Combining Muscle Stimulation with Elicitation of the Nociceptive Withdrawal Reflex in a Gait Controller to Support Hemiparetic Gait
Authors
Nielsen, Nikolaj Børty ; Bjerre, Lotte
Term
4. term
Publication year
2011
Submitted on
2011-05-31
Pages
132
Abstract
Mange personer, der har haft en apopleksi, får et ujævnt gangmønster. De har ofte svært ved at løfte foden i svingfasen (når benet føres frem) og at holde det svækkede ben stabilt i standfasen (når foden er i gulvet). Denne afhandling har designet og bygget en gangcontroller, der bruger funktionel elektrisk stimulation (FES)—små, tidsbestemte elektriske impulser til musklerne—til at støtte gang ved hemiparese (svaghed i den ene side). Tilgangen stimulerer quadriceps (lårmuskel på forsiden) og soleus (lægmuskel) i standfasen for at støtte benet og udløser den nociceptive tilbagetrækningsrefleks (NWR)—en beskyttende refleks fremkaldt ved stimulering af fodsålen—for at starte svingfasen. For at informere designet undersøgte vi, hvordan NWR moduleres under gang hos fire deltagere med normal gang og hos én deltager med hemiparetisk gang. Hofte-, knæ- og ankelbevægelserne afhang af, hvor på fodsålen og hvornår der blev stimuleret. På baggrund af disse indsigter blev der udviklet en sekvensbaseret stimuleringscontroller (SBS), der bedre matchede behovene ved hemiparetisk gang. Hos én hemiparetisk deltager blev SBS-controlleren testet mod en enklere controller med fast stimuleringsmønster (FPS). For denne deltager gav SBS bedre støtte. Fundene fra dette meget lille materiale peger på, at træningsforløb, der aktiverer quadriceps og soleus i standfasen og udløser NWR for at starte svingfasen, kan hjælpe genoptræning af gang efter apopleksi.
Many people who have had a stroke develop an uneven walking pattern. They often struggle to lift the foot during the swing phase (when the leg moves forward) and to keep the weakened leg stable during the stance phase (when the foot is on the ground). This thesis designed and built a gait controller that uses functional electrical stimulation (FES)—small, timed electrical pulses to muscles—to assist walking in hemiparesis (weakness on one side). The approach stimulates the quadriceps (front thigh muscle) and soleus (calf muscle) during stance to support the limb, and triggers the nociceptive withdrawal reflex (NWR)—a protective reflex evoked by stimulating the sole of the foot—to initiate the swing phase. To guide the controller design, experimental studies examined how the NWR is modulated during walking in four participants with normal gait and in one participant with hemiparetic gait. The hip, knee, and ankle movements depended on the location on the sole of the foot and on the timing of the stimulation. Using these insights, a sequence-based stimulation (SBS) controller was developed to better match the needs of hemiparetic walking. In a single hemiparetic participant, the SBS controller was tested against a simpler fixed-pattern stimulation (FPS) controller. For that participant, the SBS provided superior support. These findings, from a very small sample, suggest that training protocols that activate the quadriceps and soleus during stance and elicit the NWR to start swing may help retrain walking after stroke.
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