A decrease in mechanical pressure pain thresholds, particularly over pre-designated tender points, is one of the defining characteristics of fibromyalgia syndrome (FS); however, changes in thermal pain sensitivity have not been investigated. The present study examined heat pain thresholds and cerebral event-related potentials following CO2 laser stimulation in 10 subjects with FS and 10 age-matched control volunteers. The results indicate that patients with FS exhibit a significant reduction in heat pain threshold when tested on the dorsal surface of the hand. In accordance with previous research, we also found a decrease in mechanical pain threshold over pre-designated tender points and at control sites as well as a significantly larger mechanically induced neurogenic flare response. These measures were highly correlated with thermal pain threshold even though different anatomical sites were stimulated. Hence, it seems likely that FS patients display a multimodal change in pain sensitivity which is generalized rather than anatomically restricted. Patients with FS also displayed a significant increase in the peak-to-peak amplitude of the cerebral potential evoked by CO2 laser stimulation at pain threshold intensity and 1.5 times pain threshold intensity. These findings suggest a greater activation of central nervous system (CNS) pathways following noxious input. Putative explanations for the increased CNS response are discussed, including mechanisms of peripheral nociceptor sensitization, altered CNS function and the role of psychological factors.

Objective: To test the reliability, validity and utility of an "up-timer", an automated device to measure time spent standing and walking.Design: Repeat measurement of mobility one week apart in a convenience sample. Setting: Hostel and nursing homes in Melbourne.Participants: 26 hostel and 24 nursing home residents (aged 70-99 years) participated. They were mobile, with or without the use of walking aids or personal assistance. Outcome measures:"Up-time" (measured with the up-timer); functional activity (measured with the Barthel Index, Functional Independence Measure, Timed Up & Go, and Human Activity Profile); and disability (measured by the Rapid Disability Rating Scale). Results:The test-retest reliability of the up-timer was high (Pearson's r=0.84; P<0.001). Pearson's correlation between the up-timer results and results of functional and disability measures ranged from r=0.47 to r=0.55. The functional measures correlated more highly among themselves (r=0.79 to r=0.92). The performance-based Timed Up & Go test had moderate levels of correlation with both the up-timer and the functional measures. Use of the device was well accepted by both participants and staff. Conclusions:The up-timer is a practical, objective and reliable means of measuring mobility. The useful information it provides is different from, but overlaps with, that obtained from subjective observation or self report. It will complement existing subjective and performance-based measures of activity and mobility.

Objective measurements of time spent standing or walking would be of benefit in assessing response to therapy. We have tested a device consisting of a mercury tilt switch attached to an electronic counter to measure time spent upright. Eleven subjects, six male and five female age 67-88 years (mean 76 years) undergoing rehabilitation were studied. Diagnoses included: Parkinson's disease, dementia, stroke and femoral fracture. The device was fitted with the tilt switch on the lateral aspect of thigh. Measurements compared stopwatch readings made by an observer and the device. Study periods were of one to three hours. There was excellent correlation between stopwatch and device measurements of time spent standing (t = 0.994; p < 0.001). The device functioned well during physiotherapy and ward activities although measurements were inaccurate when subjects used an exercise bicycle or climbed steps greater than 20 cm in height. The device should prove useful for monitoring activity and response to mobilization therapy.

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