Background: Although vibration training has been applied in older adults, it remains unclear if it can reduce falls. Aims: This pilot randomized-controlled trial aimed to test the effects of an 8-week vibration training program on reducing falls among community-dwelling adults. Methods: Forty-eight older adults were randomized to two groups: training and control. The training group received three weekly training sessions over eight weeks while the control group maintained their normal lifestyle over the 8-week period. Immediately before (or baseline), following (post-training), and three months after (retest) the 8-week training course, a group of fall risk factors were assessed for all participants. Each participant was also exposed to an unexpected gait-slip on a treadmill during post-training and retest sessions. Their daily-living fall incidence was collected for 12 months after the baseline test. The slip fall was the primary outcome, prospective all-cause falls were the secondary outcome, and fall risk factors acted as the tertiary ones. Results: The vibration training program significantly reduced the risk of slip-falls and improved all fall risk factors immediately after the training course. The training effect may be carried over for three months. The 8-week training program could also lower the number of falls between the baseline test and retest and reduce the recurrent faller rate across the 12 months after the baseline test. Discussion: This study indicates that vibration training might have some effects on fall-related measures in older adults. Conclusions: An 8-week vibration training program could be effective to reduce falls in older adults. ClinicalTrials.gov registration number: NCT02694666.
Background: This study determined the reliability of topographic motor cortical maps and MEP characteristics in the extensor digitorum communis (EDC) evoked by single-pulse TMS among patients with chronic stroke. Methods: Each of ten patients was studied on three occasions. Measures included location of the EDC hotspot and center of gravity (COG), threshold of activation and average amplitude of the hotspot, number of active sites, map volume, and recruitment curve (RC) slope. Results: Consistent intrahemispheric measurements were obtained for the three TMS mapping sessions for all measured variables. No statistically significant difference was observed between hemispheres for the number of active sites, COG distance or the RC slope. The magnitude and range of COG movement between sessions were similar to those reported previously with this muscle in able-bodied individuals. The average COG movement over three sessions in both hemispheres was 0.90 cm. The average COG movement in the affected hemisphere was 1.13 (± 0.08) cm, and 0.68 (± 0.04) cm) for the less affected hemisphere. However, significant interhemispheric variability was seen for the average MEP amplitude, normalized map volume, and resting motor threshold. Conclusion: The physiologic variability in some TMS measurements of EDC suggest that interpretation of TMS mapping data derived from hemiparetic patients in the chronic stage following stroke should be undertaken cautiously. Irrespective of the muscle, potential causes of variability should be resolved to accurately assess the impact of pharmacological or physical interventions on cortical organization as measured by TMS among patients with stroke.
Objective: Neuroimaging techniques, such as diffusion tensor imaging (DTI) and blood oxygenation level–dependent (BOLD) functional magnetic resonance imaging (fMRI), provide insights into the functional reorganization of the cortical motor system after stroke. This study explores the relationship between upper extremity motor function, white matter integrity, and BOLD response of cortical motor areas.
Methods: Seventeen patients met study inclusion criteria; of these 12 completed DTI assessment of white matter integrity and 9 completed fMRI assessment of motor-related activation. Primary clinical outcome measures were the Wolf Motor Function Test (WMFT) and the upper limb portion of the Fugl-Meyer (FM) motor assessment. Structural integrity of the posterior limb of the internal capsule was assessed by examining the fractional anisotropy (FA) asymmetry in the PLIC. Laterality index of motor cortical areas was measured as the BOLD response in each patient during a finger pinch task. Linear regression analyses were performed to determine whether clinical outcome was associated with structural or functional MRI measures.
Results: There were strong relationships between clinical outcome measures and FA asymmetry (eg, FM score [R2 = .655, P = .001] and WMFT asymmetry score [R2 = .651, P < .002]) but relationships with fMRI measures were weaker.
Conclusion: Clinical motor function is more closely related to the white matter integrity of the internal capsule than to BOLD response of motor areas in patients 3 to 9 months after stroke. Thus, use of DTI to assess white matter integrity in the internal capsule may provide more useful information than fMRI to interpret motor deficits following supratentorial brain injury.
The authors examined serial changes in optical topography in a stroke patient performing a functional task, as well as clinical and physiologic measures while undergoing constraint-induced therapy (CIT). A 73-year-old right hemiparetic patient, who had a subcortical stroke 4 months previously, received 2 weeks of CIT. During the therapy, daily optical topography imaging using near-infrared light was measured serially while the participant performed a functional key-turning task. Clinical outcome measures included the Wolf Motor Function Test (WMFT), Motor Activity Log (MAL), and functional key grip test. Transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) were also used to map cortical areas and hemodynamic brain responses, respectively. Optical topography measurement showed an overall decrease in oxy-hemoglobin concentration in both hemispheres as therapy progressed and the laterality index increased toward the contralateral hemisphere. An increased TMS motor map area was observed in the contralateral cortex following treatment. Posttreatment fMRI showed bilateral primary motor cortex activation, although slightly greater in the contralateral hemisphere, during affected hand movement. Clinical scores revealed marked improvement in functional activities. In one patient who suffered a stroke, 2 weeks of CIT led to improved function and cortical reorganization in the hemisphere contralateral to the affected hand.
Mental imagery can improve motor performance in stroke populations when combined with physical therapy. Valid and reliable instruments to evaluate the imagery ability of stroke survivors are needed to maximize the benefits of mental imagery therapy. The purposes of this study were to: examine and compare the test-retest intra-rate reliability of the Movement Imagery Questionnaire-Revised, Second Edition (MIQ-RS) in stroke survivors and able-bodied controls, examine internal consistency of the visual and kinesthetic items of the MIQ-RS, determine if the MIQ-RS includes both the visual and kinesthetic dimensions of mental imagery, correlate impairment and motor imagery scores, and investigate the criterion validity of the MIQ-RS in stroke survivors by comparing the results to the KVIQ-10. Test-retest analysis indicated good levels of reliability (ICC range: .83–.99) and internal consistency (Cronbach α: .95–.98) of the visual and kinesthetic subscales in both groups. The two-factor structure of the MIQ-RS was supported by factor analysis, with the visual and kinesthetic components accounting for 88.6% and 83.4% of the total variance in the able-bodied and stroke groups, respectively. The MIQ-RS is a valid and reliable instrument in the stroke population examined and able-bodied populations and therefore useful as an outcome measure for motor imagery ability.
OBJECTIVE: Constraint-induced movement therapy (CIMT) has been shown to improve upper extremity voluntary movement and change cortical movement representation after stroke. Direct comparison of the differential degree of cortical reorganization according to chronicity in stroke subjects receiving CIMT has not been performed and was the purpose of this study. We hypothesized that a higher degree of cortical reorganization would occur in the early (less than 9 months post-stroke) compared to the late group (more than 12 months post-stroke).
METHODS: 17 early and 9 late subjects were enrolled. Each subject was evaluated using transcranial magnetic stimulation (TMS) and the Wolf Motor Function Test (WMFT) and received CIMT for 2 weeks.
RESULTS: The early group showed greater improvement in WMFT compared with the late group. TMS motor maps showed persistent enlargement in both groups but the late group trended toward more enlargement. The map shifted posteriorly in the late stroke group. The main limitation was the small number of TMS measures that could be acquired due to high motor thresholds, particularly in the late group.
CONCLUSION: CIMT appears to lead to greater improvement in motor function in the early phase after stroke. Greater cortical reorganization in map size and position occurred in the late group in comparison.
SIGNIFICANCE: The contrast between larger functional gains in the early group vs larger map changes in the late group may indicate that mechanisms of recovery change over the several months following stroke or that map changes are a time-dependent epiphenomenon.
Physical fitness has been long associated with maintenance and improvement of motor performance as we age. In particular, measures of psychomotor speed and motor dexterity tend to be higher in physically fit aging adults as compared to their sedentary counterparts. Using functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS), we explored the patterns of neural activity that may, in part, account for differences between individuals of varying physical fitness levels. In this study, we enrolled both sedentary and physically fit middle age (40–60) and younger (18–30) adults and measured upper extremity motor performance during behavioral testing. In a follow-up session, we employed TMS and fMRI to assess levels of interhemispheric communication during unimanual tasks. Results show that increased physical fitness is associated with better upper extremity motor performance on distal dexterity assessments and increased levels of interhemispheric inhibition in middle age adults. Further, the functional correlates of changes of ipsilateral activity appears to be restricted to the aging process as younger adults of varying fitness levels do not differ in hemispheric patterns of activity or motor performance. We conclude that sedentary aging confers a loss of interhemispheric inhibition that is deleterious to some aspects of motor function, as early as midlife, but these changes can be mediated by chronic engagement in aerobic exercise.
Keywords: aging neuroscience, aging, fMRI, TMS, physical fitness, interhemispheric communication, negative BOLD, dexterity
Background
At 6 months poststroke, most patients cannot incorporate their affected hand into daily activities, which in turn is likely to reduce their perceived quality of life.
Objective
This preliminary study explored change in patient-reported, health-related quality of life associated with robotic-assisted therapy combined with reduced therapist-supervised training.
Design and Setting
A single-blind, multi-site, randomized clinical trial was conducted.
Participants
Seventeen individuals who were 3 to 9 months poststroke participated.
Intervention
Sixty hours of therapist-supervised repetitive task practice (RTP) was compared with 30 hours of RTP combined with 30 hours of robotic-assisted therapy.
Measurements
Participants completed the Stroke Impact Scale (SIS) at baseline, immediately postintervention, and 2 months postintervention. Change in SIS score domains was assessed in a mixed model analysis.
Results
The combined therapy group had a greater increase in rating of mood from preintervention to postintervention, and the RTP-only group had a greater increase in rating of social participation from preintervention to follow-up. Both groups had statistically significant improvement in activities of daily living and instrumental activities of daily living scores from preintervention to postintervention. Both groups reported significant improvement in hand function postintervention and at follow-up, and the magnitude of these changes suggested clinical significance. The combined therapy group had significant improvements in stroke recovery rating postintervention and at follow-up, which appeared clinically significant; this also was true for stroke recovery rating from preintervention to follow-up in the RTP-only group.
Limitations
Outcomes of 30 hours of RTP in the absence of robotic-assisted therapy remain unknown.
Conclusion
Robotic-assisted therapy may be an effective alternative or adjunct to the delivery of intensive task practice interventions to enhance hand function recovery in patients with stroke.
Background
This study determined the reliability of topographic motor cortical maps and MEP characteristics in the extensor digitorum communis (EDC) evoked by single-pulse TMS among patients with chronic stroke.
Methods
Each of ten patients was studied on three occasions. Measures included location of the EDC hotspot and center of gravity (COG), threshold of activation and average amplitude of the hotspot, number of active sites, map volume, and recruitment curve (RC) slope.
Results
Consistent intrahemispheric measurements were obtained for the three TMS mapping sessions for all measured variables. No statistically significant difference was observed between hemispheres for the number of active sites, COG distance or the RC slope. The magnitude and range of COG movement between sessions were similar to those reported previously with this muscle in able-bodied individuals. The average COG movement over three sessions in both hemispheres was 0.90 cm. The average COG movement in the affected hemisphere was 1.13 (± 0.08) cm, and 0.68 (± 0.04) cm) for the less affected hemisphere. However, significant interhemispheric variability was seen for the average MEP amplitude, normalized map volume, and resting motor threshold.
Conclusion
The physiologic variability in some TMS measurements of EDC suggest that interpretation of TMS mapping data derived from hemiparetic patients in the chronic stage following stroke should be undertaken cautiously. Irrespective of the muscle, potential causes of variability should be resolved to accurately assess the impact of pharmacological or physical interventions on cortical organization as measured by TMS among patients with stroke.
Recent studies have shown that during unimanual motor tasks, aging adults show bilateral recruitment of primary motor cortex (M1), while younger adults show a suppression of the ipsilateral motor cortex. Additional work has indicated that increased bilateral M1 recruitment in older adults may be deleterious when performing some motor tasks. However, higher levels of physical fitness are associated with improved dexterity and fitness may mitigate the loss of both inhibitory and excitatory communication in aging adults. The goal of this study was to assess dexterity and interhemispheric motor communication in physically fit and sedentary middle-age (40–60 years) right handed participants using tests of hand deftness and transcranial magnetic stimulation (TMS). To behaviorally assess the influence of interhemispheric communication on motor performance, participants also perform the coin rotation deftness task while maintaining pinch force with the opposite hand (bimanual condition). We correlated these behavioral measures with the ipsilateral silent period using TMS to assess interhemispheric inhibition. Our results show that the middle-aged adults who were physically fit had better dexterity of their right hand (finger tapping and peg-board). When performing the coin rotation task the fit group had no between hand differences, but the sedentary group’s left hand performance was inferior to the their right hand. We found that better dexterity correlated with ipsilateral silent period duration (greater inhibition) thereby supporting the postulate that fitness improves interhemispheric motor communication.