Faculty Bibliography

A new triaxial dynamometer to quantify the performance of trunk muscles has been developed, and a study was conducted to determine the best control parameters to use with this triaxial isodynamic mode of testing. Nine male subjects were tested at three resistance levels in the sagittal, coronal, and transverse planes. The purpose was to establish the reproducibility of the performance parameters in each plane at all resistance levels, and to identify those parameters which gave the most reliable information for objective assessment of the low back functional state. Measured torque had the highest reproducibility rate, and the most reliable assessments were obtained at the highest resistance level

Previous studies have shown that reduction of precise motor control accompanies local muscular fatigue. The effects of isodynamic fatiguing of flexion and extension trunk movements on the movement patterns and the motor output of the trunk were investigated. Twenty male subjects with no history of low-back pain for the past 6 months volunteered for the study. A triaxial dynamometer was used that simultaneously provided measurement of torque, angular position and velocity of each axis. Resistances were set independently for each axis by an interfaced computer. The subjects performed trunk flexion and extension movement against a sagittal plane resistance equal to 70% of their maximum isometric extension strength in the upright position. The minimum resistances in the coronal and transverse planes were set up at 7 Newton meters. The subjects were asked to perform trunk movement as quickly and as accurately as possible while exerting the maximum efforts until exhaustion. Analysis of variance, the MANOVA procedure with a repeated measure design, was performed among the selected parameters of the first, middle and last three repetition cycles. The selected parameters are the trunk motor output and movement patterns; the total angular excursion, range of motion, maximum and average torque and angular velocity of the trunk. All the selected parameters were significantly reduced in the sagittal plane. Subjects displayed significantly less motor control and greater range of motion in the coronal and transverse planes in performing the primary task of flexion and extension. The reduction in the functional capacity of the primary muscles performing the required task is compensated by secondary muscle groups and the spinal structure is loaded in a more injury prone pattern, as identified by finite element models. In addition it is suggested that the fatigued muscles would be less able to compensate any perturbation in the load or position of the trunk. The repetitive loading results in a weakening of the viscoelastic passive elements of the spineless structure. The loss of ability to protect these weakened passive elements makes the spine susceptible to industrial and recreational injuries

Long-term surveillance of Huntington's disease families living in South Wales has been undertaken since 1973. We report the updated data on prevalence and births in 101 kindreds. The trend in the births at risk of Huntington's disease has been compared with a control population in North Wales

The purpose of this study was to evaluate the limitation of motion as well as comfort provided by four different types of lumbar braces. The four braces were the Raney jacket, the Camp lace-up corset, a molded-polypropylene thoracolumbar-sacral orthosis (TLSO), and a common elastic corset. The data revealed that all braces significantly restrict free lumbar and thoracic motion in the sagittal and frontal planes. All braces restricted lumbar motion more in the frontal than in the sagittal plane. The rigid TLSO and Raney jackets were most restrictive when compared with the Camp corset and the elastic corset. Axial rotation in the lumbar spine is normally minimal and further limitation by a brace would be negligible. All braces restricted thoracic motion despite the fact that lumbar braces were used. The elastic corset was rated the most comfortable and the Raney jacket the least comfortable. This verifies that there is an inverse relationship between a brace's ability to restrict motion and comfort

This study examines the application of a new noninvasive technology capable of accurately, reproducibly, and reliably measuring spinal motion, in real time, with 3 df. The mean values and SD of range of motion in the lumbar, thoracic, and cervical regions compares favorably with results reported by other authors. Pearson correlations yielded a statistically significant weak inverse relationship between age and range of motion in the sagittal and frontal planes (p less than .02). No correlation between sex, height, or weight and range of motion was found. There was no statistically significant evidence of organized coupling. However, a relationship between rotation and lateral motion in the thoracic region was noted

1. Transcranial cortical stimuli (TCCS) were used to elicit motor responses in contralateral wrist flexor and extensor muscles of healthy adult subjects. The motor responses were assessed by surface EMG recordings, by needle recordings of single motor-unit discharges, and by measurements of wrist twitch force. Our main aim was to analyze the single-unit events underlying those changes in latency, amplitude, and duration of the compound EMG responses, which could be induced by voluntary preactivation of target muscles and by changes in stimulation strength. 2. Different stimulus strengths were tested with and without background contractions in the flexor or extensor muscles. For each test (consisting of a series of 20 stimuli) the compound EMG responses were averaged and displayed together with the averaged wrist force signals. Responses of individual flexor and extensor motor units were displayed in raster diagrams and peristimulus time histograms. For units exhibiting a background firing, the mean background interdischarge interval was calculated and compared with the subsequent poststimulus intervals. 3. In relaxed muscles, a shortening of onset latency of evoked compound EMG responses was observed when raising stimulation strength. A similar latency reduction was not seen in any of the single-unit recordings. This would be consistent with the size principle of motoneuron recruitment. 4. A shortening of onset latency of evoked EMG potentials was observed also as a result of a voluntary preactivation. Such latency shifts, which were seen also in single-unit recordings, might be attributed to variations in the time required for D and I wave temporal summation at the anterior horn cell. 5. When raising stimulation strength or when adding voluntary background contraction, the evoked compound EMG potential grew not only in amplitude but also in duration, as later peaks of activity were added to the initial ones. Under optimal conditions (strong stimulus + background contraction), the period of excitation (termed E1) had an onset latency of approximately 15 ms and a duration of approximately 35 ms and was similar for wrist flexor and extensor muscles. 6. We never saw the same flexor or extensor unit fire more than once during the E1 period. For units preactivated by a background contraction, the stimulus-triggered impulse exhibited latency shifts, which, to a large extent, depended on the timing of the stimulus in relation to a preceding background discharge and which could be influenced by a change in stimulation strength.(ABSTRACT TRUNCATED AT 400 WORDS)

This paper makes general recommendations for workstation design. To prevent back problems, a chair should maintain a 105 degrees angle between the trunk and the thighs. For bent-forward work, a seat pan that can tilt forward allows the critical angle to be maintained

Neurologic outcome of hypoxic ischemic coma after cardiac arrest was studied in 32 patients. Observations were made and samples collected 24 and 48 h after the ischemic insult. The Glasgow-Pittsburgh coma score was assessed for its prognostic value. Other variables studied were the EEG and adenylate kinase, lactate and glutathione in the cerebrospinal fluid (CSF). Outcome was termed good if the patients resumed an independent life within a 6-month follow-up period. The closest correlations between prediction and good outcome occurred with the Glasgow-Pittsburgh coma score (94%) and the EEG (77%) at the 48-h examination, a modified coma score (96%) at 48 h, and CSF lactate (78%) at 24 h. Some simple neurologic signs (e.g., no withdrawal response to pain) at stated points in time was 100% associated with a bad outcome, although their absence was not associated necessarily with a good prognosis