No consistent cerebral anatomical abnormality has ever been reported in primary focal hand dystonia (FHD). The present voxel-based morphometry study showed a significant bilateral increase in gray matter in the hand representation area of primary somatosensory and, to a lesser extent, primary motor cortices in 36 patients with unilateral FHD compared with 36 controls. The presence of anatomical changes in the perirolandic cortex for the unaffected hand as well as that for the affected hand suggests that these disturbances may be, at least in part, primary.
Aerobic exercise has been suggested to ameliorate aging-related decline in humans. Recently, evidence has indicated chronological aging is associated with decreases in measures of interhemispheric inhibition during unimanual movements, but that such decreases may be mitigated by long-term physical fitness. The present study investigated measures of ipsilateral (right) primary motor cortex activity during right-hand movements using functional magnetic resonance imaging and transcranial magnetic stimulation (TMS). Healthy, right-handed participant groups were comprised of 12 sedentary older adults, 12 physically active older adults, and 12 young adults. Active older adults and younger adults evidenced longer ipsilateral silent periods (iSP) and less positive BOLD of ipsilateral motor cortex (iM1) as compared to sedentary older adults. Across groups, duration of iSP from TMS was inversely correlated with BOLD activity in iM1 during unimanual movement. These findings suggest that increased physical activity may have a role in decreasing aging-related losses of interhemispheric inhibition.
Purpose Recent investigations into effects of intensity or distribution of aphasia therapy have provided moderate evidence supporting intensive therapy schedules on aphasia treatment response. The purpose of the present study was to investigate the feasibility of creating an intensive therapy session without extending the amount of daily time a person spends in treatment. Method Individuals who presented with chronic anomia poststroke ( N = 8) participated in 2 weeks of a computerized, therapist-delivered, cued, picture-naming treatment. Dosing parameters for each session were 8 presentations of 50 pictures, totaling 400 teaching episodes per session. Results Of the 8 participants, 6 achieved significant increases from baseline on trained items after 400 teaching episodes (i.e., 1 treatment hr), and the remaining 2 participants achieved significant increases from baseline after 1200 teaching episodes (i.e., 3 treatment hr). Maintenance data from 7 of the participants indicated that 6 participants maintained significant improvement from baseline on trained items. Conclusions Given an intensive and saturated context, anomic individuals were surprisingly quick at relearning to produce problematic words successfully. Most participants demonstrated retention of the gains 2 months after treatment ended. The high density of teaching episodes within the treatment session (i.e., the intensive treatment schedule) may have contributed to the behavioral gains.
Evidence indicates that the frequency-domain characteristics of surface electromyogram (EMG) signals are modulated according to the contributing sources of neural drive. Modulation of inter-muscular EMG synchrony within the Piper frequency band (30–60Hz) during movement tasks has been linked to drive from the corticospinal tract. However, it is not known whether EMG synchrony is sufficiently sensitive to detect task-dependent differences in the corticospinal contribution to leg muscle activation during walking. We investigated this question in seventeen healthy older men and women. It was hypothesized that, relative to typical steady state walking, Piper band EMG synchrony of the triceps surae muscle group would be reduced for dual-task walking (because of competition for cortical resources), similar for fast walking (because walking speed is directed by an intermediate locomotor pathway rather than by the corticospinal tract), and increased when taking a long step (because voluntary gait pattern modifications are directed by the corticospinal tract). Each of these hypotheses was confirmed. These findings support the use of frequency-domain analysis of EMG in future investigations into the corticospinal contribution to control of healthy and disordered human walking.
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