Water flow modulates the response of coral reef communities to ocean acidification.

By the end of the century coral reefs likely will be affected negatively by ocean acidification (OA), but both the effects of OA on coral communities and the crossed effects of OA with other physical environmental variables are lacking. One of the least considered physical parameters is water flow, which is surprising considering its strong role in modulating the physiology of reef organisms and communities. In the present study, the effects of flow were tested on coral reef communities maintained in outdoor flumes under ambient pCO2 and high pCO2 (1300 µatm). Net calcification of coral communities, including sediments, was affected by both flow and pCO2 with calcification correlated positively with flow under both pCO2 treatments. The effect of flow was less evident for sediments where dissolution exceeded precipitation of calcium carbonate under all flow speeds at high pCO2. For corals and calcifying algae there was a strong flow effect, particularly at high pCO2 where positive net calcification was maintained at night in the high flow treatment. Our results demonstrate the importance of water flow in modulating the coral reef community response to OA and highlight the need to consider this parameter when assessing the effects of OA on coral reefs.

Effect of chiropractic intervention on small scoliotic curves in younger subjects: a time-series cohort design.

BACKGROUND: Chiropractors have long claimed to affect scoliotic curves, and case studies abound reporting on successful outcomes. No clinical trials exist, however, that evaluate chiropractic's effectiveness in the management of scoliotic curves. OBJECTIVE: To assess the effectiveness of chiropractic intervention in the management of adolescent idiopathic scoliosis in curves less than 20 degrees. DESIGN: Cohort time-series trial with all subjects electing chiropractic care. Entry-level Cobb angle was compared with postmanagement curve. METHODS: Forty-two subjects completed the program of chiropractic intervention. Age range at entry was 6 to 12 years, and patients were included if their entry-level x-ray films revealed curves of 6 degrees to 20 degrees. Participants had adjustments performed for 1 year before follow-up. Full-spine osseous adjustments were the major form of intervention, but heel lifts and postural and lifestyle counseling were used as well. RESULTS: There was no discernable effect on the severity of the curves as a function of age, initial curve severity, frequency of care, or attending physician. CONCLUSION: Full-spine chiropractic adjustments with heel lifts and postural and lifestyle counseling are not effective in reducing the severity of scoliotic curves.

Errors in precise examiner head placement during cervical range-of-motion measurements.

OBJECTIVE: To quantify errors associated with examiner-assisted neutral head placement in cervical range of motion measurements in normal subjects and to investigate the influence of these errors on range of motion measurements. DESIGN: Repeated-measures design with cervical range of motion and errors in placement measured in 20 volunteers with no symptoms with the OSI CA-6000. METHODS: Examiner placement of head position was achieved with inclinometers and triangulation. Subjects estimated pain experienced during measurements with numeric pain scales. Angular data around 3 axes were analyzed with descriptive statistics. Possible correlations between errors and other variables were investigated. RESULTS: Drift, defined as displacement from original head positioning at first data acquisition and before initiation of motion, was negligible (+/-0.8 degrees ). Standard errors in neutral head placement ranged from 1.0 degrees in axial rotation to 3.2 degrees in flexion/extension. Within-trial variability of neutral position did not correlate with between-trial differences in ranges of motion. CONCLUSION: Head position errors were not the primary sources of variability for between-trial measurements of cervical range of motion. The largest errors were in flexion/extension, and least, in axial rotation. Neutral position errors up to approximately 5 degrees for lateral bending, 3 degrees for rotation, and 9 degrees for flexion and extension fall within 95% CI and are the recommended lower limits for significant changes in clinical settings.

Standardized initial head position in cervical range-of-motion assessment: reliability and error analysis.

OBJECTIVE: To assess the clinical reliability and precision of the OSI CA-6000 Spinal Motion Analyzer for measurement of range of motion in cervical spines of pain-free subjects by using a novel procedure designed to minimize variability and quantitatively evaluate sources of errors. METHODS: Twenty asymptomatic volunteer subjects were evaluated twice by each of two trained examiners in one session. Subject position was carefully standardized. Rotation, lateral bending, and flexion-extension were evaluated in repeated movements (cycles) from extreme to extreme. ANALYSIS: Descriptive statistics and reliability coefficients (interclass correlation coefficients [ICCs]) were calculated for all full- and half-cycle motions. Possible sources of systematic errors were evaluated, and random errors were estimated. RESULTS: ICCs indicate that the instrument performs very reliably for rotation and lateral bending (0.93-0.97) and acceptably for flexion-extension (0.75-0.93) measurements. Differences in instrument placement, subject posture, or both in different trials correlate neither with differences in measured values nor with variances. Within-trial errors did not correlate with ranges of motion. Standardizing head position resulted in increases in reliability of from 3% to 15% for axial rotation and lateral bending but actually decreased the ICCs for flexion-extension (up to 14%) compared with data collected under a less-stringent protocol. Errors in clinical use are estimated at 4.5 degrees. CONCLUSIONS: By using our modifications to the accessories and standardization of subject position, the CA-6000 is a highly precise and reliable instrument for measuring active cervical motion about the 3 Cartesian axes. Individuals can repeat the same patterns of motion in sequential trials on the same day with very little variation. Ease of repetitious measurement without examiner intervention contributes to the instrument's ability to obtain highly reliable data. Changes in instrument placement or subject body posture between trials do not give rise to systematic errors. Design of the instrument for flexion-extension could be improved.

Meta-analysis of normative cervical motion.

STUDY DESIGN: Meta-analysis of normative cervical range of motion literature performed by applying summary statistics to range of motion and reliability values reported among studies. OBJECTIVES: To identify reliable and valid methods for measuring active and passive cervical range of motion and to estimate normative values. SUMMARY OF BACKGROUND DATA: Range of motion studies use a variety of measuring instruments and statistical analyses, making it difficult to select the most suitable instruments, procedures, and normative values for clinical application. Reviews of the literature, being limited in scope, have not quantitatively synthesized the literature. METHODS: Range of motion and reliability data were grouped by technology and types of motion, then summarized by deriving means and variabilities. Clinical validity was assessed by examining discrepancies, variabilities, and correlations. Change in range of motion as a function of age was determined by comparing range of motion ratios (fourth:third and seventh:third decades). RESULTS: Nine technologies were identified. Overall, passive motion was greater than active motion, and range of motion decreased as age increased, with women exhibiting greater range of motion than men. Variations within each technology were as large as or larger than those between technologies, indicating that clinical procedures are as important as the accuracy and precision of the technology itself. Reliability has not been adequately tested for the majority of technologies. CONCLUSIONS: Clinical procedures appear to be as important as accuracy and precision in determining the reported range of motion values. Further research is needed to establish a gold standard for normative values and to identify an instrument that is reliable for all motions.

Clinical validity and stability of active and passive cervical range of motion with regard to total and unilateral uniplanar motion.

STUDY DESIGN: A study of inter- and intra-examiner reliability and clinical validity using two instruments for assessment of spinal range of motion in healthy individuals. OBJECTIVE: To assess the clinical validity, stability, and normative values for active and passive cervical range of motion as measured by the CA-6000 (Orthopedic Systems Inc., Union City, CA), an electrogoniometer. SUMMARY OF BACKGROUND DATA: The authors' early trials with the electrogoniometer yielded values that differed substantially from those in other reports. The authors sought to resolve those discrepancies and understand their sources. METHODS: Axial rotations along the transverse, coronal, and frontal planes were measured as half-cycles (i.e., left-right or flexion-extension) that were repeated seven times per trial. Test-retest data were collected on the same healthy individuals for active and passive motion using men and women aged 20-39 years. For validity, simultaneous digital dual inclinometry and electrogoniometry were performed twice over a 1-week interval. In addition, a bench test was performed for validation of axial rotation. RESULTS: Clinical reliability of the CA-6000 was high for inter- and intra-examiner studies of total active motion, and validity was high when compared with that obtained with dual inclinometry. Total range of motion had less between-trial variability than half-cycles, axial rotation and lateral bending measurements had greater reliability than did flexion-extension measurements, and active motion was more reliable than passive motion. CONCLUSION: The CA-6000 provides valid and reliable measures of cervical range of motion. Discrepancies reported elsewhere appear to have arisen from several sources, as discussed in this article.

Application and evaluation of the kappa statistic in the design and interpretation of chiropractic clinical research.

The Kappa statistic (K) is becoming more widely used in chiropractic clinical research. Although the calculation of K is straightforward, assumptions made regarding the acquisition and interpretation of data require serious consideration before conclusions regarding the final outcome can be made. Of particular interest is the application of K for the interpretation of validity and reliability. In this regard, I argue against the use of K as a summary statistic. I present here a description of K as a function of observer agreement (P(o)), without which K has little meaning, and show how a knowledge of this function should direct the design and, therefore, the interpretation of chiropractic clinical research. Only when all concerns regarding experimental design are either addressed directly or compensated for in the analysis can interpretations be made regarding validity or reliability. Lacking such attention, K becomes an indicator of experimental design rather than an indicator of validity or reliability.

Behavior and interpretation of the kappa statistic: resolution of the two paradoxes.

Two apparent paradoxes have been identified for the kappa (kappa) statistic: (1) high levels of observer agreement with low kappa values; (2) lack of predictability of changes in kappa with changing marginals. The first paradox is a function of prevalence of the trait in the sample, while the second is related to symmetry of observations in the disagreement categories. While examining the behavior of kappa as a function of the distribution of responses in a contingency table, it was discovered that for any measured level of observer agreement (Po) there are three characteristic values of kappa: kappa max, kappa min, and kappa nor, each of which is a function only of Po. The characteristic values allow an observed kappa (kappa o) to be placed into perspective. By observing symmetry in agreement and disagreement categories, the behavior of kappa is readily understood and predictable. We define symmetry expressions for agreement (SA) and disagreement (SD) in order to represent and quantify these effects. Kappa alone has little interpretive value and we recommend that studies reporting kappa also report Po, SD, and P++ (agreement on the presence of the trait).