337(standard clinical test used to diagnose carpal tunnel syndrome), (4) loss of 2-point
discrimination (feeling 2 separate points touched on the skin), (5) numbness at night
that wakes the patient up, and (6) a positive Tinel’s sign (another standard clinical test
used to diagnose carpal tunnel syndrome). The CTS-6 is scored with conventional
scoring (similar to that used for the 11-item symptom severity scale); each item was
scored on a scale of 1 (no symptom) to 5 (most severe symptom). For each patient, a
CTS-6 score was calculated as the mean of the items answered by the patient, with
only 1 missing item response allowed, and would thus range from 1 (best) to 5 (worst).
The original study carried out by Atroshi et al. [ 39 ] revealed that the 6-item CTS
symptoms scale demonstrated good internal consistency, test–retest reliability, and
validity compared with the 11-item symptom severity scale and did not exhibit dif-
ferential item functioning with regard to gender. In another study [ 45 ], the CTS-6
was reported to be highly responsive to change in symptoms, and has been recom-
mended by the authors (who originally developed the questionnaire) as a tool for
evaluating primary and secondary outcomes measures in clinical trials studying car-
pal tunnel syndrome. Because the CTS-6 has previously shown good agreement
with the 11-item symptom severity score, is scored on similar scale, and the fact the
CTS-6 is shorter with improved layout, the authors suggested using the CTS-6 as an
alternative to the 11-item symptom severity scale. John et al. [ 44 ] compared changes
in the 6-item CTS symptoms scale and portable nerve conduction study parameters
as outcome tools in CTS patients treated with steroid injections. There was a statis-
tically signifi cant difference between the CTS-6 scores before and after injection.
There were also statistically signifi cant changes in fi ve of the nerve conduction test-
ing parameters. However, none of the correlations between the CTS-6 and the nerve
conduction study parameters were statistically signifi cant.
Patient Evaluation Measure ( PEM )
The questionnaire, developed in 1995 by Macey et al. [ 46 ], consists of three
domains: patients’ opinion on delivery of care, hand health profi le, and overall
assessment. The instrument has a total of 18 items that are scored using a 7-point
scale. In all scales, low scores indicate positive outcomes. The authors did not report
on item generation and item reduction. Similarly, there was no report on other
aspects of the instrument development. The instrument may be self-, interview-, or
telephone-administered.
Support for construct validity was revealed in a study carried out by Forward
et al. [ 47 ], which reported signifi cant correlation between the objective measures
(PEM scores) and the subjective measures (e.g., increased grip strength). Convergent
validity was demonstrated by strong signifi cant correlations between PEM and
DASH scores both pre- and postoperatively in CTS patients [ 48 ]. In concordance,
there was a signifi cant reduction in PEM scores in a sample of 97 patients undergo-
ing carpal tunnel decompression surgery. This was recorded at 6 weeks as well as 6
months postsurgery.
13 PROMs for Carpal Tunnel Syndrome