The Influence of Aging on the Functional Connectivity of the Human Basal Ganglia

Although basal ganglia (BG) are involved in the motor disorders of aged people, the effect of aging on the functional interaction of BG is not well-known. This work was aimed at studying the influence of aging on the functional connectivity of the motor circuit of BG (BGmC). Thirty healthy volunteers were studied (young-group 26.4 ± 5.7 years old; aged-group 63.1 ± 5.8 years old) with a procedure planned to prevent the spurious functional connectivity induced by the closed-loop arrangement of the BGmC. BG showed different functional interactions during the inter-task intervals and when subjects did not perform any voluntary task. Aging induced marked changes in the functional connectivity of the BGmC during these inter-task intervals. The finger movements changed the functional connectivity of the BG, these modifications were also different in the aged-group. Taken together, these data show a marked effect of aging on the functional connectivity of the BGmC, and these effects may be at the basis of the motor handicaps of aged people during the execution of motor-tasks and when they are not performing any voluntary motor task.

Low-Frequency rTMS over Contralesional M1 Increases Ipsilesional Cortical Excitability and Motor Function with Decreased Interhemispheric Asymmetry in Subacute Stroke: A Randomized Controlled Study

Objective. To determine the long-term effects of low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) over the contralesional M1 preceding motor task practice on the interhemispheric asymmetry of the cortical excitability and the functional recovery in subacute stroke patients with mild to moderate arm paresis. Methods. Twenty-four subacute stroke patients were randomly allocated to either the experimental or control group. The experimental group underwent rTMS over the contralesional M1 (1 Hz), immediately followed by 30 minutes of motor task practice (10 sessions within 2 weeks). The controls received sham rTMS and the same task practice. Following the 2-week intervention period, the task practice was continued twice weekly for another 10 weeks in both groups. Outcomes were evaluated at baseline (T0), at the end of the 2-week stimulation period (T1), and at 12-week follow-up (T2). Results. The MEP (paretic hand) and interhemispheric asymmetry, Fugl-Meyer motor assessment, Action Research Arm Test, and box and block test scores improved more in the experimental group than controls at T1 ( p < 0.05 ). The beneficial effects were largely maintained at T2. Conclusion. LF-rTMS over the contralesional M1 preceding motor task practice was effective in enhancing the ipsilesional cortical excitability and upper limb function with reducing interhemispheric asymmetry in subacute stroke patients with mild to moderate arm paresis. Significance. Adding LF-rTMS prior to motor task practice may reduce interhemispheric asymmetry of cortical excitabilities and promote upper limb function recovery in subacute stroke with mild to moderate arm paresis.

MOVEMENT ASSESSMENT BATTERY FOR CHILDREN-SECOND EDITION: THEORETICAL ADEQUACY OF A MOTOR ASSESSMENT INSTRUMENT

ABSTRACT Objective: To investigate the adequacy of the theoretical model of the Movement Assessment Battery for Children-Second Edition (MABC-2) instrument. Methods: 582 children, of both sexes, aged between 3 and 5 years and residents in the city of Maringá (state of Paraná, Southern Brazil) participated in the study. Data were collected from May/2014 to June/2015 and analyzed using descriptive and inferential statistics. Results: The evidence obtained from exploratory factor analysis indicated the presence of two factors, which was the option that best fitted the explanatory model. Hence, it was necessary to regroup the motor tasks of the dimensions “Aiming & catching” and “Balance” into only one dimension. It is noteworthy that the “Bicycle trail” motor task did not fit the model, as it presented a low and negative factor load in the analyzed dimensions. In the confirmatory factor analysis, adequate adjustment indices were observed for the tested model, which confirmed the non-classification of the “Bicycle trail” motor task in the original dimension. Conclusions: After removing the “Bicycle trail” motor task, the adjusted two-factor model seems to be the most appropriate to assess the motor performance of children participating in the study.

Dry EEG Measurement of P3 to Evaluate Cognitive Load During Sitting, Standing, and Walking

The impact of cognitive load on individuals with motor impairments is poorly understood. Cognitive load has been studied using subjective assessments, dual-task studies, physiological measures, and clinical metrics, which are specific to the motor task being performed and do not measure brain signals directly. Combining brain imaging with dual-task paradigms provides a quantitative, direct metric of cognitive load that is agnostic to the motor task. To better understand the impact of cognitive load during activities of daily living, we measured brain activity from a dry EEG headset as participants attended to an auditory stimulus paradigm during sitting, standing, and walking. The stimulus paradigm consisted of an auditory oddball task in which they had to report the number of oddball tones that were heard during each task. The P3 event-related potential, which is sensitive to cognitive load, was extracted from EEG signals in each condition. Results showed that P3 was significantly lower during walking compared to sitting (p = .039), indicating that cognitive load was higher during walking compared to the other activities. No significant differences in P3 were found between sitting and standing. Head motion did not have a significant impact on the measurement of cognitive load. These results encourage the use of a dry EEG system to further investigate cognitive load during dynamic activities in individuals with and without motor impairments.

2BALANCE: Test-retest reliability of a cognitive-motor dual-task protocol

PURPOSE: Aside from typical symptoms such as dizziness and vertigo, persons with vestibular disorders often have cognitive and motor problems. These symptoms have been assessed in single-task condition. However, dual-tasks assessing cognitive-motor interference might be an added value as they reflect daily life situations better. Therefore, the 2BALANCE protocol was developed. In the current study, the test-retest reliability of this protocol was assessed. METHODS: The 2BALANCE protocol was performed twice in 20 healthy young adults with an in-between test interval of two weeks. Two motor tasks and five different cognitive tasks were performed in single and dual-task condition. Intraclass correlation coefficients (ICC), the standard error of measurement, and the minimal detectable difference were calculated. RESULTS: All cognitive tasks, with the exception of the mental rotation task, had favorable reliability results (0.26≤ICC≤0.91). The dynamic motor task indicated overall substantial reliability values in all conditions (0.67≤ICC≤0.98). Similar results were found for the static motor task during dual-tasking (0.50≤ICC≤0.92), but were slightly lower in single-task condition (–0.26≤ICC≤0.75). CONCLUSIONS: The 2BALANCE protocol was overall consistent across trials. However, the mental rotation task showed lowest reliability values.

Effect of proprioceptive stimulation using a soft robotic glove on motor activation and brain connectivity in stroke survivors

Objective. Soft-robotic-assisted training may improve motor function during post-stroke recovery, but the underlying physiological changes are not clearly understood. We applied a single-session of intensive proprioceptive stimulation to stroke survivors using a soft robotic glove to delineate its short-term influence on brain functional activity and connectivity. Approach. In this study, we utilized task-based and resting-state functional magnetic resonance imaging (fMRI) to characterize the changes in different brain networks following a soft robotic intervention. Nine stroke patients with hemiplegic upper limb engaged in resting-state and motor-task fMRI. The motor tasks comprised two conditions: active movement of fingers (active task) and glove-assisted active movement using a robotic glove (glove-assisted task), both with visual instruction. Each task was performed using bilateral hands simultaneously or the affected hand only. The same set of experiments was repeated following a 30-minute treatment of continuous passive motion (CPM) using a robotic glove. Main results. On simultaneous bimanual movement, increased activation of supplementary motor area (SMA) and primary motor area (M1) were observed after CPM treatment compared to the pre-treatment condition, both in active and glove-assisted task. However, when performing the tasks solely using the affected hand, the phenomena of increased activity were not observed either in active or glove-assisted task. The comparison of the resting-state fMRI between before and after CPM showed the connectivity of the supramarginal gyrus and SMA was increased in the somatosensory network and salience network. Significance. This study demonstrates how passive motion exercise activates M1 and SMA in the post-stroke brain. The effective proprioceptive motor integration seen in bimanual exercise in contrast to the unilateral affected hand exercise suggests that the unaffected hemisphere might reconfigure connectivity to supplement damaged neural networks in the affected hemisphere. The somatosensory modulation rendered by the intense proprioceptive stimulation would affect the motor learning process in stroke survivors.

Association Between Motor Task Performance and Hippocampal Atrophy Across Cognitively Unimpaired, Amnestic Mild Cognitive Impairment, and Alzheimer’s Disease Individuals

Hippocampal atrophy is a widely used biomarker for Alzheimer’s disease (AD), but the cost, time, and contraindications associated with magnetic resonance imaging (MRI) limit its use. Recent work has shown that a low-cost upper extremity motor task has potential in identifying AD risk. Fifty-four older adults (15 cognitively unimpaired, 24 amnestic mild cognitive impairment, and 15 AD) completed six motor task trials and a structural MRI. Several measures of motor task performance significantly predicted bilateral hippocampal volume, controlling for age, sex, education, and memory. Thus, this motor task may be an affordable, non-invasive screen for AD risk and progression.

The Integration of Tactile and Visual Cues Increases Golf Putting Error in a Mixed-Reality Paradigm.

The integration of visual and tactile cues can enhance perception. However, the nature of this integration, and the subsequent benefits on perception and action execution, are context-dependent. Here, we examined how visual-tactile integration can influence performance on a complex motor task using virtual reality. We asked participants to wear a VR head-mounted display while using a tracked physical putter to make golf putts on a VR golf course in two conditions. In the ‘tactile’ condition, putter contact with the virtual golf ball coincided with physical contact with a physical ball. In a second ‘no tactile’ condition, no physical ball was present, such that only the virtual ball contacted the putter. In contrast to our pre-registered prediction that performance would benefit from the integration of visual and tactile cues, we found golf putting accuracy was higher in the no tactile condition compared to the tactile condition. Participants exhibited higher lateral error variance and over/undershooting when the physical ball was present. These differences in performance between the conditions suggest that tactile cues, when available, were integrated with visual cues. Second, this integration is not necessarily beneficial to performance. We suggest that the decreased performance caused by the addition of a physical ball may have been due to minor incongruencies between the virtual visual cues and the physical tactile cues. We discuss the implications of these results on the use of VR sports training and highlight that the absence of matched tactile cues in VR can result in sub-optimal learning and performance.