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Biomedical subjects

M Kljajić

Publications and source records attributed to M Kljajić.

14 recordsLinked to original sources

Enhanced rehabilitation of gait after stroke: a case report of a therapeutic approach using multichannel functional electrical stimulation.

The beneficial effects of using multichannel functional electrical stimulation (MFES) for gait rehabilitation in nonambulatory hemiplegic patients have already been shown. The methodology of application and the results presented were pooled for the whole group of participants, which blurs the exact picture of each particular subject and many vital details are not presented. The purpose of this article is to focus on a single subject from the study and to present all the details of the treatment. The presented subject participated six weeks in the study, first three weeks in MFES therapy and second three weeks in conventional therapy. The effects of each therapy were evaluated by the following measures: temporal-distance parameters of gait, ground reaction forces, goniograms in hip knee and ankle, and assessment of the physical status of the patient according to the Fugl-Meyer evaluation scale. An analysis of the measured parameters showed improved performance of the patient during MFES therapy and stagnation or even slight recession during conventional therapy. The patient achieved independent gait during the three weeks of MFES therapy. At 30 months after the beginning of therapy, the patient was still able to ambulate independently without any significant changes in his gait pattern. The accomplishment was mainly attributed to the avoidance of pathological gait pattern development by using MFES assisted gait training and to the high motivation of the patient to walk and exercise during therapy as well as after he was released to go home.

Activities of Daily Living↗

The rehabilitation of gait in patients with hemiplegia: a comparison between conventional therapy and multichannel functional electrical stimulation therapy.

BACKGROUND AND PURPOSE: Gait rehabilitation in patients with severe hemiplegia requires substantial effort. Preliminary studies indicate potential beneficial effects of using multichannel functional electrical stimulation (MFES) for gait rehabilitation in these patients. In this study, a new method of gait rehabilitation for nonambulatory patients with hemiplegia by means of MFES added to conventional therapy was introduced. The results of the method's application were evaluated by comparing it with conventional therapeutic methods. SUBJECTS: The proposed rehabilitation method was tested on a group of 20 patients with severe hemiplegia secondary to cerebrovascular accident. Subjects were randomly assigned to one of two groups. One group received 3 weeks of MFES followed by 3 weeks of conventional therapy. The other group received 3 weeks of conventional therapy followed by 3 weeks of MFES. METHODS: The effects of each therapeutic method were evaluated by measurements of temporal-distance variables and ground reaction forces and by assessment of each subject's physical status according to the Fugl-Meyer evaluation scale. RESULTS: There was improved performance of the subjects during MFES combined with conventional therapy as compared with conventional therapy alone. CONCLUSION AND DISCUSSION: The superiority of the MFES method as compared with conventional therapy was mainly attributed to the enhanced motor learning accomplished by application of MFES. These results, however, are preliminary, and further research is needed.

Adult↗

Application of a programmable dual-channel adaptive electrical stimulation system for the control and analysis of gait.

A dual-channel electrical stimulation system with a stimulator and a programmer/stride analyzer was designed for clinical rehabilitation of gait and for subsequent daily use as an orthotic aid. The stimulator, with controls to adjust amplitude only (50 mA), adapts chosen stimulation sequences to the walking rate of a patient. Pulse duration (50-500 microseconds), frequency (5-120 Hz), shape (symmetrical biphasic, monophasic), stimulation sequences (16 stride segments) and their cycle (2-12 sec), and right/left foot-switch choices are selected for each patient and programmed into a separate unit. The programming unit also statistically processes the foot-switch data collected by the stimulator. The device was evaluated with regard to the programmable parameters, effectiveness during gait, and feasibility in clinical use. It was applied to 11 stroke patients and 10 brain injury patients during gait, stimulating 22 combinations of peroneal nerve and hamstring, quadriceps, triceps brachii, and gluteus maximus muscles. Forces on both feet, equinovarus, knee extension and hyperextension, elbow flexion, and hip extension were corrected. Selection of the stimulation sequences, their adaptation, range of pulse duration, and valid statistics were verified. Improved forces and joint angles were recorded together with significant changes in the stride time, length, and velocity by the stimulation.

Adult↗

Gait evaluation in hemiparetic patients using subcutaneous peroneal electrical stimulation.

In hemiparetic patients with an implantable peroneal stimulator for correction of drop foot the gait pattern was studied over several years. The gait parameters and M-waves of subcutaneously stimulated muscles were compared with the results obtained before implantation and their variation was observed over time. Of a group of 35 patients with previously implanted electrodes 19 were evaluated. Significant improvements of gait were found although in some cases an excessive eversion of the foot was observed. Nine of these patients had reimplantation because of displacement of the stimulation electrodes after an average time of 3.5 years of proper functioning of the implant. After the reimplantations, similar gait patterns and muscular responses to stimulation were observed as after the initial implantation.

Electric Stimulation Therapy↗

Restoration of gait during two to three weeks of therapy with multichannel electrical stimulation.

Multichannel electrical stimulation was applied in 20 patients with hemiplegia secondary to stroke or head injury using a six-channel microprocessor stimulator-stride analyzer to restore independent gait and to reestablish a normal gait pattern in a two- to three-week therapy period. The therapy was followed up at every session by a stride analyzer incorporated into the stimulator. At the beginning and at the end of the therapy period, each subject's gait was measured with a ground reaction measuring system. Statistical results and observations are presented for the group of 20 subjects, and a detailed description of the results is given for one subject who is representative of the whole group. According to the measured gait characteristics, gait improved significantly in all subjects during the therapy period, resulting in a partly or completely independent gait. The subjects' posture and endurance also improved, and they spontaneously learned how to use a crutch. The measurements and visual assessment of the subjects' progress indicate that the described treatment protocol offers good prospects for faster and more efficient gait rehabilitation in severely impaired patients. To determine the efficacy of gait therapy with multichannel electrical stimulation, a comparative study of conventional therapeutic methods and the method described in this article should be conducted.

Adolescent↗

A quantitative method of evaluation of gait under the influence of electrical stimulation in hemiparetic patients.

To improve the procedure of selecting stimulation parameters for the best functional movement, quantitative gait evaluation was investigated. Based on the information obtained by force measuring shoes and a goniometric system, the method consists of computing average values and standard deviations of ground reaction and its point of action, goniometric functions, as well as the ankle joint torque in the sagittal and frontal plane, and their graphic representation. Deviation of the measured variables with respect to the normal gait pattern is the measure of the gait quality. Stimulation parameters were adjusted so that the patient's gait pattern approached normal.

Electric Stimulation↗

The use of ground reaction measuring shoes in gait evaluation.

Ground reaction force is one of the most relevant parameters in the assessment of human gait. It is, however, difficult to measure without encumbering natural locomotion. A description of a system for measuring the vertical component of the ground reaction force and its distribution under the foot is given. The calibration procedure for the measuring shoes is described. The results of measurements are compared with those obtained from a force plate. Illustrative examples of the changes in pathological gait patterns of a hemiplegic patient during therapy by functional electrical stimulation are also given.

Biomechanical Phenomena↗

Therapeutic effects of multisite electric stimulation of gait in motor-disabled patients.

Therapeutic effects in ten hemiplegic patients and one paraparetic patient treated by multisite electric stimulation of gait were compared with effects in ten hemiplegic patients treated by standard rehabilitation methods after 2.6 months of extensive therapy. Average step length and gait velocity, ground reaction forces and their distribution under both feet, and crutch loading were measured; goniograms of joint angles, kinesiologic gait analysis, and EMG recordings from the main muscles used in ambulation and in standing, were made while patients in both groups walked without stimulation. Quantitative measurements before, during, at the end, and 8.4 months posttherapy were taken based on at least 40 strides per patient. The results for the stimulated group in midtherapy indicated faster recovery rates (3.15 times in step length and 2.25 times in gait velocity) than in the control group, and at the end of therapy the stimulated group had higher improvement levels (2.14 times in step length, 1.42 times in gait velocity, and 1.63 times in kinesiologic gait analysis). The differences between the two groups faded after 8.4 months without treatment, and some kinesiologic deficits reappeared, mostly those in the more distal muscle groups. These findings indicate a need for a simpler orthotic electric stimulation after multisite therapy in several cases. Immediate effects of the six-site stimulation were also considered for orthotic possibilities after the therapy.

Electric Stimulation Therapy↗

Standardization of kinematic gait measurements and automatic pathological gait pattern diagnostics.

The estimation of patients gait in the field of rehabilitation is the starting point for an appropirate therapy decision and convenient prosthesis or orthosis choice. The measurement and estimation of human locomotion is increasingly being transferred to every day clinical use. In recent times many systems are intended for kinematic gait parameters measurements: stroboscopic photography, movie camera, TV picture analysis, TV signal analysis, chronocyclographical measurement, polarised light goniometer, the "Selspot" system, parallelgram goniometers, exoskeleton goniometers. In the paper the role of the computer in gait measurements is also determined. The problems of the choice of parameters to be measured, unique reference coordinate systems and normal gait pattern are encountered in this work. Finally two versions of pathological gait pattern estimation are described: clinical gait analysis and mathematical quantitative gait analysis. A combination of both methods provides an efficient, compact automatic pathological gait pattern diagnostics.

Automation↗

Implantable stimulator for selective stimulation of the common peroneal nerve: a preliminary report.

We present details of the modelling, design, and experimental testing of an implantable system with a monopolar half-cuff electrode for selective stimulation of fibres within certain superficial regions of the human common peroneal nerve which is capable of making a selective activation of muscles, thus contributing to strong dorsal flexion and moderate eversion of the hemiplegic foot. The development of the cuff electrode was based partly on data obtained from histological examination of human common peroneal nerves, and from previously described models of excitation of myelinated nerve fibres. The modelling objectives were to determine the electric field that would be generated within the deep peroneal branch of the nerve by a monopolar half-cuff electrode installed on the nerve behind the lateral head of the fibula. The extent of initial excitation of the nerve fibres within the superficial region of the deep peroneal branch elicited by a monopolar half-cuff electrode was predicted. In the past 6 months two systems were implanted. In both patients significant improvements of gait dynamics were observed.

Action Potentials↗