Correlations Between Electrically Quantified Pain Degree, Subjectively Assessed Visual Analogue Scale, and the McGill Pain Questionnaire: A Pilot Study.
OBJECTIVE
To evaluate the clinical utility of the electrically calculated quantitative pain degree (QPD) and to correlate it with subjective assessments of pain degree including a visual analogue scale (VAS) and the McGill Pain Questionnaire (MPQ).


METHODS
We recruited 25 patients with low back pain. Of them, 21 patients suffered from low back pain for more than 3 months. The QPD was calculated using the PainVision (PV, PS-2100; Nipro Co., Osaka, Japan). We applied electrodes to the medial forearm of the subjects and the electrical stimulus was amplified sequentially. Minimum perceived current (MPC) and pain equivalent current (PEC) were defined as minimum electrical stimulation that could be sensed by the subject and electrical stimulation that could trigger actual pain itself. To eliminate individual differences, we defined QPD as the following: QPD=PEC-MPC/MPC. We scored pre-treatment QPD three times at admission and post-treatment QPD once at discharge. The VAS, MPQ, and QPD were evaluated and correlations between the scales were analyzed.


RESULTS
Result showed significant test-retest reliability (ICC=0.967, p<0.001) and the correlation between QDP and MPQ was significant (at admission SRCC=0.619 and p=0.001; at discharge SRCC=0.628, p=0.001). However, the correlation between QPD and VAS was not significant (at admission SRCC=0.240, p=0.248; at discharge SRCC=0.289, p=0.161).


CONCLUSIONS
Numerical values measured with PV showed consistent results with repeated calculations. Electrically measured QPD showed an excellent correlation with MPQ but not with VAS. These results demonstrate that PV is a significantly reliable device for quantifying the intensity of low back pain.
Department of Rehabilitation Medicine, Hanyang University College of Medicine, Seoul, Korea.
Junho
J
Kim
Department of Rehabilitation Medicine, Hanyang University College of Medicine, Seoul, Korea.
Kyung Soo
KS
Lee
Department of Rehabilitation Medicine, Hanyang University College of Medicine, Seoul, Korea.
Sang Won
SW
Kong
Department of Rehabilitation Medicine, Hanyang University College of Medicine, Seoul, Korea.
Taikon
T
Kim
Department of Rehabilitation Medicine, Hanyang University College of Medicine, Seoul, Korea.
Mi Jung
MJ
Kim
Department of Rehabilitation Medicine, Hanyang University College of Medicine, Seoul, Korea.
Si-Bog
SB
Park
Department of Rehabilitation Medicine, Hanyang University College of Medicine, Seoul, Korea.
Kyu Hoon
KH
Lee
Low back pain; Pain measurement; Pain threshold