PubMed Health⌕ Search

Biomedical subjects

C G Maher

Publications and source records attributed to C G Maher.

13 recordsLinked to original sources
PubMed2002

Effect of applying different "levels of evidence" criteria on conclusions of Cochrane reviews of interventions for low back pain.

The objective of this study was to examine the consistency of conclusions of Cochrane systematic reviews when different criteria are used to determine levels of evidence. We reanalyzed the data in six Cochrane reviews of conservative treatment of low back pain by applying three additional sets of "levels of evidence" criteria. Overall agreement between the conclusions attained with the different levels of evidence criteria was only "fair" (multirater kappa coefficient 0.33; 95% CI 0.28 to 0.38). For example, the four sets of levels of evidence criteria produced four conclusions on the efficacy of back school: "strong evidence that back schools are effective," "weak evidence," "limited evidence," and "no evidence." Pairwise agreement between the four pooling systems ranged from slight to substantial (kappas ranging from 0.10 to 0.80). Different rules for determining levels of evidence in systematic reviews produce markedly different conclusions on treatment efficacy. Crown

Evidence-Based Medicine↗
PubMed2001

Randomized controlled trial of neural mobilization after spinal surgery.

STUDY DESIGN: Randomized controlled trial with 12-month follow-up. OBJECTIVES: To determine whether the addition of neural mobilization to standard postoperative care improved the outcome of lumbar spinal surgery. SUMMARY OF BACKGROUND DATA: It has been suggested that neural mobilization should be performed after spinal surgery to prevent nerve root adhesions and improve outcome. However, to date, there is no convincing evidence of the value of neural mobilization. METHODS: Eighty-one patients undergoing lumbar discectomy, fusion, or laminectomy at a private hospital in Sydney were randomly allocated to standard postoperative care or standard care plus neural mobilization. Neural mobilization included passive movements and active exercises designed to mobilize the lumbosacral nerve roots and sciatic tract. Primary outcome measures were global perceived effect measured on a 7-point scale, pain measured using visual analogue scales and the McGill Pain Questionnaire, and disability measured with the Quebec Disability Scale. RESULTS: All patients received the treatment as allocated with 12-month follow-up data available for 76 patients (94% of those randomized). There were no statistically significant or clinically significant benefits provided by the neural mobilization treatment for any outcome. CONCLUSIONS: The neural mobilization protocol evaluated in this study did not provide an additional benefit to standard postoperative care for patients undergoing spinal surgery. The authors advocate that this protocol not be used in clinical practice.

Analysis of Variance↗
PubMed2001

Indenter head area and testing frequency effects on posteroanterior lumbar stiffness and subjects' rated comfort.

Although several mechanical devices have been developed to objectively assess posteroanterior (PA) stiffness of the lumbar spine, no standardized testing protocol has been adopted. Two factors that may vary across protocols, and that effect measured stiffness and the comfort of the test subject, are the size of the indenter head used to apply the PA pressure, and indenting frequency. Three variables; PA stiffness, defined as the slope of the stiffness curve (K), the displacement of the indenter at 30N (D30), and rating of perceived comfort, were measured in 36 subjects asymptomatic for low back pain. For each subject nine tests were conducted, using three different indenter head sizes (300mm(2), 720mm(2)and 1564mm(2)) at each of three different testing frequencies (0.25 Hz, 0.5 Hz and 2 Hz). Machine testing with a large indenter head produced a lower K value, an increased D30 value and higher perceived comfort, while a fast testing frequency produced a higher K value and a lower D30 value. An indenter size by frequency interaction showed small indenter heads to be least comfortable at slow speed. The differences found suggest that the indenter head size and the testing frequency should be standardized during mechanical spinal stiffness testing.

Acute Disease↗
PubMed2001

Development of an instrumented couch to measure forces during manual physiotherapy treatment.

This paper reports on an instrumented couch developed to measure the forces applied during posteroanterior (PA) mobilization to the lumbar spine. The couch was evaluated for reliability by applying known weights to the empty couch, while accuracy was investigated by applying weights both to the empty couch and to a human subject lying on the couch. The equipment appears highly reliable when measuring forces in three directions (ICC(2,1); 99% CI=0.99-1.00) and also demonstrates acceptable accuracy; a maximum error of less than 2% being obtained when measuring forces applied to human subjects. The results demonstrate a highly linear relationship (r2=0.99) between the force readings and the known weights. In conclusion, the instrumented couch demonstrates suitable accuracy and reliability for measuring the force applied to a subject during the application of PA mobilization to the lumbar spine.

Beds↗
PubMed2000

PEDro. A database of randomized trials and systematic reviews in physiotherapy.

This paper describes PEDro, the Physiotherapy Evidence Database. PEDro is a web-based database of randomized controlled trials and systematic reviews in physiotherapy. It can be accessed free of charge at http://ptwww.cchs.usyd.edu.au/pedro. The database contains bibliographic details and abstracts of most English-language randomized trials and systematic reviews in physiotherapy, and of many trials and reviews in other languages. Trials on the database are rated on the basis of their methodological quality so that users of the database can quickly identify trials of high quality. Trials and systematic reviews are extensively indexed to facilitate searching. PEDro provides an important information resource to support evidence-based clinical practice.

Databases, Bibliographic↗
PubMed1999

The reliability and validity of the Biering-Sorensen test in asymptomatic subjects and subjects reporting current or previous nonspecific low back pain.

STUDY DESIGN: A reliability study and case-control study were conducted. OBJECTIVES: To determine the reliability and discriminative validity of the Biering-Sorensen test. SUMMARY OF BACKGROUND DATA: A low Biering-Sorensen score has been found to predict who will have nonspecific low back pain. However, the reliability of the test remains controversial, implying that some studies may have produced results that underestimated the magnitude of the predictive validity of this test. METHODS: Two raters measured the time holding a specific position (holding time) of 63 subjects (23 currently experiencing nonspecific low back pain, 20 who had had an episode, and 20 who were asymptomatic) while they performed the Biering-Sorensen test twice, 15 minutes apart. A standardized protocol was followed. Test-retest reliability was evaluated by calculating intra-class correlation coefficients (ICC 1,1), 95% confidence intervals (CI), and standard errors of the measurement (SEM) for the total group and for the subgroups. A three-way analysis of variance was used to determine whether test order, subject gender, or symptom status affected holding time. RESULTS: High reliability indices were obtained for the Biering-Sorensen test in subjects with current nonspecific low back pain (ICC [1,1], 0.88; 95% CI, 0.73-0.95; SEM, 11.6 seconds), in subjects who had had nonspecific low back pain (ICC [1,1], 0.77; 95% CI, 0.52-0.90; SEM, 17.5 seconds), and in asymptomatic subjects (ICC [1,1], 0.83; 95% CI, 0.62-0.93; SEM, 17.4 seconds). Results of an analysis of variance showed that subjects asymptomatic for low back pain had a significantly longer holding time than the other two groups (P < 0.05). CONCLUSIONS: The Biering-Sorensen test provides reliable measures of position-holding time and can discriminate between subjects with and without nonspecific low back pain.

Adult↗
PubMed1999

Plinth padding confounds measures of posteroanterior spinal stiffness.

This study investigated whether the presence of plinth padding influences measured posteroanterior spinal stiffness. Two measures of posteroanterior stiffness, the slope of the loading curve (K) and the displacement at 30 N (D30) were made at three vertebral levels: L3, T12 and T6, on a rigid and a padded plinth in 24 asymptomatic subjects. Analysis of variance demonstrated a significant reduction in K and increase in D30 when measured on the padded compared to the rigid surface and an interaction effect for both the K and D30 measures, indicating that the effect of the padding depends upon the vertebral level tested. The correlations between the padded and unpadded stiffness measures ranged from 0.70 to 0.87. The data from this study suggest that the type of plinth surface needs to be standardised when evaluating PA stiffness.

Adult↗
PubMed1998

Therapists' conceptualization and characterization of the clinical concept of spinal stiffness.

BACKGROUND AND PURPOSE: The clinical concept of spinal stiffness provides one basis for applying spinal manipulation. Because the terms used to describe the perceptual results of manual spinal stiffness testing are poorly defined, the nature and number of attributes contained in the concept remain unclear. This study attempted to clarify the concept of spinal stiffness by examining the relationships among 31 published spinal stiffness descriptors using cluster analysis. SUBJECTS AND METHODS: Each stiffness descriptor was printed on a magnetized rubber strip. Physical therapists in Houston (Tex) and Sydney (New South Wales, Australia) judged the similarity of the stiffness descriptors by arranging them on a board. The squared Euclidean distance between words was calculated, and cluster analysis was performed using Ward's method. RESULTS: Cluster analysis reduced the 31 stiffness descriptors to three superclusters (limited mobility, increased mobility, and viscoelasticity) in both the Houston and Sydney data. CONCLUSION AND DISCUSSION: In a step toward improving the reliability of spinal stiffness judgments, this study has identified the fundamental characteristics of the clinical concept of spinal stiffness. Research is now needed to clearly define these characteristics and then develop protocols that will allow physical therapists to reliably rate these attributes.

Cluster Analysis↗
PubMed1998

An investigation of the reliability and validity of posteroanterior spinal stiffness judgments made using a reference-based protocol.

BACKGROUND AND PURPOSE: The reliability and criterion-related validity of ratings of posteroanterior (PA) spinal stiffness made using reference values for comparison have not been investigated. In this study, mechanical reference stimuli for points on an 11-point rating scale were used to determine whether using a reference scale may be feasible. Subjects. Five different raters took part in 2 studies in which they rated 40 subjects who were asymptomatic for low back pain. METHODS: The interrater reliability of ratings was evaluated with intraclass correlation coefficients (ICCs) and standard errors of the measurement (SEMs). Criterion-related validity was evaluated by correlating judgments of PA spinal stiffness assessed manually with measurements of PA spinal stiffness provided by a mechanical device, the "Stiffness Assessment Machine" (SAM). RESULTS: Although the reliability indices were generally high, with ICCs reaching .77 and with SEMs as low as 0.72 points, the evidence for criterion-related validity (i.e., the ability of the examiner to judge spinal stiffness levels) was not strong, with correlations reaching only .56. CONCLUSIONS AND DISCUSSION: The reference-based protocol allows for more reliable measures of PA stiffness judgments than previous protocols have; however, the human ratings are not highly correlated with the SAM measures. The protocol will have clinical value if judgments made using it are shown to be reliable in clinically relevant subjects and to have validity for clinical management of patients.

Biomechanical Phenomena↗
PubMed1996

Evaluation of a new device for measuring responses to posteroanterior forces in a patient population, Part 1: Reliability testing.

BACKGROUND AND PURPOSE: This study determined the test-retest reliability of measurements of responses to posteroanterior (PA) forces made using a recently developed instrument. SUBJECT: Twenty-two subjects with nonspecific low back pain participated. METHODS: The length of the low- stiffness or "toe" region and the slope of the linear portion of the force-displacement curve were measured on two occasions. Reliability of repeated measurements was evaluated by intraclass correlation coefficients and percentage-of-agreement scores. The presence of a systematic change in the response to PA forces was evaluated by a paired-samples t test. RESULTS: High reliability coefficients were obtained for both indices of the response to PA forces. The t test revealed no systematic change with repeated testing. CONCLUSION AND DISCUSSION: The new device provides highly reliable measurement of the lumbar PA force-displacement relationship and may prove useful in evaluating theories that have suggested a relationship between spinal symptoms and abnormal PA stiffness.

Adult↗
PubMed1996

Stiffness judgments are affected by visual occlusion.

OBJECTIVE: The current protocol for judging posteroanterior (PA) spinal stiffness has been shown to provide unreliable estimates of PA stiffness. It is possible that a failure to standardize therapists' use of vision in the test protocol partly contributes to the disagreement between raters. This study sought to establish whether vision affects stiffness judgments and so needs to be standardized when judging PA stiffness. DESIGN: Perceptual study using a mechanical device to provide stiffness stimuli with physiotherapists and lay people as judges. SETTING: University psychophysics laboratory. INTERVENTIONS: Occlusion of vision via opaque goggles. MAIN OUTCOME MEASURES: Measures of interstimulus discriminability and bias. RESULTS: Occluding vision had no effect on judges' ability to discriminate between stiffness stimuli; however, the same stimuli were judged as significantly stiffer under the visual occlusion condition. CONCLUSION: The data from this study suggest that vision needs to be controlled when using manual tests to judge PA spinal stiffness.

Analysis of Variance↗
PubMedDate not supplied

Number of sampling movements and manual stiffness judgments.

OBJECTIVE: It has been suggested that when using posteroanterior pressure to assess the stiffness of the spine, no more than two or three oscillations should be used. This study sought to examine this clinical impression by investigating the effect of the number of sampling movements on stiffness perception. DESIGN: Perceptual study using a mechanical device to provide stiffness stimuli, with university staff and students as judges. SETTING: University psychophysics laboratory. INTERVENTIONS: In part 1, subjects were directed to sample the stimuli a prescribed number of times (either 1, 2, 3, 4 or 5 pushes), whereas in part 2, subjects were free to choose the number of sampling movements. MAIN OUTCOME MEASURE: Measures of interstimulus discriminability and bias. RESULTS: An inverted-U relationship between the number of directed sampling movements and stiffness discriminability was found, with three cycles providing best discriminability. When subjects were given a choice, most chose to use three cycles. The number of sampling movements had no effect on bias. CONCLUSION: This study confirms the hypothesis under investigation and suggests that therapists will be maximally sensitive when using three testing cycles of posteroanterior pressure to assess stiffness.

Adult↗