Temporal motor coordination in the ankle joint following upper motor neuron lesions

Comparison of timing and force control of foot tapping between elderly and young subjects

[Purpose] To examine the ability of young and elderly individuals to control the timing and force of periodic sequential foot tapping. [Subjects and Methods] Participants were 10 young (age, 22.1 ± 4.3 years) and 10 elderly individuals (74.8 ± 6.7 years) who were healthy and active. The foot tapping task consisted of practice (stimulus-synchronized tapping with visual feedback) and recall trials (self-paced tapping without visual feedback), periodically performed in this order, at 500-, 1,000-, and 2,000-ms target interstimulus-onset intervals, with a target force of 20% maximum voluntary contraction of the ankle plantar-flexor muscle. [Results] The coefficients of variation of force and intertap interval, used for quantifying the steadiness of the trials, were significantly greater in the elderly than in the young individuals. At the 500-ms interstimulus-onset interval, age-related effects were observed on the normalized mean absolute error of force, which was used to quantify the accuracy of the trials. The coefficients of variation of intertap interval for elderly individuals were significantly greater in the practice than in the recall trials at the 500- and 1,000-ms interstimulus-onset intervals. [Conclusion] The elderly individuals exhibited greater force and timing variability than the young individuals and showed impaired visuomotor processing during foot tapping sequences.

Gait improvement by low-dose botulinum toxin A injection treatment of the lower limbs in subacute stroke patients

[Purpose] Lower-limb spasticity after stroke may be associated with worse functional outcome. Our study aim was to establish whether a low-dose botulinum toxin A (BTX-A) injection in subacute stroke patients can improve spasticity, gait, and daily living abilities. [Subjects] Twenty-three subacute stroke patients were randomly allocated to BTX-A treatment group (11 patients) and control group (12 patients). [Methods] In the BTX-A treatment group patients, 200 units BTX-A was injected into the triceps surae (150 iu) and posterior tibial (50 iu) by electrical stimulation-guided. The patients in the control group received the same volume of placebo solution into the same injection locations. Gait analysis (step length, cadence, speed), the 6-min walking test, Fugl-Meyer Assessment (FMA) of the lower limbs, modified Ashworth scale assess (MAS) assessment of the lower limbs, surface electromyography (sEMG), and modified Barthel index (MBI) assessment were performed before and at 4,8 weeks after treatment. [Results] We found that the FMA of the low limbs and MBI were significantly improved in both groups. The gait analysis, FMA, and MBI results in the BTX-A treatment group were better than those in the control group. MAS and surface electromyography (sEMG) showed better improvement of spasticity in the treatment group. [Conclusion] Early low-dose botulinum toxin A (BTX-A) injection in subacute stroke patients into the lower-limb may improve gait, spasticity, and daily living abilities.