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Biomedical subjects

R A Bogey

Publications and source records attributed to R A Bogey.

6 recordsLinked to original sources
PubMed2005

An EMG-to-force processing approach for determining ankle muscle forces during normal human gait.

Muscle forces move our limbs. These forces must be estimated with indirect techniques, as direct measurements are neither generally possible nor practical. An electromyography (EMG)-to-force processing technique was developed. Ankle joint moments and, by extension, ankle muscle forces were calculated. The ankle moment obtained by inverse dynamics was calculated for ten normal adults during free speed gait. There was close correlation between inverse dynamics ankle moments and moments determined by the EMG-to-force processing approach. Muscle forces were determined. The gait peak Achilles tendon force occurred in late single limb support. Peak force observed (2.9 kN) closely matched values obtained where force transducers were used to obtain in vivo muscle forces (2.6 kN). The EMG-to-force processing model presented here appears to be a practical means to determine in vivo muscle forces.

Adult↗
PubMed1993

The Rancho EMG analyzer: a computerized system for gait analysis.

This paper describes a computer system which accurately defines the EMG patterns of the lower extremities during gait. Footswitches are used to identify the temporal relationships and determine the phases of the gait cycle. Fine wire electrodes, inserted in the desired muscles of the patient being tested, provide EMG signals for comparison with a normal database. The system is also usable with surface electrodes when an appropriate normal database for surface electrodes is incorporated. Descriptive qualifiers (such as 'premature onset', 'delayed cessation', 'no clinically significant EMG', 'continuous activity' etc.) are used to produce a clinically relevant printed (textual) report. The intensity filtered average (IFA) of the EMG is shown graphically with the representative profile of each stride. The IFAs for all muscles tested can be plotted together (up to six on a page) and the graphic representation of the 'raw' EMG can be produced. The methods of generating the normal database by creating time-adjusted mean profiles (TAMP) are enumerated. The clinical use of the system is discussed. A detailed analysis of 31 of the most recent patient tests for which the system was used provides an indication of its accuracy. For 86% of the 428 muscle tests examined, the EMG analyser was considered to have given the correct result as compared with a visual analysis of the raw EMG record by a trained expert. Recommendations for the use and future improvements of the EMG analyser are made.

Adolescent↗
PubMed1993

A computer algorithm for defining the group electromyographic profile from individual gait profiles.

A computer algorithm was developed to determine the group electromyographic (EMG) profile for the soleus muscle during free speed level walking. Subjects consisted of 50 adults (21 male, 29 female) with no history of musculoskeletal disease. EMG was recorded from the soleus muscle with wire electrodes, and was normalized by maximum muscle test. Two algorithms (time-adjusted mean profile (TAMP) and mean intensity profile (MIP)) were implemented to construct a group profile from identical individual EMG profiles. In addition, a grand ensemble average (GEAV) of the same individual data was performed. A high positive correlation (omega 2 > .995) was found between MIP and GEAV of EMG data. A control group was established based on mean timing and relative intensity of the individual EMG profiles. The MIP and GEAV were shown to have earlier onsets, later cessations, and extended EMG duration in comparison to control values. No significant differences were observed comparing TAMP and mean values for any measure.

Adult↗
PubMed1992

Computer algorithms to characterize individual subject EMG profiles during gait.

Three methods of precisely determining onset and cessation times of gait EMG were investigated. Subjects were 24 normal adults and 32 individuals with gait pathologies. Soleus muscle EMG during free speed level walking was obtained with fine wires, and was normalized by manual muscle test (%MMT). Linear envelopes were generated from the rectified, integrated EMG at each percent gait cycle (%GC) of each stride in individual gait trials. Three methods were used to generate EMG profiles for each tested subject. The ensemble average (EAV) was determined for each subject from the mean relative intensity of the linear envelopes. Low relative intensity or short duration EMG was removed from the ensemble average to create the intensity filtered average (IFA). The packet analysis method (PAC) created an EMG profile from the linear envelopes in successive strides whose respective centroid %GC locations were within +/- 15%GC of each other. Control values for onset and cessation times of individual gait trials were calculated after spurious outliers were removed. Mean onset and cessation times across subjects for control values and the experimental methods (EAV, IFA, and PAC) were calculated. Dunnett's test (p less than .05) was performed to compare control and experimental groups in patient and normal trials. EAV differed from control values for onsets (p less than .01), cessations (p less than .01), and durations (p less than .01) in both normal and patient trials. IFA and PAC had no significant differences from control value means. IFA was selected for clinical use as automatic analysis could be performed on all trials and a minimum number of decision rules were needed.

Adult↗
PubMed1986

Heterogeneous mechanical response of rat knee menisci to thermomechanical stress.

Thermodilatometric, dynamic thermomechanical, and light-microscopic analyses were done on the anterior and posterior regions of the rat knee menisci to correlate regional differences in morphology and extracellular matrix composition with regional mechanical behavior. Following the administration of a general anesthetic, menisci were excised from 12 young female Sprague-Dawley rats. During thermodilatometric and thermomechanical testing, tissue temperature was increased at a constant rate of 3.5 degrees C/min from 30 to 100 degrees C. Light microscopy revealed regional differences in cell density and proteoglycan content. The anterior horn was significantly heavier (greater than 87%) and thicker (greater than 60%) than the posterior region. During thermal analyses, both the anterior and posterior horns decreased in tissue thickness as the temperature increased from 30 to 73 degrees C. After 73 degrees C, however, the posterior horn expanded significantly, whereas the anterior remained in a comparatively contracted state. The rates of linear contraction and expansion of the posterior horn were seven times those of the anterior horn, and the stiffness of the anterior horn was significantly greater than the posterior horn.

Analysis of Variance↗