Brad Manor

Objectives: To determine the effects of tai chi training on functional performance and walking with and without the addition of the performance of a cognitive task, in older adults living in supportive housing facilities. Design: Secondary data analysis comparing a single‐blind, randomized controlled trial of tai chi training with an attention‐matched educational control intervention with crossover to tai chi. Setting: Two supportive housing facilities. Participants: Sixty‐six men and women living in supportive housing facilities entered the study, and 57 aged 87 ± 7 completed all study procedures. Intervention: Interventions consisted of two 1‐hour‐long instructor‐led group sessions per week for 12 weeks. Tai chi training consisted of movements based upon the Yang‐style short form. Educational sessions consisted of lectures and discussions of age‐related health topics. Measurements: Subjects were tested for physical function (Short Physical Performance Battery, SPPB ), balance (Berg Balance Scale, BBS ), mobility (timed up‐and‐go, TUG ), and walking speed under normal and cognitive dual‐task conditions. Results: The tai chi group exhibited greater improvement in SPPB scores (baseline 8.1 ± 2.9, follow‐up 9.0 ± 2.6) than controls (baseline 8.2 ± 2.6, follow‐up 8.2 ± 2.6) ( P = .005). Tai chi also increased normal and dual‐task walking speed ( P < .001) yet did not affect BBS ( P = .02) or TUG ( P = .02) after accounting for multiple comparisons. The dual‐task cost (percentage change) to walking speed was unaffected. After the crossover tai chi intervention, the control group improved performance in the SPPB , BBS , and TUG , and increased walking speed under normal and dual‐task conditions ( P = .008). Conclusion: Tai chi training may be a safe and effective therapy to help improve physical function and dual‐task walking in very old adults living in supportive housing facilities.

Objective: Brain damage within the right middle cerebral artery (MCA) territory is particularly disruptive to mediolateral postural stabilization. The objective of this cross-sectional study was to test the hypothesis that chronic right MCA infarcts (as compared to left) are associated with slower and more bilaterally asymmetrical gait. We further hypothesized that in those with chronic right MCA infarct, locomotor performance is more dependent on gray matter (GM) volumes within noninfarcted regions of the brain that are involved in motor control yet lie outside of the MCA territory. Methods: Gait speed was assessed in 19 subjects with right MCA infarct, 20 with left MCA infarct, and 108 controls. Bilateral plantar pressure and temporal symmetry ratios were calculated in a subset of the cohort. GM volumes within 5 regions outside of the MCA territory (superior parietal lobe, precuneus, caudate, putamen, and cerebellum) were quantified from anatomic MRIs. Results: Right and left infarct groups had similar poststroke duration (7.6 ± 6.0 years), infarct size, and functional independence. The right infarct group demonstrated slower gait speed and greater asymmetry compared to the left infarct group and controls (p < 0.05). In the right infarct group only, those with larger GM volumes within the cerebellum (r² = 0.32, p = 0.02) and caudate (r² = 0.56, p < 0.001) exhibited faster gait speed. Conclusion: Individuals with chronic lesions within the right MCA territory, as compared to the left MCA territory, exhibit slower, more asymmetrical gait. For these individuals, larger GM volumes within regions outside of the infarcted vascular territory may help preserve locomotor control.

Tai Chi training enhances physical function and may reduce falls in older adults with and without balance disorders, yet its effect on postural control as quantified by the magnitude or speed of center-of-pressure (COP) excursions beneath the feet is less clear. We hypothesized that COP metrics derived from complex systems theory may better capture the multi-component stimulus that Tai Chi has on the postural control system, as compared with traditional COP measures.

Aging alters brain structure and function and diabetes mellitus (DM) may accelerate this process. This study investigated the effects of type 2 DM on individual brain aging as well as the relationships between individual brain aging, risk factors and functional measures. To differentiate a pattern of brain atrophy that deviates from normal brain aging, we used the novel BrainAGE approach, which determines the complex multidimensional aging pattern within the whole brain by applying established kernel regression methods to anatomical brain MRIs. The “Brain Age Gap Estimation” (i.e., BrainAGE score) was then calculated as the difference between chronological age and estimated brain age. 185 subjects (98 with type 2 DM) completed an MRI at 3T, laboratory and clinical assessments. Twenty-five subjects (12 with type 2 DM) also completed a follow-up visit after 3.8 ± 1.5 years. The estimated brain age of DM subjects was 4.6 ± 7.2 years greater than their chronological age (p = 0.0001), whereas within the control group, estimated brain age was similar to chronological age. As compared to baseline, the average BrainAGE scores of DM subjects increased by 0.2 years per follow-up year (p = 0.034), whereas the BrainAGE scores of controls did not change between baseline and follow-up. At baseline, across all subjects, higher BrainAGE scores were associated with greater smoking and alcohol consumption, higher tumor necrosis factor (TNFα) levels, lower verbal fluency scores and more severe depression. Within the DM group, higher BrainAGE scores were associated with longer diabetes duration (r = 0.31, p = 0.019) and increased fasting blood glucose levels (r = 0.34, p = 0.025). In conclusion, type 2 DM is independently associated with structural changes in the brain that reflect advanced aging. The BrainAGE approach may thus serve as a clinically relevant biomarker for the detection of abnormal patterns of brain aging associated with type 2 DM.

OBJECTIVE Diabetic peripheral neuropathy (DPN) alters walking. Yet, the compensatory role of central locomotor circuits remains unclear. We hypothesized that walking outcomes would be more closely related to regional gray matter volumes in older adults with DPN as compared with nonneuropathic diabetic patients and nondiabetic control subjects. RESEARCH DESIGN AND METHODS Clinically important outcomes of walking (i.e., speed, stride duration variability, and double support time) were measured in 29 patients with DPN (type 2 diabetes with foot-sole somatosensory impairment), 68 diabetic (DM) patients (type 2 diabetes with intact foot-sole sensation), and 89 control subjects. Global and regional gray matter volumes were calculated from 3 Tesla magnetic resonance imaging. RESULTS DPN subjects walked more slowly (P = 0.005) with greater stride duration variability (P < 0.001) and longer double support (P < 0.001) as compared with DM and control subjects. Diabetes was associated with less cerebellar gray matter volume (P < 0.001), but global gray matter volume was similar between groups. DPN subjects with lower gray matter volume globally (P < 0.004) and regionally (i.e., cerebellum, right-hemisphere dorsolateral prefrontal cortex, basal ganglia, P < 0.005) walked more slowly with greater stride duration variability and/or longer double support. Each relationship was stronger in DPN than DM subjects. In control subjects, brain volumes did not relate to walking patterns. CONCLUSIONS Strong relationships between brain volumes and walking outcomes were observed in the DPN group and to a lesser extent the DM group, but not in control subjects. Individuals with DPN may be more dependent upon supraspinal elements of the motor control system to regulate several walking outcomes linked to poor health in elderly adults.

Foot sole somatosensory feedback is critical to motor control and declines with aging and disease. To enable study of cortical networks underlying foot sole somatosensation, we developed a pneumatic tactile stimulator capable of producing one degree‐of‐freedom (DOF) oscillations with preset waveform, frequency (≤10 Hz), force magnitude (5–500 N), duty cycle (20–100%), and contacted surface area over which pressures are applied to the foot sole. Image tests (anatomical/functional/field map) of a phantom demonstrated that the device is compatible with 3 T MRI. Gradient‐recalled echo‐planar images of seven healthy young adults using a typical block‐designed 1 Hz sinusoidal stimulation protocol revealed significant activation contralaterally within the primary somatosensory cortex and paracentral gyrus, and bilaterally within the secondary somatosensory cortex. The stimulation system may therefore serve as a research tool to study functional brain networks involved in the perception and modulation of foot sole somatosensation and its relationship to motor control. Magn Reson Med 69:1194–1199, 2013.

The degree of multiscale complexity in human behavioral regulation, such as that required for postural control, appears to decrease with advanced aging or disease. To help delineate causes and functional consequences of complexity loss, we examined the effects of visual and somatosensory impairment on the complexity of postural sway during quiet standing and its relationship to postural adaptation to cognitive dual tasking. Participants of the MOBILIZE Boston Study were classified into mutually exclusive groups: controls [intact vision and foot somatosensation, n = 299, 76 ± 5 (SD) yr old], visual impairment only (n = 81, 77 ± 4 yr old), somatosensory impairment only (inability to perceive 5.07 monofilament on plantar halluxes, n = 48, 80 ± 5 yr old), and combined impairments (n = 25, 80 ± 4 yr old). Postural sway (i.e., center-of-pressure) dynamics were assessed during quiet standing and cognitive dual tasking, and a complexity index was quantified using multiscale entropy analysis. Postural sway speed and area, which did not correlate with complexity, were also computed. During quiet standing, the complexity index (mean ± SD) was highest in controls (9.5 ± 1.2) and successively lower in the visual (9.1 ± 1.1), somatosensory (8.6 ± 1.6), and combined (7.8 ± 1.3) impairment groups (P = 0.001). Dual tasking resulted in increased sway speed and area but reduced complexity (P < 0.01). Lower complexity during quiet standing correlated with greater absolute (R = −0.34, P = 0.002) and percent (R = −0.45, P < 0.001) increases in postural sway speed from quiet standing to dual-tasking conditions. Sensory impairments contributed to decreased postural sway complexity, which reflected reduced adaptive capacity of the postural control system. Relatively low baseline complexity may, therefore, indicate control systems that are more vulnerable to cognitive and other stressors.