THE BATH AS METROLOGY INDEX (BASMI)
(Jenkinson et al, 1994)

In considering metrology, the aim of the research team was

“to determine the minimum number of clinically appropriate measurements that assess accurately axial status and from these derive a metrology index (BASMI) to define clinically significant changes in spinal movement.”
(Jenkinson et al, 1994, p1694).

Axial status was regarded as cervical, dorsal and lumbar spine, hips and pelvic soft tissue.

Following a literature review, 5 simple clinical measurements were included in the index:

1. cervical rotation
2. tragus to wall distance
3. lumbar side flexion
4. modified Schober’s
5. intermalleolar distance

For cervical rotation, lumbar side flexion and tragus to wall, a mean of the left and right measurements are taken. A guide in how to obtain these measurements is given in table one on page 8. There are two tables available for calculating BASMI scores from these measurements; these are explained on pages 9 & 10 of this booklet. The higher the BASMI score the more severe the patient’s limitation of movement due to their AS.

By applying a similar scoring system to the original 20-measurement metrology index, the research team was able to compare the two indices. A statistically significant correlation (p<0.001) between the BASMI and the 20-measurement index was shown on 2 occasions (Jenkinson et al, 1994). At the same level of significance (p<0.001), the BASMI also proved to be accurate and reproducible for both inter- and intra- observer variability (Jenkinson et al, 1994).

With a sample of 56 patients undergoing 3 weeks inpatient treatment, the sensitivity of the index to change was found to be significant (p<0.01) regardless of the disease severity (Jenkinson et al, 1994). The mean improvement in measurements was 30% in 71% of the patients. Unfortunately this was not compared with the original 20-measurement index.

These results show that the BASMI is comparable with the original 20 measurements, it is accurate and reproducible, and it is sensitive to change. The BASMI is also quick and easy to apply – taking only 7 minutes.

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Bath Indices Index...

1.	Bath Indices Index
2.	Introduction
3.	The Bath As Metrology Index (BASMI)
4.	The Bath As Functional Index (BASFI)
5.	The Bath As Disease Activity Index (BASDAI)
6.	The Bath As Patient Global Score (BAS-G)
7.	Table One: A Guide to Obtaining the BASMI Measurements
8.	Tables two and three: Calculating the scores for each of the BASMI measurements
9.	The Bath Ankylosing Spondylitis Functional Index (BASFI)
10.	The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI)
11.	The Bath Ankylosing Spondylitis Global Score (BAS-G)
12.	References
13.	Bibliography

 

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