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Biomedical subjects

G T Allison

Publications and source records attributed to G T Allison.

28 records · Page 2Linked to original sources
PubMed1999

Comparison of ribcage and posteroanterior thoracic spine stiffness: an investigation of the normal response.

Evaluation of the movement response to posteroanterior (PA) loads applied to the spinous processes is a recognized part of the physical examination of the thoracic spine. During this clinical procedure the thoracic spine is supported by the ribcage which may contribute to the movement response. However, the contribution of ribcage stiffness to the PA stiffness of the thoracic spine has not been established. The purpose of this study was to measure the PA stiffness of the thoracic spine and compare this to the stiffness of the ribcage under anteroposterior load. Using force-displacement analysis, this study measured the PA stiffness of the thoracic spine at T4, T7 and T10 in 20 asymptomatic individuals, and compared this to the ribcage stiffness measured through sternal compression. The mean PA stiffness at T7 (10.7 N/mm) was significantly greater than at T4 (9.1 N/mm, P < 0.001), and there was a non-significant increase between T7 and T10 (11.4 N/mm, P = 0.08). The stiffness of the ribcage measured via sternal compression (7.6 N/mm) was significantly lower than the thoracic PA stiffness at all levels (P < 0.01). A significant proportion (33%) of the thoracic spine PA stiffness was accounted for by the stiffness of the ribcage (P < 0.01). In young, asymptomatic subjects, the PA stiffness of the thoracic spine is significantly greater than the stiffness of the ribcage. This suggests that the response to PA load application in the thoracic spine can be attributed to factors relating to the spine as well as the ribcage. Defining consistent patterns of PA stiffness in the thoracic spine may assist in the interpretation of clinical measurements of patients with mechanical dysfunction of the thoracic spine.

Adult↗
PubMed1998

EMG signal amplitude assessment during abdominal bracing and hollowing.

Motor pattern re-education is often used by clinicians as part of treatment regimens for chronic low back pain. Such programmes are often validated by the analysis of the electromyographical (EMG) signal from specific muscles. Independent muscles are often compared using the raw amplitude of the EMG signal or comparing the ratio of the amplitudes of two muscles. Statistical inferences from these derived data may depend on minimizing the sources of error when manipulating the EMG signal profile data. This is particularly true for amplitude normalization procedures, their reliability and the subsequent derivation of amplitude ratios. The purpose of the study was first to examine the reliability of five amplitude normalized procedures and second to examine the sensitivity of raw versus ratio amplitude comparisons during two different abdominal muscle exercises. The study demonstrated that maximal effort amplitude normalization techniques reduce the sensitivity of raw data comparisons, but had little influence on the sensitivity of the ratio data in differentiating the two movement patterns. It was concluded that using the EMG signal profile to identify pathological movement strategies, in association with regional pain syndromes, needs special attention to the reliability and validity of the derived variables.

Abdominal Muscles↗
PubMed1998

Altered abdominal muscle recruitment in patients with chronic back pain following a specific exercise intervention.

The efficacy of specific exercise interventions that advocate training the co-contraction of the deep abdominal muscles with lumbar multifidus for treating chronic back pain conditions has not been tested. A randomized controlled trial involving 42 subjects with a specific chronic back pain condition investigated whether this form of intervention results in changes to the ratio of activation of the internal oblique relative to the rectus abdominis. Data were collected before and after the intervention, using surface electromyography, while subjects performed different abdominal maneuvers. Subjects were randomly allocated to either a specific exercise group or control group. Following intervention, the specific exercise group showed a significant (p < 0.05) increase in the ratio of activation of the internal oblique relative to the rectus abdominis. The control group showed no significant change. The study findings provide evidence that the conscious and automatic patterns of abdominal muscle activation can be altered by specific exercise interventions.

Abdominal Muscles↗
PubMed1998

Influence of load orientation on the posteroanterior stiffness of the lumbar spine.

OBJECTIVE: To compare the posteroanterior (PA) stiffness of the lumbar spine when the load is applied in a vertical direction with the stiffness when the load is applied perpendicular to the spinal curve. DESIGN: The PA stiffness of the lumbar spine was assessed at L1, L3 and L5 on 24 normal subjects using a mechanical spinal mobilization apparatus. The PA stiffness was measured when the load was applied in a vertical direction and when the load was applied perpendicular to the spinal curve at the level being tested. SETTING: A university biomechanics laboratory. DESIGN: A repeated-measures design with pseudorandomization of the order of testing. MAIN OUTCOME MEASURES: Stiffness variable derived from force-displacement curve. RESULTS: The difference in PA stiffness between the two loading conditions was small at all three levels tested. The stiffness of L5 was significantly lower when the load was applied in the vertical direction compared with the application of the load in the perpendicular direction (p = .0001). Altering the angle of inclination of PA load had no statistically significant effect on PA stiffness at L1 and L3. The mean PA stiffness of the lumbar spine increased in a caudal direction (L1 = 10.4 N/mm, L3 = 11.4 N/mm, L5 = 11.6 N/mm). CONCLUSION: The orientation of the PA load had only a small effect on the measured PA stiffness and would be unlikely to be detected during manual examination of the spine. However, changes in the orientation of the PA load may be important when considered in relation to the symptom response.

Adult↗
PubMed1997

Evaluation of specific stabilizing exercise in the treatment of chronic low back pain with radiologic diagnosis of spondylolysis or spondylolisthesis.

STUDY DESIGN: A randomized, controlled trial, test--retest design, with a 3-, 6-, and 30-month postal questionnaire follow-up. OBJECTIVE: To determine the efficacy of a specific exercise intervention in the treatment of patients with chronic low back pain and a radiologic diagnosis of spondylolysis or spondylolisthesis. SUMMARY OF BACKGROUND DATA: A recent focus in the physiotherapy management of patients with back pain has been the specific training of muscles surrounding the spine (deep abdominal muscles and lumbar multifidus), considered to provide dynamic stability and fine control to the lumbar spine. In no study have researchers evaluated the efficacy of this intervention in a population with chronic low back pain where the anatomic stability of the spine was compromised. METHODS: Forty-four patients with this condition were assigned randomly to two treatment groups. The first group underwent a 10-week specific exercise treatment program involving the specific training of the deep abdominal muscles, with co-activation of the lumbar multifidus proximal to the pars defects. The activation of these muscles was incorporated into previously aggravating static postures and functional tasks. The control group underwent treatment as directed by their treating practitioner. RESULTS: After intervention, the specific exercise group showed a statistically significant reduction in pain intensity and functional disability levels, which was maintained at a 30-month follow-up. The control group showed no significant change in these parameters after intervention or at follow-up. SUMMARY: A "specific exercise" treatment approach appears more effective than other commonly prescribed conservative treatment programs in patients with chronically symptomatic spondylolysis or spondylolisthesis.

Adult↗
PubMed1997

Assisted reach and transfers in individuals with tetraplegia: towards a solution.

The purpose of this study was to investigate the influence of a prototype trunk orthosis to assist an individual with tetraplegia. A single case study (26 year old male, C5 motor complete) using an interrupted time series analysis was conducted to investigate the individual's ability to reach, forward and laterally, and transfer with and without the orthosis. All tasks were performed on an AMTI force platform in the long sitting position, with landmarks of the trunk and limbs recorded using Peak Performances Technologies motion analysis system. After a familiarisation period ten trials were attempted for each phase of the analysis. With the orthosis the subject altered the sitting posture and significantly (F = 9.55, P = 0.003) increased the distance the subject was able to reach. The median frequency of the centre of pressure (COP) displacement during the reaching task was not significantly altered. The ability to displace the COP when attempting to transfer increased from 16.0 (+/-3.4 cm) to 19.6 (+/-2.5 cm), however, this was not statistically significant. The likely user population, the overall functional benefits, the compliance of the users and possible modifications to the device to facilitate use with functional electrical stimulation are all possible directions for future research.

Activities of Daily Living↗
PubMed1996

Transfer movement strategies of individuals with spinal cord injuries.

The ability to transfer in tetraplegia is a focal point of rehabilitation. Many factors have been associated with independence in transferring, yet the majority of these are anecdotal reports. The purpose of this paper is to report preliminary findings of the study of movement strategies of individuals with spinal cord injury attempting a long sitting transfer. Analyses were made from the lateral and posterior views. Pattern recognition techniques show two distinct movement strategies in both views. These were a lift and forward flexion technique from the lateral perspective and a translatory and rotatory technique when viewed from behind. It would seem that the posterior view provides more discriminative information. It is recommended that intervention techniques, such as Functional Electrical Stimulation or orthotic devices be developed within fundamental motion analysis constructs to optimize functional outcome.

Adult↗
PubMedDate not supplied

The effect of body position on bioelectrical resistance in individuals with spinal cord injury.

The purpose of this study was to determine the effect of four different body positions on the resistance of the human body as assessed by Biodynamics Model 310 Body Composition Analyzer in a healthy population (Group A, n = 69) and long-term spinal cord injured (Group B, n = 13). Group A were tested in four body positions: supine, half-lying, standing and sitting in a wheelchair, while Group B were tested in supine and sitting positions. Testing order was randomized. A one-way repeated measures analysis of variance and a paired t-test demonstrated significant differences between position (p < 0.0001, Group A; p < 0.01, Group B respectively). In both groups, the greatest reduction in resistance was demonstrated for the sitting position. These differences were similar for both groups, as demonstrated by covariant analysis. Regression analysis demonstrated that supine resistance can be accurately predicted (R2 = 0.98) from assessments in a wheelchair. Such data transformations may be indicated where supine positioning is problematic or when wheelchair assessment procedures are more appropriate.

Adult↗