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Biomedical subjects

T M Cook

Publications and source records attributed to T M Cook.

At least 73 records · Page 4Linked to original sources

A comparison between the Macintosh and the McCoy laryngoscope blades.

The view of the larynx using the Macintosh laryngoscope and the McCoy levering laryngoscope was assessed in 177 adult patients. The view with the McCoy blade in the neutral position and in the position (neutral or elevated) that gave the 'best' view were recorded. The McCoy blade in the neutral position was associated with a lower incidence of grade 1 views and a higher incidence of grade 2 views than the Macintosh blade. There was no difference in the incidence of grade 3 views. When views for each patient using the different blades were compared, the McCoy blade in the neutral position produced a worse view than the Macintosh blade (p < 0.0001). The view obtained with the McCoy blade in its 'best' position and the Macintosh blade were similar. In the 152 patients in whom the vocal cords were seen using the Macintosh blade, the view was worse using the McCoy blade in its 'best' position more often than it was better (p = 0.06). In 25 patients, the vocal cords could not be seen with the Macintosh blade; in these patients the view was better with the McCoy blade (the cords were visible) on 14 occasions and worse in one (p = 0.001). We conclude that the McCoy blade in its neutral position does not behave identically to the Macintosh blade. The McCoy blade is a useful aid to difficult intubation but should not replace the Macintosh blade as the first choice laryngoscope.

Anesthesia, General↗

Three-dimensional scapular orientation and muscle activity at selected positions of humeral elevation.

Abnormal scapular kinematics and associated muscle function presumably contribute to shoulder pain and pathology. An understanding of scapular kinematic and electromyographic profiles in asymptomatic individuals can provide a basis for evaluation of pathology. The purpose of this study was to describe normal three-dimensional scapular orientation and associated muscle activity during humeral elevation. Twenty-five asymptomatic subjects, 19-37 years old, were evaluated. Digitized coordinate data and surface electromyographic signals from the trapezius (upper and lower), levator scapulae, and serratus anterior were collected at static positions of 0, 90, and 140 degrees of humeral elevation in the scapular plane. The scapula demonstrated a pattern of progressive upward rotation, decreased internal rotation, and movement from an anteriorly to a posteriorly tipped position as humeral elevation angle increased. Electromyographic activity of all muscles studied increased with increased humeral elevation angles. Differences between mean values at all elevation angles for all variables were significant (p < .05), except for the lower trapezius between the 90 and 140 degrees humeral angles. The results of this study suggest assessment of scapular tipping and internal rotation as well as upward rotation may be necessary to understand pathologies of the shoulder that are related to abnormal scapular kinematics.

Adolescent↗

The effect of foot orthotics on three-dimensional kinematics of the leg and rearfoot during running.

Foot orthotics have been used successfully in the treatment of musculoskeletal symptoms associated with structural variations of the foot. Their effectiveness has been primarily addressed through two-dimensional, frontal plane motion studies of the subtalar joint in individuals considered "clinical pronators." Recent evidence suggests that assessment of tibial axial rotation in combination with frontal plane analysis of calcaneal inversion/eversion may provide improved understanding of subtalar joint function. The purpose of this study was to examine the effects of semi-rigid foot orthotics on three-dimensional lower limb kinematics in 20 recreational runners presenting with distinct structural foot characteristics. Radiographic measurements were used to classify subjects into a low or high rearfoot profile group. The results of the kinematic analysis showed a significant orthotic effect for rotations occurring from heel contact to peak tibial internal rotation, as well as in the coupling relationship between tibial axial rotation and calcaneal inversion/eversion. Both groups responded similarly with a mean reduction of 2 degrees in tibial internal rotation. No differences were found for the frontal plane rotations for either group when orthotics were worn. The findings suggest that the maximum effect of orthotics may be realized in the first 50% of stance and related to the changes in tibial axial rotation.

Biomechanical Phenomena↗

Effects of stair-stepping exercise direction and cadence on EMG activity of selected lower extremity muscle groups.

Step ergometry has become a popular treatment mode in cardiovascular fitness and knee rehabilitation programs. The following study describes the effects of forward stair stepping at 35 and 95 steps/minute and forward and retrograde stair stepping at 60 steps/minute on the mean electromyographic (EMG) activity of the gluteus maximus, rectus femoris, vastus medialis, semimembranosus/semitendinosus, and gastrocnemius muscles. Thirty-three subjects without prior lower extremity pathology participated in the study. Analysis of variance was used to compare mean EMG activity during the knee extension phase of the different stepping conditions. Significant differences (p < 0.05) in mean EMGs of gluteus maximus, rectus femoris, vastus medialis, and gastrocnemius were noted across all cadences. The semimembranosus/semitendinosus EMG activity displayed a single significant difference between the cadences of 35 and 95. The comparison between forward and retrograde stepping identified only one significant difference in mean EMG (semimembranosus/semitendinosus). The effects of cadence on EMG activity should be considered when developing conditioning or rehabilitation programs for the lower extremity. Faster cadences result in increased peak activity of shorter duration for the gluteus maximus, quadriceps, and gastrocnemius. There is no apparent difference in EMG activity of the hamstrings due to cadence. Also, noting the minimal activation that occurs, stair-stepping exercise would not be recommended for strengthening of the hamstrings musculature.

Adolescent↗

Active surveillance for the control of cumulative trauma disorders: a working model in the newspaper industry.

Health and risk factor surveillance is a critical aspect of an effective ergonomics process. Physical therapists are becoming increasingly involved in many components of the ergonomics process, including health and risk factor surveillance. The purpose of this study was to develop and implement a multistaged active surveillance program for the management and control of cumulative trauma disorders. The surveillance program was established at three newspaper companies consisting of 1,150 employees. This study focused on the first three stages of the multistage surveillance model, which incorporates the use of symptom and job factor questionnaires, specific anatomical surveys, and clinical detection tests. The results of the study indicated that 1) musculoskeletal symptoms in the back, neck, and hands accounted for the majority of reported missed work among the newspaper workers; 2) production workers had a higher prevalence of musculoskeletal symptoms than office workers; and 3) the prevalence of probable carpal tunnel syndrome among the newspaper workers was 1.5%.

Adolescent↗

Vibration sensibility testing in the workplace. Day-to-day reliability.

Loss of vibration sensibility has been suggested as an early indicator of peripheral compression neuropathy, including carpal tunnel syndrome. Although vibration sensibility has been used frequently to evaluate carpal tunnel syndrome, the day-to-day reliability of vibration measurements in an industrial population measured at the workplace has not been assessed. Vibration sensibility testing was performed at the university ergonomics laboratory on 50 volunteers (100 hands) and at a newspaper company on 50 workers (100 hands). Vibration perception and disappearance thresholds were measured on two occasions separated by 3 to 5 days. Student's t tests indicated no significant differences between the first and second tests or between the two groups. Pearson product-moment correlations for test-retest reliability were lower in the industry group but were relatively high despite the less than optimal testing conditions. Our findings suggest that vibration sensibility measurements are reliable from day to day not only in the laboratory but also in the workplace.

Adult↗

Effects of seated posture on erector spinae EMG activity during whole body vibration.

The purpose of this study was to evaluate the electromyographic (EMG) response of the erector spinae to whole body vibration in three different unsupported seated postures: neutral upright, forward lean, and posterior lean. Subjects were 11 healthy college-age men. EMG was collected using bipolar surface electrodes placed bilaterally over the erector spinae at the L4 level. A modified chair with attached accelerometer was affixed to an induction type vibrator. Subjects were vibrated vertically at 4.5 Hz and 6.21 m.s-2 RMS. Data were collected in each of the three postures for 30 s pre- and post-vibration and for 2 min during vibration. Mean EMG values were determined for each sampling period and compared using ANOVA. The mean value for anterior lean was significantly larger (p < 0.05) than that for posterior lean and neutral. EMG data analysed by triggered averaging showed a phase-dependent response to the vibratory cycle for the forward leaning and neutral upright postures. The results of this study indicate that the magnitude of the vibration synchronous response of the erector spinae musculature is dependent upon body posture. This response may be an important factor in the onset of muscular fatigue and the increased incidence of back disorders among individuals exposed to whole body vibration.

Adult↗