Reliability and Validity of Muscle Palpation as an indicator of Subluxation in the Upper Cervical Spine
Joe Donofrio*, Nick Spano%, and Ed Owens*
* Sherman College of Straight Chiropractic
% Private Practice Canton, Pennsylvania
Proposal approved by the Sherman College Research Review Committee May 5, 1999
a. Specific Aims
Sherman College is engaged in research to develop objective measures of vertebral subluxation. Muscle palpation is a technique taught in the curriculum and used routinely in the health center, but has not been well validated as a subluxation measure. The specific aims of this study will be to:
1. test the intra- and inter-examiner reliability of muscle palpation by carrying out cross comparisons of results gained from palpation of patients in the health center.
2. test the validity of muscle palpation by testing the effects of adjustment on palpation findings.
We plan to use three recently trained palpators as examiners in the study and have them assess each patient at least twice. In addition, some patients will be adjusted between assessments to test the hypothesis that the assessment should be able to detect changes in muscle activity related to subluxation. Assessors will be blindfolded so that they will not know which patient is being palpated, or which patients have been adjusted.
b. Background and Significance
Three different palpatory methods have been traditionally used by chiropractors as indicators of the need for chiropractic adjustment: static palpation of vertebral alignment and tenderness, motion palpation for passive movement characteristics and muscle palpation to detect muscle tone imbalances. Of these, motion palpation (MP) has been the most frequently studied. While MP seems to have good face validity, it is considered to have limited objectivity. Keating performed a meta-analysis of the available literature on MP in 1989 and concluded that no strong claims for the objectivity of lumbar motion palpation could be made at that time (1). Studies of MP reviewed by Keating showed very little reliability, a limited number of examiners, and overreliance on asymptomatic students as palpatory subjects.
An interesting finding from reliability studies is that while inter-examiner reliability is typically low, intra-examiner agreement is generally good, i.e. assessors often agree with their own measures. Breen suggests that some of the error can be accounted for by noting that examiners may have simply mis-named the involved segment (2). Panzer came to similar conclusions in a more recent review of the motion palpation literature, and offered the suggestion that improved standardization of palpatory techniques be carried out (3).
The other forms of palpation used by chiropractors also appear to have good face validity, i.e. they make good sense, but there are few if any reports on their objectivity. Without demonstrated reliability, we cannot claim that a method is objective or valid. However, surveys of chiropractors have shown that these methods are in common use and are relied on for making clinical decisions related to patient care (3).
A specific type of muscle palpation technique is taught at Sherman College as one of the methods used to detect subluxation. A similar method, Advanced Muscle Palpation (AMP), is taught by Dr. Nick Spano, who learned the technique at ADIO Institute of Straight Chiropractic from Dr. Harry Shepherd (4). AMP has been the subject of one validity study in which listings from palpation were compared to x-ray findings using the Grostic Procedure of upper cervical x-ray analysis (5). Since only one palpator was used in that study, reliability could not be confirmed, however, the almost perfect concordance between the methods is very encouraging.
While the reliability of AMP has not been studied before, it should still be possible to learn from the mistakes of past studies of motion palpation in developing this study. In particular, this study has been designed to:
In addition to reliability testing, there will be a test of the validity of muscle palpation, i.e. to determine whether muscle palpation really detects the need for adjustment. If a percentage of the patients are adjusted between assessments, and assessors are blinded to that occurrence, then re-assessment should show a clearing of the previously detected muscle findings only in adjusted patients. Hence, a significant degree of clearing of indicators after the adjustment would be strong evidence that the palpation technique is a sensitive indicator of the need for adjustment.
c. Research Design and Methods
Assessor training. Dr. Nick Spano is scheduled to give a four-hour training seminar on the AMP technique at the Lyceum on May 27, 1999. He will be able to double check trainee's findings during the seminar and can pick examiners from his class that show an aptitude for the technique. Three of the best palpators from the class will be selected as assessors in the study. Hence, the study will be conducted on either May 27th or May 28th, while the examiners and Dr. Spano are still in town and freshly trained.
Subject selection. Subjects will be drawn from the new patient population that will be entering the health center during the week of May 24-28. A consent form will be signed and patients will be asked to fill out the SF-36 and Self-Rated Wellness Surveys. Patients will be assessed using the usual elements of the Sherman College pattern analysis, including x-rays, paraspinal thermographic scans, leg checks and palpation performed by their student interns. The patients will not be adjusted prior to the experiment. Any subject who is found on initial exam to be ineligible to receive chiropractic adjustments, according to criteria established in the health center, will be excused from the study. It is hoped that as many as 40 subjects can be enrolled. Student Interns will be sought in the coming weeks to help us by scheduling new patients for the week of the study.
Initial Palpation. On the day of the study, patients will be scheduled to come to the health center in the morning or afternoon, depending on the availability of the examiners. The assessors will be blindfolded and waiting in separate, nonadjacent rooms in the health center. A student intern will also be in the room to act as a data recorder for the blindfolded assessor. Patients will be ushered into the room and positioned supine on the adjusting bench. The palpator will examine the patient using the technique as taught by Dr. Spano and report the findings to the data recorder. The patient will then be ushered back to the waiting room to rest for 5 minutes before being ushered to another room for assessment.
It is possible that repeated probing of the muscles of the neck could result in a challenge to the patient that could change the readings. For that reason, one fourth of the patients will be allowed to rest for twenty minutes after the initial palpation, and then will be repalpated only by the same doctor that performed the initial assessment.
Adjustment Procedure. After all three doctors have palpated the patients, the palpation results as well as initial pattern analyses will be used to determine if the patient is in need of an adjustment. (It is anticipated that most patients will need adjustment.) Those patients that can be adjusted will be randomly assigned to an adjustment or a control group. (Coin toss, or random number table based on patient ID number to assure 50% of the patients are adjusted.) Dr. Donofrio will serve as the adjuster and will perform his own palpatory assessment to determine the listing for the adjustment. X-rays and pattern findings will be provided to him as well to help guide his decision. If there is a clear discrepancy between the listing arrived at with palpation, and the listing from prior x-ray analysis, then the patient will not be adjusted. He will perform an adjustment intended to clear the subluxation indicators
The patient will be post checked by another doctor, using the complete Sherman protocol, then allowed to rest for 10 minutes. After the resting period, patients will be returned to the waiting room in preparation for the final palpation examination.
Patients that were not selected for adjustment will be asked to stay in the waiting room for 20 minutes before commencing their second palpation examination.
Second Palpation. Patients in the waiting room will follow the same procedure again, being ushered to assessors in the examination room for their second palpation. There will be no communication with the assessors that might identify the patient or whether they had been adjusted or not.
Data Analysis. Palpation data sheets will be collated by patient and the data entered into a spreadsheet for data analysis. The AMP procedure results in indications of muscle loading in individual muscles, as well as an overall listing derived from that information. Cohen's Kappa will be calculated to test the agreement between listings derived by different assessments, both between doctors and among individual doctors.
Descriptive statistics on the incidence of findings will be performed, and there will be cross correlation possible between other clinical pattern findings and changes with adjustment, as well.
d. Literature Cited