We argue that the experimental data provide evidence that hypnotic analgesia is an active inhibitory process that operates to reallocate thalamocortical activities as evidenced in our rCBF (Crawford et al., 1993), ERP (Crawford et al., 1998; other papers; AND numerous ones in the lit.), fMRI (Crawford et al., 1998), ERP (Crawford et al., 1998; other papers; AND numerous ones in the lit); and EEG (from Chen, Karlin, and my labs). I am most pleased to see Rainville using PET to replicate and extend our research with our prior rCBF and fMRI studies. There is a paper in press in the European J. of Pain from Mats Fredrikson's PET lab that show similar changes in fibromyalgia patients. These inhibitory processes are far reaching as exemplified by work that demonstrates hypnotic analgesia may extend as far as spinal cord antinociceptive mechanisms as evidenced by reductions in brief latency (Hagbarth & Finer, 1963) and R-III amplitude (Kiernan, Dane, Phillips, & Price, 1995) of spinal reflexes (for an exception, see Santarcangelo, Busse, & Carli, 1989). A recent study in PAIN from cooperative research between Carli's lab in Sienna, Italy, and a French group shows either increased or decreased spinal reflex changes in subjects experiencing complete hypnotic analgesia; I am not sure I referenced it, so here it is:
Danziger, N., Fournier, E., Bouhassira, D., Michaud, D., De Broucker, T., Santacangelo, E., Carli, G., Chertock, L., & Willer, J. C. (1998). Different strategies of modulation can be operative during hypnotic analgesia: a neurophysiological study. Pain, 75, 85-92.
We have not seen negative side effects from our experimental research. But we see positive side effects. The clinical literature on the use of hypnotic analgesia with chronic and acute pain patients demonstrates over and over that the successful use of hypnotic analgesia leads to increased self-efficacy and wellbeing of the whole individual. For instance, with a group of adults with chronic low back pain, we found the teaching of experimental pain control (cold pressor and electrical stimulation) was highly effective. The majority were surprisingly moderately to highly hypnotizable. As we report in the Int. J. of Clinical and Experimental Hypnosis special issue on chronic pain (Jan. 1998; also see Oct. 1997 issue as this is a two-part special issue):
"Participating in an experimental study involving the learning of control over experimental pain resulted in transfer of the control to experienced low back pain as well as improved psychological well-being in daily living. Pain experienced at the time of arrival at the experiment decreased significantly. Individuals with more pain tend to report poorer sleep quality and more awakenings during the night (e.g., Affleck, Urrows, Tennen, Higgins, & Abeles, 1996). Overall, our participants reported significant enhancements in sleep quality, as reflected by reduced time to fall asleep, over the experimental period. Similarly, self-reported depression reduced significantly and psychological health increased significantly. Finally, use of medications reduced significantly.
"The experiment demonstrates the importance of developing self-efficacy through the learning of experimental pain control and the understanding of one's own attentional and disattentional abilities. Our data provide experimental support to Brown and Fromm's (1987) introduction of experimental pain control as a first step in enhancing self-efficacy in chronic pain management. Furthermore, it argues for the early introduction of behavioral techniques such as hypnosis and relaxation before the development of chronic pain (Crawford, 1995a,b). Already our experimental pain training approach using the cold pressor test is being used in clinical settings in the United States (e.g., Holroyd, 1996) and Europe (P. Alden, personal communication, October 1996)."
Dependent upon the type of clinical pain and whether it is important to the patient to know if the pain is present or not, some clinicians (e.g., Craselneck) will provide suggestions of reduction but not elimination of pain. In other words, a little bit of pain is sometimes important to have.
You ask: "Are any other activities from the area also affected and is pain from other areas received nevertheless?" This is a very intriguing and provocative two-part question. And needs further investigation! The elimination of pain can be localized or more general. Pain from other areas may be perceived even though pain to the localized area is not. Furthermore, we have observed individuals with no sensation of pain or distress actively move and observe the area which is hypnotically anesthesized and maintain the anesthesia. Some years ago Martin Orne and I consulted on a documentary on hypnosis -- there is a anesthesiologist from UCLA Medical School who placed a sterilized needle through part of his hand, then moves and comments on it, but feels no sensations of pain or distress.
With many thanks, Harry!