Association between Hypometabolism in the Supplementary Motor Area and Fear of Falling in Older Adults.
ABSTRACT: Background: A better understanding of the neural mechanisms that underlie the development of fear of falling (FoF) in seniors may help to detect potential treatable factors and reduce future falls. We therefore investigate the neural correlates of FoF in older adults using 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET). Methods: This cohort study included 117 community-dwelling older adults. At baseline, participants were assessed for FoF, psychiatric symptoms, walking speed, global cognition and cerebral glucose metabolism with FDG-PET. The incidence of FoF in the participants who did not report FoF (N-FoF) at baseline was again ascertained 2 years later. FDG uptake was compared between the FoF and non-FoF groups. Logistic regression analyses to examine the predictors of newly developed FoF (D-FoF) using normalized regional FDG uptake were then performed. Results: At baseline, 50.4% (n = 59) of participants had FoF. The FoF group had significantly decreased glucose metabolism in the left superior frontal gyrus (supplementary motor area, SMA; BA6) compared to the non-FoF group. After 2 years, 19 out of the 58 participants in the non-FoF group developed FoF. Logistic regression analysis revealed that decreased cerebral glucose metabolism in the left SMA at the baseline was a significant predictor of the future development of FoF, independently of psychiatric symptoms and walking speed. Conclusion: In healthy older adults, hypometabolism in the left SMA, which is involved in motor planning and motor coordination, contributes to the development of FoF. Our result might help elucidate underlying mechanism of the association between deficits in motor control and FoF.
Project description:OBJECTIVE:We investigated type 2 diabetes mellitus (T2DM) as a risk factor for brain atrophy and glucose hypometabolism in older adults with or at risk of cognitive impairment. METHODS:Participants with the T2DM were identified from the Alzheimer's Disease Neuroimaging Initiative (ADNI-1/GO/2 cohorts). Analysis of covariance models were used to compare participants with and without T2DM, controlling for potential confounding factors. RESULTS:Whole brain volume and whole brain [(18)F]-fluorodeoxyglucose (FDG) uptake were significantly different as a function of T2DM status, independent of baseline clinical diagnosis. On post hoc analysis, a lower whole brain volume was seen in participants with both mild cognitive impairment (MCI) and T2DM (n = 76) compared with participants who had MCI but not T2DM (n = 747; p = 0.009). Similarly, mean FDG uptake in gray matter and white matter was lower in participants with both MCI and T2DM (n = 72) than in participants with MCI without T2DM (n = 719; p = 0.04). Subsequent regional analysis revealed that the decreased FDG uptake in participants with both MCI and T2DM was mainly manifested in 3 brain regions: frontal lobe, sensory motor cortex, and striatum. CONCLUSIONS:T2DM may accelerate cognition deterioration in patients with MCI by affecting glucose metabolism and brain volume.
Project description:Objective:To explore relationships between the instrumented timed up and go test (iTUG) and the following risk factors for falls: cognitive functioning, fear of falling (FoF), and quality of life (QoL) in people with dementia. Methods:83 community-dwelling older adults with dementia (mean±sd age 78.00±7.96 years; 60.2% male) completed an interview to capture global cognition (Mini-Addenbrooke's Cognitive Evaluation), FoF (Iconographical Falls Efficacy Scale) and QoL (ICEpopCAPability measure for Older people). Participants completed an iTUG whilst wearing an inertial sensor on their trunk. Linear accelerations and rotational velocities demarcated sub-phases of the iTUG. Relationships were explored through correlations and regression modelling. Results:Cognition was related to duration of walking sub-phases and total time to complete iTUG (r=0.25-0.28) suggesting gait speed was related to cognition. FoF was most strongly related to turning velocity (r=0.39-0.44), but also to sit-to-stand, gait sub-phases and total time to complete iTUG. Sub-phases explained 27% of the variance in FoF. There were no correlations between iTUG and QoL. Conclusions:Cognition and FoF were related to time to complete walking sub-phases but FoF was more closely related to turning velocity and standing acceleration. iTUG may offer unique insights into motor behaviour in people with dementia.
Project description:OBJECTIVES:To determine the prevalence of falls, fear of falling (FoF), and activity limitation due to FoF in a nationally representative study of older adults with self-reported vision impairment (VI). DESIGN:Cross-sectional analysis of panel survey data. SETTING:National Health and Aging Trends Study, a nationally representative survey administered annually from 2011 to 2016 to U.S. Medicare beneficiaries aged 65 and older. PARTICIPANTS:Respondents (N=11,558) who contributed 36,229 participant observations. MEASUREMENTS:We performed logistic regression to calculate the unadjusted and adjusted prevalence of self-reported history of more than 1 fall in the past year, any fall in the past month, FoF, and activity limitation due to FoF in participants with and without self-reported VI. RESULTS:The weighted proportion of participants reporting VI was 8.6% (95% confidence interval (CI)=8.0-9.2%). The unadjusted prevalence of more than 1 fall in the past year was 27.6% (95% CI=25.5-29.7%) in participants with self-reported VI and 13.2% (95% CI=12.7-13.7%) in those without self-reported VI. In respondents with self-reported VI, the prevalence of FoF was 48.3% (95% CI=46.1-50.6%) and of FoF limiting activity was 50.8% (95%CI 47.3-54.2%), and in those without self-reported VI, the prevalence of FoF was 26.7% (95% CI=25.9-27.5%) and of FoF limiting activity was 33.9% (95% CI=32.4-35.4%). The prevalence of all fall and fall-related outcomes remained significantly higher among those with self-reported VI after adjusting for sociodemographics and potential confounders. CONCLUSION:The prevalence of falls, FoF, and activity limitation due to FoF is high in older adults with self-reported VI. This is the first study to provide nationally representative data on the prevalence of fall-related outcomes in older Americans with self-reported VI. These findings demonstrate the need to treat avoidable VI and to develop interventions to prevent falls and fall-related outcomes in this population. J Am Geriatr Soc 67:239-245, 2019.
Project description:<h4>Background</h4>fear of falling (FOF) is a major health concern among community-dwelling older adults that could restrict mobility.<h4>Objective</h4>to examine the association of FOF with life-space mobility (i.e. the spatial area a person moves through in daily life) of community-dwelling older adults from five diverse sites.<h4>Methods</h4>in total, 1,841 older adults (65-74 years) were recruited from Kingston, Canada; Saint-Hyacinthe, Canada; Tirana, Albania; Manizales, Colombia and Natal, Brazil. FOF was assessed using the Fall Efficacy Scale-International (FES-I total score), and the life space was quantified using the Life-Space Assessment (LSA), a scale that runs from 0 (minimum life space) to 120 (maximum life space).<h4>Results</h4>the overall average LSA total score was 68.7 (SD: 21.2). Multiple-linear regression analysis demonstrated a significant relationship of FOF with life-space mobility, even after adjusting for functional, clinical and sociodemographic confounders (B = -0.15, 95% confidence interval (CI) -0.26 to -0.04). The FOF × site interaction term was significant with a stronger linear relationship found in the Canadian sites and Tirana compared with the South American sites. After adjusting for all confounders, the association between FOF with LSA remained significant at Kingston (B = -0.32, 95% CI -0.62 to -0.01), Saint-Hyacinthe (B = -0.81, 95% CI -1.31 to -0.32) and Tirana (B = -0.57, 95% CI -0.89 to -0.24).<h4>Conclusion</h4>FOF is an important psychological factor that is associated with reduction in life space of older adults in different social and cultural contexts, and the strength of this association is site specific. Addressing FOF among older adults would help improve their mobility in local communities, which in turn would improve social participation and health-related quality of life.
Project description:Neural inefficiency is inferred when higher brain activations are associated with similar or worse performance. Improved neural efficiency is achieved when task-related brain activations are reduced after practice. No information is available on the effect of fear-of-falling (FOF) on brain activation during walking. We hypothesized that the presence of FOF would be associated with neural inefficiency and with a delay in improving neural efficiency during dual-task walking. Task conditions included single-task walk (STW), Alpha (cognitive interference), and dual-task walk (DTW). Functional near-infrared spectroscopy (fNIRS)-derived HbO2 in the prefrontal cortex (PFC) was used to quantify task-related changes in brain activation. Practice included three repeated counterbalanced trials for each task. Participants with FOF (n?=?19; mean age =?79.84?±?6.01 years; %female =?68.42) and without FOF (n?=?56; mean age =?76.73?±?6.39 years; %female =?44.64) were included. The presence of FOF was associated with slower stride velocity (estimate =?-?12.354; p = 0.0154) and with greater increases in PFC HbO2 from STW to DTW (estimate =?0.303, p?=?0.0009) and from Alpha to DTW (estimate =?0.387, p?<?0.0001). Compared to controls, participants reporting FOF demonstrated an attenuated decline in PFC HbO2 from the first to the second DTW trials (estimate =?0.264; p?=?0.0173). In contrast, compared to controls, participants with FOF demonstrated greater decline in Alpha PFC HbO2 from trial 1 to trial 2 (estimate =?-?0.419, p?<?0.0001) and from trial 1 to 3 (estimate =?-?0.281, p?=?0.0006). The change in PFC HbO2 over repeated STW trials was not significant and was not moderated by FOF status. The presence of FOF was associated with higher and inefficient PFC activation during DTW in older adults.
Project description:BACKGROUND:We determine the best combination of factors for predicting the risk of developing fear of falling (FOF) in older people via Classification Regression Tree (CaRT) analysis. METHODS:Community-dwelling older adults living in Canada, Albania, Brazil, and Colombia were from International Mobility in Aging Study (IMIAS). In 2014, 1,725 participants (aged 65-74) were assessed. With a retention rate of 81%, in 2016, 1,409 individuals were reassessed. Risk factors for FOF were entered into the CaRT: age, sex, education, self-rated health, comorbidity, medication, visual impairment, frailty, cognitive deficit, depression, fall history, Short Physical Performance Battery (SPPB), walking aid use, and mobility disability measured by the Nagi questionnaire. RESULTS:The classification tree included 12 end groups representing differential risks of FOF with a minimum of two and a maximum of five predictors. The first split in the tree involved impaired physical function (SPPB scores). Respondents with less than 8 in SPPB score and mobility disability had 82% risk of developing FOF at the end of 2-year follow-up. Between 23.2% and 82.3% of the risk of developing FOF in 2 years of follow-up were explained by only five variables: age, sex, self-rated health, functional impairment measured by SPPB, and mobility disability. In those with no functional impairment or mobility disability, levels of education, sex, and self-rated health were important predictors of FOF in the future. CONCLUSION:This classification tree included different groups based on specific combinations of a maximum of five easily measurable predictors with emphasis on impaired physical functioning risk factors for developing FOF.
Project description:Navigated transcranial magnetic stimulation (nTMS) over the supplementary motor area (SMA) may impact fine motor skills. This study evaluates different nTMS parameters in their capacity to affect fine motor performance on the way to develop an SMA mapping protocol. Twenty healthy volunteers performed a variety of fine motor tests during baseline and nTMS to the SMA using 5?Hz, 10?Hz, and theta-burst stimulation (TBS). Effects on performance were measured by test completion times (TCTs), standard deviation of inter-tap interval (SDIT), and visible coordination problems (VCPs). The predominant stimulation effect was slowing of TCTs, i.e. a slowdown of test performances during stimulation. Furthermore, participants exhibited VCPs like accidental use of contralateral limbs or inability to coordinate movements. More instances of significant differences between baseline and stimulation occurred during stimulation of the right hemisphere compared to left-hemispheric stimulation. In conclusion, nTMS to the SMA could enable new approaches in neuroscience and enable structured mapping approaches. Specifically, this study supports interhemispheric differences in motor control as right-hemispheric stimulation resulted in clearer impairments. The application of our nTMS-based setup to assess the function of the SMA should be applied in patients with changed anatomo-functional representations as the next step, e.g. among patients with eloquent brain tumors.
Project description:IMPORTANCE:Converging evidence suggests that Alzheimer disease (AD) involves insulin signaling impairment. Patients with AD and individuals at risk for AD show reduced glucose metabolism, as indexed by fludeoxyglucose F 18-labeled positron emission tomography (FDG-PET). OBJECTIVES:To determine whether insulin resistance predicts AD-like global and regional glucose metabolism deficits in late middle-aged participants at risk for AD and to examine whether insulin resistance-predicted variation in regional glucose metabolism is associated with worse cognitive performance. DESIGN, SETTING, AND PARTICIPANTS:This population-based, cross-sectional study included 150 cognitively normal, late middle-aged (mean [SD] age, 60.7 [5.8] years) adults from the Wisconsin Registry for Alzheimer's Prevention (WRAP) study, a general community sample enriched for AD parental history. Participants underwent cognitive testing, fasting blood draw, and FDG-PET at baseline. We used the homeostatic model assessment of peripheral insulin resistance (HOMA-IR). Regression analysis tested the statistical effect of HOMA-IR on global glucose metabolism. We used a voxelwise analysis to determine whether HOMA-IR predicted regional glucose metabolism. Finally, predicted variation in regional glucose metabolism was regressed against cognitive factors. Covariates included age, sex, body mass index, apolipoprotein E ?4 genotype, AD parental history status, and a reference region used to normalize regional uptake. MAIN OUTCOMES AND MEASURES:Regional glucose uptake determined using FDG-PET and neuropsychological factors. RESULTS:Higher HOMA-IR was associated with lower global glucose metabolism (??=?-0.29; P?<?.01) and lower regional glucose metabolism across large portions of the frontal, lateral parietal, lateral temporal, and medial temporal lobes (P?<?.05, familywise error corrected). The association was especially robust in the left medial temporal lobe (R2?=?0.178). Lower glucose metabolism in the left medial temporal lobe predicted by HOMA-IR was significantly related to worse performance on the immediate memory (??=?0.317; t148?=?4.08; P?<?.001) and delayed memory (??=?0.305; t148?=?3.895; P?<?.001) factor scores. CONCLUSIONS AND RELEVANCE:Our results show that insulin resistance, a prevalent and increasingly common condition in developed countries, is associated with significantly lower regional cerebral glucose metabolism, which in turn may predict worse memory performance. Midlife may be a critical period for initiating treatments to lower peripheral insulin resistance to maintain neural metabolism and cognitive function.
Project description:Abstract Fear of falling (FoF) and reduction in physical functioning is common among older people. The objective of this study was to evaluate the effectiveness of three intervention programs to decrease fear of falling and improve physical functioning among older people with FoF and functional limitation. A randomized controlled trial was conducted (identifier NCT03211429). A hundred and twenty-five individuals were randomized to one of three interventions: Tai Chi (TC), cognitive behavioral therapy (CBT), or a control exercise group (PC). The primary outcomes were fear of falling and functionality. All postural interventions were performed weekly for 8 weeks. Compared to baseline, fear of falls significantly reduced in all groups (effect sizes d Cohen) TC 0.37, CBT 0.80, and PC 0.71). Similarly, compared to baseline, physical functioning improved in all groups (effect sizes: TC -0.49, CBT -0.49, and PC -0.83). In summary, the three intervention programs are effective on FoF and functionality, but, CBT is most effective on FoF and CP most effective for physical functioning.
Project description:This study examined the influence of motor symptom asymmetry in Parkinson's disease (PD) on Grooved Pegboard (GP) performance in right-handed participants. The Unified Parkinson's Disease Rating Scale was used to assess motor symptoms and separate participants with PD into two groups (right-arm affected, left-arm affected) for comparison with a group of healthy older adults. Participants completed the place and replace GP tasks two times with both hands. Laterality quotients were computed to quantify performance differences between the two hands. Comparisons among the three groups indicated that when the nonpreferred hand is affected by PD motor symptoms, superior preferred hand performance (as seen in healthy older adults) is further exaggerated in tasks that require precision (i.e., place task). Regardless of the task, when the preferred hand is affected, there is an evident shift to superior left-hand performance, which may inevitably manifest as a switch in hand preference. Results add to the discussion of the relationship between handedness and motor symptom asymmetry in PD.