Trial Outcomes & Findings for Neural Prostheses and Gait Performance: Model-Based Strategies (NCT NCT00991406)

Results Overview

This was a feasibility study of computational models and gait simulations to objectively determine patient-specific patterns of muscle activation. We developed computer models and walking simulations of hemiplegic gait from 8 subjects. We related the model results (muscle activations) to the optimized data collected from hemiplegic subjects \& calculated the FES pattern to be delivered in 2 forms (open loop \& foot switch triggered). The primary outcome measure turned out to be the feasibility of the methods because after developing our computer modeling and computational optimization framework we could only test walking with the 2 forms of FES at the same preferred walking speed on a treadmill. Thus, the simulated walking speed and the real walking speed pre and post FES turned out to be the same. Walking stability was measured with variability in work performed at the ankle. The additional volitional and FES biomechanical data that were measured are listed in the secondary measures.

Recruitment status

COMPLETED

Study phase

NA

Target enrollment

9 participants

Primary outcome timeframe

pre-stimulation (volitional) and post-stimulation (FES), day of the study

Results posted on

2019-08-09

Participant Flow

Computational optimization was via tracking joint angles \& ground reaction forces from an able walking subject.We optimized the hemiparetic (HP) subject's model to able data \& their walking data producing optimization solutions for muscle activations in each case.The able subject was not considered enrolled,only 9 HPsubjects were actually enrolled.

Participant milestones

Participant milestones
Measure	Arm 1: FES Case-control study: pre- and post-stimulation (FES). FES: Surface stimulation to contract the muscles in the lower extremity
Overall Study STARTED	9
Overall Study COMPLETED	8
Overall Study NOT COMPLETED	1

Reasons for withdrawal

Reasons for withdrawal
Measure	Arm 1: FES Case-control study: pre- and post-stimulation (FES). FES: Surface stimulation to contract the muscles in the lower extremity
Overall Study One participant did not respond to FES.	1

Baseline Characteristics

Race and Ethnicity were not collected from any participant.

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Arm 1: FES n=8 Participants Case-control study: pre- and post-stimulation (FES). FES: Surface stimulation to contract the muscles in the lower extremity where subjects serve as their own control.
Age, Categorical <=18 years	0 Participants n=8 Participants
Age, Categorical Between 18 and 65 years	2 Participants n=8 Participants
Age, Categorical >=65 years	6 Participants n=8 Participants
Age, Continuous	64.1 years STANDARD_DEVIATION 14.0 • n=8 Participants
Sex: Female, Male Female	2 Participants n=8 Participants
Sex: Female, Male Male	6 Participants n=8 Participants
Region of Enrollment United States	8 Participants n=8 Participants

PRIMARY outcome

Timeframe: pre-stimulation (volitional) and post-stimulation (FES), day of the study

Population: Volitional and FES data available for participants with hemiparesis.

This was a feasibility study of computational models and gait simulations to objectively determine patient-specific patterns of muscle activation. We developed computer models and walking simulations of hemiplegic gait from 8 subjects. We related the model results (muscle activations) to the optimized data collected from hemiplegic subjects \& calculated the FES pattern to be delivered in 2 forms (open loop \& foot switch triggered). The primary outcome measure turned out to be the feasibility of the methods because after developing our computer modeling and computational optimization framework we could only test walking with the 2 forms of FES at the same preferred walking speed on a treadmill. Thus, the simulated walking speed and the real walking speed pre and post FES turned out to be the same. Walking stability was measured with variability in work performed at the ankle. The additional volitional and FES biomechanical data that were measured are listed in the secondary measures.

Outcome measures

Outcome measures
Measure	Arm 1: FES n=8 Participants Case-control study: pre- and post-stimulation (FES). FES: Surface stimulation to contract the muscles in the lower extremity
Walking Stability and Speed Volitional	0.1055 Joules/body mass in kilograms Standard Deviation 0.0117
Walking Stability and Speed FES: Open loop	0.0390 Joules/body mass in kilograms Standard Deviation 0.0716
Walking Stability and Speed FES: Foot switch Trigger	0.0206 Joules/body mass in kilograms Standard Deviation 0.0209

SECONDARY outcome

Timeframe: Same day: pre-stimulation (volitional) and post-stimulation (FES), day of the study

Population: Volitional and FES data available for participants with hemiparesis.

This is the peak ankle power during walking normalized by body weight.

Outcome measures

Outcome measures
Measure	Arm 1: FES n=8 Participants Case-control study: pre- and post-stimulation (FES). FES: Surface stimulation to contract the muscles in the lower extremity
Peak Ankle Power Volitional	0.9162 Watts/body mass in kilograms Standard Deviation 1.0242
Peak Ankle Power FES: Open Loop	1.1392 Watts/body mass in kilograms Standard Deviation 1.1438
Peak Ankle Power FES: Foot switch Trigger	0.6315 Watts/body mass in kilograms Standard Deviation 0.6106

SECONDARY outcome

Timeframe: Same day; pre-stimulation (volitional) and post-stimulation (FES), day of the study

Population: Volitional and FES data available for participants with hemiparesis.

This is the amount of positive work performed by the ankle during walking normalized by body mass.

Outcome measures

Outcome measures
Measure	Arm 1: FES n=8 Participants Case-control study: pre- and post-stimulation (FES). FES: Surface stimulation to contract the muscles in the lower extremity
Positive Ankle Work Volitional	0.1097 Joules/body mass in kilograms Standard Deviation 0.0909
Positive Ankle Work FES: Open loop	0.1423 Joules/body mass in kilograms Standard Deviation 0.1122
Positive Ankle Work FES: Foot switch Trigger	0.0869 Joules/body mass in kilograms Standard Deviation 0.0447

SECONDARY outcome

Timeframe: Same day: pre-stimulation (volitional) and post-stimulation (FES), day of the study

Population: Volitional and FES data available for participants with hemiparesis.

The is the magnitude of ground reaction force over time per step in the anterior direction during walking.

Outcome measures

Outcome measures
Measure	Arm 1: FES n=8 Participants Case-control study: pre- and post-stimulation (FES). FES: Surface stimulation to contract the muscles in the lower extremity
The Impulse of the Anterior Ground Reaction Force Normalized by Body Mass. Volitional	0.0100 Newtons*seconds/body mass in kilograms Standard Deviation 0.0081
The Impulse of the Anterior Ground Reaction Force Normalized by Body Mass. FES: Open loop	0.0106 Newtons*seconds/body mass in kilograms Standard Deviation 0.0081
The Impulse of the Anterior Ground Reaction Force Normalized by Body Mass. FES: Foot switch Trigger	0.0109 Newtons*seconds/body mass in kilograms Standard Deviation 0.0102

Adverse Events

Arm 1: FES

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Elizabeth Hardin

Cleveland VAMC

Phone: 216-791-3800

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place