Whole-Body Vibration Within Specified Frequency Range May Provide Pain Relief

DENTON, Tex-Music has long been used, albeit unscientifically,to relax patients in an effort to relieve pain. Now, a researcherfrom the University of North Texas College of Music is attemptingan approach to music therapy that involves vibration and appearsto have a neurophysiologic mechanism of action.

In his poster presentation at the 8th World Congress on Pain,Kris S. Chesky, PhD, said that the technique involves music listeningfor psychological effect and, for physiological effect, music-generatedwhole-body vibration, with the amplitude and frequency of thevibrations controlled and measured via a device called the MusicVibration Table.

"Animal studies suggest that vibration above 60 Hz has thepotential to decrease the amount of processing in the spinal cordof pain stimuli, an effect that is mediated chemically throughthe neural transmitter adenosine," Dr. Chesky said.

The key is the Pacinian corpuscle, a large vibration-sensitivemechanoreceptor located throughout the subcutaneous and connectivetissues surrounding visceral organs and joints. This corpusclestarts to react to frequencies of 60 Hz and above. "Belowthat frequency, a different receptor is responding, so frequenciesbelow 60 Hz can be used as controls in studies of the vibrationtable," he said.

Music is not essential for vibration-induced analgesia, as longas the levels of vibration are in the 60 to 300 Hz frequency rangeat amplitudes of less than 100 µm at 100 Hz. However, Dr.Chesky believes its use is important because it provides variationto the vibration. This, he says, can decrease patient fatigueand habituation of Pacinian corpuscle processing, while also makingthe vibration meaningful to the patient.

Dr. Chesky's vibration table has been tested in a randomized,double-blind, placebo-controlled study in fibromyalgia patientsat the University of Texas Health Science Center at San Antonio.Results were favorable, and the study has been accepted for publicationin the Journal of Musculoskeletal Pain.

The technique has also been used on an on-call basis to help relievepain in children in sickle cell crisis. Dr. Chesky emphasizedthe need for more rigorous controlled clinical trials of the technique.

An ongoing pilot project at Cooks Fort Worth Children's MedicalCenter involves a new strategy to use vibration prior to surgery."Our assumption was that if we established the central stateassociated with vibration-induced analgesia just before surgery,it might have some preemptive analgesic value," Dr. Cheskysaid.

Research suggests that surgical trauma causes the neurons to becomemore sensitive to incoming pain signals, while vibration-inducedchanges cause them to be less sensitive to such signals. "Ifthe neurons are less sensitive prior to surgery, they may alsobe less sensitive after surgery, thus reducing postoperative pain,"he said.

The researchers have just completed preemptive and postoperativeinterventions in six young girls undergoing spinal fusion surgeryfor scoliosis, "an incredibly painful 7-hour operation,"Dr. Chesky said.

For 40 minutes prior to surgery, the patient is bathed in vibrationgenerated by the music she has chosen to hear. The vibration continuesas the patient is transferred to the operating suite. "Wetry to continue the stimulation as long as possible up to thepoint of incision," he said.

The first day after surgery, a music therapist brings music forthe patient to listen to and reviews with her various music relaxationtechniques; the vibration table is brought in when the patientasks for it (usually about 3 days after surgery when the morphinedosage is being reduced).

Preliminary data are showing good results, Dr. Chesky said, basedon pre- and post-vibration pain scores after surgery, and on unstructuredinterviews with the patients.