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Biomedical subjects

Valeriya Gritsenko

Publications and source records attributed to Valeriya Gritsenko.

2 recordsLinked to original sources

A functional electric stimulation-assisted exercise therapy system for hemiplegic hand function.

OBJECTIVE: To test a functional electric stimulation (FES)-assisted exercise therapy system for improvement of motor function of the hemiplegic upper extremity. DESIGN: A before-after trial, with 2-month follow-up. SETTING: A university research laboratory. PARTICIPANTS: A convenience sample of 6 subjects (3 men, 3 women). Main inclusion criteria were that stroke had occurred more than 1 year before the study (mean time poststroke, 5.6+/-4.4y) and had resulted in hemiplegia, and that FES produced adequate hand opening. INTERVENTION: A prototype workstation with instrumented objects was used by subjects to perform a set of tasks with their affected hand during 1-hour sessions for 12 consecutive workdays. A FES stimulator was used to assist hand opening. Main outcome measures Kinematic data, provided by the workstation sensors, and 3 clinical tests. RESULTS: Kinematic data indicated statistically significant improvement in subjects' performance (pre-/posttreatment effect size [pre/post ES] of the mean performance scores=5.46; mean pretreatment/follow-up ES [pre/FU ES]=3.44). Two of 3 clinical tests showed improvement in hand function (mean pre/post ES=.51; mean pre/FU ES=.61). CONCLUSIONS: Improvement in hemiplegic hand function because of FES-assisted therapy was documented in a small group of people with hemiplegia whose motor impairment would exclude them from participation in constraint-induced movement therapy. However, the long-term clinical relevance of such improvement needs further study.

Analysis of Variance↗

Sensory control of locomotion: reflexes versus higher-level control.

In the absence of sensory input, the central nervous system can generate a rhythmical pattern of coordinated activation of limb muscles. Contracting muscles have spring-like properties. If synergistic muscles are co-activated in the right way, sustained locomotion can occur. What is the role of sensory input in this scheme? In this chapter we first discuss the implications of positive force feedback control in hindlimb extensor reflexes in the cat. We then raise the question of whether the sensory-evoked responses, which are modest in size and quite delayed in the stance phase, contribute to any significant extent. A locomotor model is used to show that when centrally generated activation levels are low, stretch reflexes can be crucial. However, when these levels are higher, stretch reflexes have a less dramatic role. The more important role for sensory input is probably in mediating higher level control decisions.

Animals↗