Changes in somatic sensitivity during transcutaneous electrical analgesia.

Patients with chronic pain in one limb, who experienced pain reduction with transcutaneous neurostimulation, were examined for sensory perception in that limb before and during electrical analgesia. Contralateral limbs and normal subjects served as controls. Sensory stimuli were quantified, a range of stimuli were presented and data were analyzed according to sensory decision theory. Results showed that, compared to controls, painful limbs show considerable impairment in sensory sensitivity. With transcutaneous neurostimulation, however, sensitivity is improved towards normal, whereas electrical stimulation slightly impairs perception in normal limbs. These results suggest that electrical analgesia involves both peripheral small-fiber blockade and large-fiber stimulation; the latter is more noticeable in the normal limb, but the former effect is predominant when pain reduction occurs in a painful limb.

The pain ward follow-up analyses.

Two-year and 3-year follow-up analyses show that those who did not receive surgery for pain relief did as well as those who did receive such surgery during their stay, both groups showing consistently lower pain levels and analgesic intake than on admission, while activity levels progressively increased. The surgical patients were more likely to be readmitted for their pain problem than were the others, whereas the others were more likely to be readmitted for other medical problems.

On the sensitivity of the tourniquet pain test.

Twenty-four chronic pain patients were given, on each of 4 successive days, oral doses of 60 mg morphine, 60 mg codeine, 600 mg aspirin and placebo, using a double-blind counterbalanced design. Two hours after ingestion, subjective pain estimates and tourniquet pain scores were obtained. Variability of the tourniquet pain scores was too great for differences in response to the analgesics to be significant. However, differences in pain estimates were also too small to discriminate among the drugs, and the lack of sensitivity may be a function of pain chronicity. The tourniquet techniques will continue to be useful until there is a purely objective measure of the severity of clinical pain.

Transcutaneous electrical analgesia: a follow-up analysis.

One year follow-up data are analyzed for the effects of using transcutaneous neurostimulators on patients with chronic benign pain. Those who have successful surgery for pain relief have lower pain and analgesic intake levels than those who supplement their surgery with neurostimulation. Those who do not receive surgery for pain but use neurostimulators have greatly increased activity levels than those who do not use these devices. The neurostimulators lower the clinical pain level component of the tourniquet test score for non-surgery patients to a degree comparable to that of patients with successful surgical outcomes, but maximum pain tolerance is not significantly altered. This supports the hypothesis that the analgesic effect is primarily a peripheral one.

Personality changes associated with reduction of pain.

Of 113 patients treated in a 2-year period, for whom complete data were available, 29 who received surgery for pain relief were compared with 84 who did not, both groups receiving psychological treatment and rehabilitation. Using an analysis of covariance to eliminate pre-treatment differences, the surgery patients showed significantly greater reductions on the MMPI Hysteria and Hypomania scales, and on the invalidism scale of a Health Index, and this was associated with a significantly greater reduction of pain. These differences obtained despite a greater increase in activity levels by the non-surgery patients at the time of testing. The results support the hypothesis that the neuroticism associated with chronic pain is the result of it, and may be reversible when the pain is reduced or abolished.