive stability. Further, people with lower FC in middle frontal gyrus-cerebellum (r2 = 0.37, p < 0.05), frontoparietal-cerebellum (r2 = 0.79, p < 0.05) and cerebellar network-brainstem (r2 = 0.49, p < 0.05) exhibited lower reactive stability. Older adults with mild cognitive impairment demonstrate significant associations between reactive balance control and cortico-subcortical regions involved in cognitive-motor control. Results indicate that the cerebellum and its communications with higher cortical centers could be potential substrates contributing to impaired reactive responses in OAwMCI.

Paradoxical improvement of cognitive control in older adults under dual-task walking conditions is associated with more flexible reallocation of neural resources: A Mobile Brain-Body Imaging (MoBI) study

Combining walking with a demanding cognitive task is traditionally expected to elicit decrements in gait and/or cognitive task performance. However, it was recently shown that, in a cohort of young adults, most participants improved performance when walking was added to performance of a Go/NoGo response inhibition task. The present study aims to extend these previous findings to an older adult cohort, to investigate whether this improvement when dual-tasking is observed in healthy older adults. Mobile Brain/Body Imaging (MoBI) was used to record electroencephalographic (EEG) activity, three-dimensional (3D) gait kinematics and behavioral responses in the Go/NoGo task, during sitting or walking on a treadmill, in 34 young adults and 37 older adults. Increased response accuracy during walking, independent of age, was found to correlate with slower responses to stimuli (r = 0.44) and with walking-related EEG amplitude modulations over frontocentral regions (r = 0.47) during the sensory gating (N1) and conflict monitoring (N2) stages of inhibition, and over left-lateralized prefrontal regions (r = 0.47) during the stage of inhibitory control implementation (P3). These neural activity changes are related to the cognitive component of inhibition, and they were interpreted as signatures of behavioral improvement during walking. On the other hand, aging, independent of response accuracy during walking, was found to correlate with slower treadmill walking speeds (r = -0.68) and attenuation in walking-related EEG amplitude modulations over left-dominant frontal (r = -0.44) and parietooccipital regions (r = 0.48) during the N2 stage, and over centroparietal regions (r = 0.48) during the P3 stage. These neural activity changes are related to the motor component of inhibition, and they were interpreted as signatures of aging. Older adults whose response accuracy ‘paradoxically’ improved during walking manifested neural signatures of both behavioral improvement and aging, suggesting that their flexibility in reallocating neural resources while walking might be maintained for the cognitive but not for the motor inhibitory component. These distinct neural signatures of aging and behavior can potentially be used to identify ‘super-agers’, or individuals at risk for cognitive decline due to aging or neurodegenerative disease.

Evaluation of Sit-to-Stand Movement in Older Adults with Locomotive Syndrome Using the Nintendo Wii Balance Board.

Standing up from a chair is a mechanically demanding daily motion, and its biomechanics represent motor performance. In older adults with locomotive syndrome (LS), sit-to-stand (STS) movement with adequate postural control is essential to prevent falls. This study evaluated the characteristics of dynamic balance during STS movement on older adults with LS. A total of 116 participants aged ≥65 years were divided into Non-LS, LS stage 1, and LS stage 2 groups using the LS risk test. The participants were instructed to stand on the Nintendo Wii Balance Board as quickly as possible, and the STS movement was quantified using the vertical ground reaction force (VGRF) and center of pressure (CoP). The STS score, which represented dynamic balance, was significantly different among the groups (p < 0.001). The rate of VGRF development was significantly lower in the LS stages 1 and 2 than in the Non-LS group (p < 0.001). On the other hand, the total distance of the CoP path did not differ among the groups (p = 0.211). These findings indicated a reduction of postural control in older adults with LS. The STS score emphasized the importance of balance training to prevent falls in older adults with LS.

Short-term foot warming impacts foot sensitivity and body sway differently in older adults

BackgroundAging is accompanied by loss of foot skin sensitivity and reduced postural control. Increasing foot temperature can improve both skin sensitivity and postural control in adults. However, it remains unclear whether similar effects can be observed in older adults. Research questionCan foot warming improve postural control in older adults, similar to observations in younger adults? MethodsTwo foot warming protocols were conducted in 18 older adults (14 women, 4 men) to increase foot temperature by using infrared radiation to (1) warm the plantar aspect and (2) the skin of the entire foot and ankle area. We assessed the foot skin sensitivity before and after warming, considering tactile stimulation and center of pressure (CoP) displacement during 30-s standing with eyes open and closed. Results and significanceBoth foot warming protocols led to similar increases in skin temperature (∼6 °C) compared to the basal condition, but only warming the entire foot and ankle area increased foot sensitivity for the different regions assessed. No main effects or interactions were found for CoP variables in response to the two warming protocols. The short-term effects identified after warming the entire foot and ankle region suggest that this might be a strategy to improve skin sensitivity in older adults as observed in younger adults, but this was not the case for CoP. Future research should clarify whether the magnitude and long-lasting effects of warming could be determinant of CoP results.

State-dependent interhemispheric inhibition reveals individual differences in motor behavior in chronic stroke

ObjectiveTo investigate state-dependent interhemispheric inhibition (IHI) in chronic stroke survivors compared to neurotypical older adult controls, and test whether abnormal IHI modulation was associated with upper extremity motor behavior. MethodsDual-coil transcranial magnetic stimulation (TMS) measured IHI bi-directionally, between non-lesioned and lesioned motor cortex (M1) in two activity states: (1) at rest and (2) during contralateral isometric hand muscle contraction. IHI was tested by delivering a conditioning stimulus 8-msec or 50-msec prior to a test stimulus over contralateral M1. Paretic motor behavior was assessed by clinical measures of impairment, strength, and dexterity, and mirroring activity in the non-paretic hand. ResultsStroke survivors demonstrated reduced IHI at rest, and less IHI modulation (active – rest) compared to controls. Individual differences in IHI modulation were related to motor behavior differences where greater IHI modulation was associated with greater motor impairment and more mirroring. In contrast, there were no relationships between IHI at rest and motor behavior. ConclusionsAbnormal state-dependent interhemispheric circuit activity may be more sensitive to post-stroke motor deficits than when assessed in a single motor state. SignificanceCharacterizing state-dependent changes in neural circuitry may enhance models of stroke recovery and inform rehabilitation interventions.

Cardiovascular Risk Factor Prevalence, Treatment, and Control in US Adults Aged 20 to 44 Years, 2009 to March 2020

Declines in cardiovascular mortality have stagnated in the US over the past decade, in part related to worsening risk factor control in older adults. Little is known about how the prevalence, treatment, and control of cardiovascular risk factors have changed among young adults aged 20 to 44 years. To determine if the prevalence of cardiovascular risk factors (hypertension, diabetes, hyperlipidemia, obesity, and tobacco use), treatment rates, and control changed among adults aged 20 to 44 years from 2009 through March 2020, overall and by sex and race and ethnicity. Serial cross-sectional analysis of adults aged 20 to 44 years in the US participating in the National Health and Nutrition Examination Survey (2009-2010 to 2017-March 2020). National trends in the prevalence of hypertension, diabetes, hyperlipidemia, obesity, and smoking history; treatment rates for hypertension and diabetes; and blood pressure and glycemic control in those receiving treatment. Among 12 924 US adults aged 20 to 44 years (mean age, 31.8 years; 50.6% women), the prevalence of hypertension was 9.3% (95% CI, 8.1%-10.5%) in 2009-2010 and 11.5% (95% CI, 9.6%-13.4%) in 2017-2020. The prevalence of diabetes (from 3.0% [95% CI, 2.2%-3.7%] to 4.1% [95% CI, 3.5%-4.7%]) and obesity (from 32.7% [95% CI, 30.1%-35.3%] to 40.9% [95% CI, 37.5%-44.3%]) increased from 2009-2010 to 2017-2020, while the prevalence of hyperlipidemia decreased (from 40.5% [95% CI, 38.6%-42.3%] to 36.1% [95% CI, 33.5%-38.7%]). Black adults had high rates of hypertension across the study period (2009-2010: 16.2% [95% CI, 14.0%-18.4%]; 2017-2020: 20.1% [95% CI, 16.8%-23.3%]), and significant increases in hypertension were observed among Mexican American adults (from 6.5% [95% CI, 5.0%-8.0%] to 9.5% [95% CI, 7.3%-11.7%]) and other Hispanic adults (from 4.4% [95% CI, 2.1%-6.8%] to 10.5% [95% CI, 6.8%-14.3%]), while Mexican American adults had a significant rise in diabetes (from 4.3% [95% CI, 2.3%-6.2%] to 7.5% [95% CI, 5.4%-9.6%]). The percentage of young adults treated for hypertension who achieved blood pressure control did not significantly change (from 65.0% [95% CI, 55.8%-74.2%] in 2009-2010 to 74.8% [95% CI, 67.5%-82.1%] in 2017-2020], while glycemic control among young adults receiving treatment for diabetes remained suboptimal throughout the study period (2009-2010: 45.5% [95% CI, 27.7%-63.3%]) to 2017-2020: 56.6% [95% CI, 39.2%-73.9%]). In the US, diabetes and obesity increased among young adults from 2009 to March 2020, while hypertension did not change and hyperlipidemia declined. There was variation in trends by race and ethnicity.

Widespread fMRI BOLD Signal Overactivations during Cognitive Control in Older Adults Are Not Matched by Corresponding Increases in fPET Glucose Metabolism.

A common observation in fMRI studies using the BOLD signal is that older adults, compared with young adults, show overactivations, particularly during less demanding tasks. The neuronal underpinnings of such overactivations are not known, but a dominant view is that they are compensatory in nature and involve recruitment of additional neural resources. We scanned 23 young (20-37 years) and 34 older (65-86 years) healthy human adults of both sexes with hybrid positron emission tomography/MRI. The radioligand [18F]fluoro-deoxyglucose was used to assess dynamic changes in glucose metabolism as a marker of task-dependent synaptic activity, along with simultaneous fMRI BOLD imaging. Participants performed two verbal working memory (WM) tasks: one involving maintenance (easy) and one requiring manipulation (difficult) of information in WM. Converging activations to the WM tasks versus rest were observed for both imaging modalities and age groups in attentional, control, and sensorimotor networks. Upregulation of activity to WM-demand, comparing the more difficult to the easier task, also converged between both modalities and age groups. For regions in which older adults showed task-dependent BOLD overactivations compared with the young adults, no corresponding increases in glucose metabolism were found. To conclude, findings from the current study show that task-induced changes in the BOLD signal and synaptic activity as measured by glucose metabolism generally converge, but overactivations observed with fMRI in older adults are not coupled with increased synaptic activity, which suggests that these overactivations are not neuronal in origin.SIGNIFICANCE STATEMENT Findings of increased fMRI activations in older compared with younger adults have been suggested to reflect increased use of neuronal resources to cope with reduced brain function. The physiological underpinnings of such compensatory processes are poorly understood, however, and rest on the assumption that vascular signals accurately reflect neuronal activity. Comparing fMRI and simultaneously acquired functional positron emission tomography as an alternative index of synaptic activity, we show that age-related overactivations do not appear to be neuronal in origin. This result is important because mechanisms underlying compensatory processes in aging are potential targets for interventions aiming to prevent age-related cognitive decline.

Remote cognitive behavioral therapy for older adults with anxiety symptoms: A systematic review and meta-analysis

Introduction In-person cognitive behavioral therapy (CBT) can reduce self-reported anxiety in older adults. However, studies are limited for remote CBT. We assessed the effectiveness of remote CBT in mitigating self-reported anxiety in older adults. Methods We conducted a systematic review and meta-analysis based on a literature search of PubMed, Embase, PsycInfo, and Cochrane databases up to March 31, 2021, for randomized controlled clinical trials comparing the effectiveness of remote CBT versus non-CBT controls on mitigating self-reported anxiety in older adults. We calculated within-group pre-to-post-treatment standardized mean difference using Cohen's d, obtained the difference between a remote CBT group and a non-CBT control group as our effect size for cross-study comparison, and conducted a random-effects meta-analysis. Changes in scores on self-reported anxiety symptoms (Generalized Anxiety Disorder-7 item Scale, Penn State Worry Questionnaire, or Penn State Worry Questionnaire – Abbreviated), and self-reported depressive symptoms (Patient Health Questionnaire-9 item Scale or Beck Depression Inventory) were primary and secondary outcomes, respectively. Results Six eligible studies, containing 633 participants with a pooled mean age of 66.6 years, were included in the systematic review and meta-analysis. There was a significant mitigating effect of intervention on self-reported anxiety, favoring remote CBT over non-CBT controls (between-group effect size: −0.63; 95% CI: −0.99 to −0.28). We also found a significant mitigating effect of intervention on self-reported depressive symptoms (between-group effect size: −0.74; 95% CI: −1.24 to −0.25). Discussion Remote CBT is more effective in reducing self-reported anxiety and depressive symptoms than non-CBT control in older adults.

Association of cognitive impairment and asthma control in older adults

Cognitive impairment (CI) is prevalent in older patients with asthma. The purpose of this study was to identify if CI was associated with poorer asthma control. Higher systemic inflammation, in particular non-T2, has been associated with CI. We therefore also investigated whether there was a relationship between CI, asthma control, and patterns of cytokine inflammation.

The Effects of Speech Task on Lexical Stress in Parkinson's Disease.

Hypokinetic dysarthria associated with Parkinson's disease (PD) is characterized by dysprosody, yet the literature is mixed with respect to how dysprosody affects the ability to mark lexical stress, possibly due to differences in speech tasks used to assess lexical stress. The purpose of this study was to compare how people with and without PD modulate acoustic dimensions of lexical stress-fundamental frequency, intensity, and duration-to mark lexical stress across three different speech tasks. Twelve individuals with mild-to-moderate idiopathic PD and 12 age- and sex-matched older adult controls completed three speech tasks: picture description, word production in isolation, and word production in lists. Outcome measures were the fundamental frequency, intensity, and duration of the vocalic segments of two trochees (initial stress) and two iambs (final stress) spoken in all three tasks. There were very few group differences. Both groups marked trochees by modulating intensity and fundamental frequency and iambs by modulating duration. Task had a significant impact on the stress patterns used by both groups. Stress patterns were most differentiated in words produced in isolation and least differentiated in lists of words. People with PD did not demonstrate impairments in the production of lexical stress, suggesting that dysprosody associated with PD does not impact all types of prosody in the same way. However, there were reduced distinctions in stress marking that were more apparent in trochees than iambs. In addition, the task used to assess prosody has a significant effect on all acoustic measures. Future research should focus on the use of connected speech tasks to obtain more generalizable measures of prosody in PD.

Low-Molecular Collagen Peptide Supplementation and Body Fat Mass in Adults Aged ≥ 50 Years: A Randomized, Double-Blind, Placebo-Controlled Trial.

A randomized, double-blind, placebo-controlled trial was conducted to confirm whether collagen peptide supplementation for 12 week has a beneficial effect on body fat control in older adults at a daily physical activity level. Participants were assigned to either the collagen group (15 g/day of collagen peptide) or the placebo group (placebo drink). Body composition was measured by bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DEXA). In total, 74 participants (collagen group, n = 37; placebo group, n = 37) were included in the final analysis. The collagen group showed a significant reduction in total body fat mass compared with the placebo group, as evidenced by both BIA (p = 0.021) and DEXA (p = 0.041) measurements. Body fat mass and percent body fat of the whole body and trunk reduced at 12 weeks compared with baseline only in the collagen group (whole body: body fat mass, p = 0.002; percent body fat, p = 0.002; trunk: body fat mass, p = 0.001; percent body fat, p = 0.000). Total fat mass change (%) (collagen group, -0.49 ± 3.39; placebo group, 2.23 ± 4.20) showed a significant difference between the two groups (p = 0.041). Physical activity, dietary intake, and biochemical parameters showed no significant difference between the groups. The results confirmed that collagen peptide supplementation had a beneficial effect on body fat reduction in older adults aged ≥ 50 years with daily physical activity level. Thus, collagen peptide supplementation has a positive effect on age-related changes.

Supplemental Material for Dissociating Proactive and Reactive Control in Older Adults

Supplemental Material for Dissociating Proactive and Reactive Control in Older Adults

Is there a link between heart rate variability and cognitive decline? A cross-sectional study on patients with mild cognitive impairment and cognitively healthy controls.

Given that, up to date, there is no effective strategy to treat dementia, a timely start of interventions in a prodromal stage such as mild cognitive impairment (MCI) is considered an important option to lower the overall societal burden. Although autonomic functions have been related to cognitive performance, both aspects have rarely been studied simultaneously in MCI. The aim of the present study was to investigate cardiac autonomic control in older adults with and without MCI. Cardiac autonomic control was assessed by means of heart rate variability (HRV) at resting state and during cognitive tasks in 22 older adults with MCI and 29 healthy controls (HCs). Resting HRV measurement was performed for 5 minutes during a sitting position. Afterwards, participants performed three PC-based tasks to probe performance in executive functions and language abilities (i.e., Stroop, N-back, and a verbal fluency task). Participants with MCI showed a significant reduction of HRV in the frequency-domain (high frequency power) and nonlinear indices (SD2, D2, and DFA1) during resting state compared to HCs. Older individuals with MCI exhibited decreases in RMSSD and increases in DFA1 from resting state to Stroop and N-back tasks, reflecting strong vagal withdrawal, while this parameter remained stable in HCs. The results support the presence of autonomic dysfunction at the early stage of cognitive impairment. Heart rate variability could help in the prediction of cognitive decline as a noninvasive biomarker or as a tool to monitor the effectiveness of therapy and prevention of neurodegenerative diseases.

Short-term removal of exercise impairs glycemic control in older adults: A randomized trial.

Postprandial glycemia (PPG) predicts cardiovascular disease, and short-term physical inactivity increases PPG in young, active adults. Whether this occurs in older, active adults who may be more prone to bouts of inactivity is unknown. This study determined if postprandial interstitial glucose (PPIG) was impaired in active older adults following the removal of exercise for 3 days (NOEX) compared to active young adults. In this randomized, crossover study, 11 older (69.1 ± 1.9 years) and 9 young (32.8 ± 1.8 years) habitually active (≥90 min/week of exercise) adults completed 3-days of NOEX and 3-days of normal habitual exercise (EX), separated by ≥1week. Diet was standardized across phases. Glycemic control (3-day average) was assessed via continuous glucose monitoring during both phases. Significant main effects of age and phase were detected (p < 0.05), but no interaction was found for steps/day (p > 0.05) (old EX: 6283 ± 607, old NOEX: 2380 ± 382 and young EX: 8798 ± 623, young NOEX: 4075 ± 516 steps/day). Significant main effects of age (p=0.002) and time (p < 0.001) existed for 1-h PPIG, but no effect of phase or interactions was found (p > 0.05). Significant main effects (p < 0.05) of age (old: 114 ± 1mg/dl, young: 106 ± 1mg/dl), phase (NOEX: 112 ± 1mg/dl, EX: 108 ± 1mg/dl), and time (0min: 100 ± 2, 30 min: 118 ± 2, 60 min: 116 ± 2, 90 min: 111 ± 2, 120 min: 108 ± 2mg/dl) in 2-h PPIG were detected, but no interaction was found (p > 0.05). However, only significant main effects of phase (NOEX: 14 ± 1 and EX:12 ± 1, p > 0.05) were found for 24-h blood glucose standard deviation. Older adults appear to have impaired glycemic control compared to young adults and exercise removal impairs glycemic control in both populations. Yet, the impairment in glycemic control with exercise removal is not different between old and young adults.

Effects of instability resistance training on static postural control of cognitively impaired older adults

BACKGROUND: Mounting evidence has demonstrated functional and cognitive-related benefits after Instability Resistance Training (IRT) in individuals, healthy as wellas patients presenting with neurological disorders. However, whether IRT may play a significant role in the postural control of older adults has not been established. OBJECTIVE: To evaluate the effects of 12- weeks of IRT on static postural control of older adults with subjective cognitive impairment. METHODS: In this randomized controlled trial, a total of 67 participants (aged 65 years and older) were randomly assigned to either 12 weeks of IRT (n= 22), traditional resistance training (RT) (n= 23), or a health education control group (CON) (n= 22). Static postural control was assessed using a force platform that recorded the displacement amplitude of the center of pressure (CoP) in the anteroposterior (AP) and mediolateral (ML) directions in bipedal support (30 seconds) with eyes open and closed. RESULTS: All groups increased AP displacement in the conditions of eyes open and closed. During the eyes-closed condition, only the IRT group increased the ML displacement. No between-group differences were detected in any postural control (p&gt; 0.05). CONCLUSIONS: 12 weeks of IRT does not improve the static postural control in older adults with cognitive impairment.

Postural instructions affect postural sway in young adults

BackgroundInstructions to exert effort to correct one’s posture are ubiquitous, but previous work indicates that effort-based postural instructions can impair balance control in older adults with and without neurodegenerative disease. Although less-studied, young adults are at high risk of injurious falls. Research questionHow do different postural instructions influence static balance in young adults? MethodsSingle-session, counterbalanced, within-subjects design. Twenty young adults briefly practiced three different ways of thinking about their posture, then attempted to employ each way of thinking while standing on springy foam for 30 s with eyes open. Relax instructions were used as a baseline between experimental conditions. Effort-based instructions emulated popular concepts of posture correction using muscular exertion. Light instructions aimed at encouraging length and width while reducing excess tension. Postural sway was assessed with an inertial sensor at the low back. ResultsEffort-based postural instructions increased path length and jerk of postural sway during quiet stance, relative to Light and Relaxed instructions. SignificanceThese results are consistent with previous work in older adults indicating that thinking of upright posture as inherently effortful impairs balance. Therefore, the common practice of instructing young adults to use effortful posture may impair their balance performance.