Faculty Bibliography

BACKGROUND AND PURPOSE. People with osteoarthritis (OA) of the knee who have pain generally exhibit decreased activity and physical deconditioning. This study investigated the effects of mechanical unweighting on knee pain and exercise responses in people with OA of the knee who have pain. SUBJECTS. Four men and 23 women, with a mean age of 67.9 years (SD = 11.3, range = 50-88) and having a 12-year average duration of knee OA, participated. METHODS. A mechanical unloading device enabled subjects to perform a modified Naughton treadmill exercise test at 0%, 20%, and 40% of body weight support (BWS). Oxygen consumption (VO2), heart rate (HR), and perceived pain were measured during the last minute of each exercise stage. RESULTS. Mechanical unweighting at 20% and 40% BWS decreased the Vo2 and HR responses to treadmill exercise but did not decrease knee pain during walking in this sample. CONCLUSION AND DISCUSSION. These findings indicate that treadmill exercise accompanied by BWS permits recommended training intensities to be obtained in elderly people with OA, but may not provide pain relief in this group

PURPOSE: To examine the effects of lomustine (CCNU), a commonly used nitrosourea, and craniospinal radiation therapy on the subsequent development of restrictive lung disease (RLD) following treatment for malignant brain tumors. PATIENTS AND METHODS: Pulmonary function testing with measurement of lung volume, spirometry, and diffusion capacity was performed in 28 patients who had received CCNU and/or radiation therapy as treatment for a malignant brain tumor. The median age at the time of treatment was 11.4 years (range, 3.9 to 36.7) and radiation therapy was completed 6 months to 11.6 years (median, 2.6 years) before testing. Patients were divided into four groups based on prior therapy. Group 1 received involved-field irradiation and a CCNU-containing chemotherapy regimen (n = 7); group 2, craniospinal irradiation with a boost to the primary tumor site and a CCNU-containing chemotherapy regimen (n = 6); group 3, craniospinal irradiation with a boost to the primary tumor site and a non-CCNU-containing chemotherapy regimen (n = 7); and group 4, craniospinal irradiation with a boost to the primary tumor site without chemotherapy (n = 8). RESULTS: Fourteen patients (50%) had findings consistent with RLD. One of seven patients (14.3%) who received CCNU without spinal irradiation had RLD, whereas 13 of 21 (61.9%) who received spinal irradiation with or without CCNU had RLD (P = .038), including four of eight patients treated with craniospinal irradiation alone. Logistic regression analysis showed that only spinal irradiation was a significant predictor for RLD. Patients who received spinal irradiation were 4.3 times more likely to have RLD than those who did not receive spinal irradiation. CONCLUSION: Spinal irradiation may be a risk factor for the development of RLD

We tested the hypothesis that a distractive stimulus, such as music, introduced during exercise can reduce perception of respiratory effort at any given level of exercise, whereas sensory deprivation increases effort perception. Thirty-six patients with moderate COPD participated in four sessions of symptom-limited exercise. The first session familiarized the subject with the protocol. The other sessions were performed under partial visual isolation while listening to music (M), or to grey noise (GN), or in silence (SIL), presented in randomized order. Subjects graded their respiratory effort using the Borg rating of perceived exertion (RPE) scale. Total exercise time (EXT) and external work (WT) were objective indices of exercise tolerance. EXT was 22% longer with M than with either GN or SIL (p < 0.001), and WT was 44% and 53% greater with M than with GN or SIL, respectively (p < 0.001). These increases occurred at a heart rate that was only a few beats higher than during GN or SIL (104 +/- 3 bpm for M and 101 +/- 3 bpm for GN and SIL), a minimal difference that was statistically significant (p < 0.001). At every level of exercise, perceived exertion with M was lower than for either GN or SIL (p < 0.001). Although the respective RPE was higher for SIL than for GN (p < 0.01) at every level of exercise, WT and EXT were no different. These data indicate that perceived effort can be significantly influenced by external factors. This in turn suggests that the use of distractive stimuli during exercise training programs with patients with COPD may significantly decrease perceived symptoms of respiratory discomfort, thus allowing the patient to exercise to a higher intensity, and potentially achieving more effective exercise reconditioning training

Two groups of 24 subjects each attempted to discriminate between large elastic and resistive loads during 50 randomized presentations of each load. Breathers inspired from the loads through a J valve, whereas pullers reciprocally stroked the plunger of a 2-liter syringe connected to the J valve. A range of load durations was obtained in each subject by prematurely unloading approximately one-half of the trials at graded times from their onset. Breathers produced random discrimination scores [50.8 +/- 2.5% (SE) correct] when loaded inspirations were shorter than unloaded inspirations [trials in which both loads induced equal airway pressure (and probably respiratory muscle tension) waveforms] and nonrandom discrimination scores (65.7 +/- 2.8% correct) when loaded inspirations were longer than unloaded inspirations (trials in which both loads induced different waveforms). In contrast, pullers produced nonrandom discrimination scores (62.2 +/- 2.9% correct) when loaded airflow durations were shorter than unloaded inspirations [trials in which both loads induced equal line pressure (and therefore limb muscle tension) waveforms]. Supplemental audio feedback related to instantaneous airflow (an expression of movement) improved load perception in breathers (to 64.2 +/- 3.0% correct; P < 0.01), indicating that airflow feedback introduced load-specific information that was lacking during breathing but redundant during pulling. In support of this hypothesis, airflow feedback by itself enabled a third group of listeners to identify load type with equal accuracy as pullers but with greater accuracy than breathers. These findings suggest that 1) uniformed subjects rely heavily on feedback from airway pressure and/or muscle tension receptors to perceive added loads to breathing and 2) limb mechanoreceptors provide a more sensitive appreciation of movement than do respiratory mechanoreceptors