Differences in pain perception in women using concentric and monopolar needles.

OBJECTIVE: To examine pain perception using concentric needle electrodes and monopolar needle electrodes in an all-female study group without underlying hand or arm pain complaints, using study subjects as their own controls. DESIGN: Prospective randomized study. Two muscles--the biceps and abductor pollicis brevis (APB)--were examined using both a concentric needle electrode and a monopolar needle electrode. SETTING: University community. PARTICIPANTS: Eighty healthy female employees at the University of Utah and Primary Children's Hospital were enrolled. All completed the study. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Pain scores. Posttest verbal analog pain scale (0-10) measures were obtained after each muscle was studied. A subset of subjects (n=51) was asked to identify needle preference after completion of the study. RESULTS: There was no significant difference in mean pain scores between the concentric needle electrode and the monopolar needle electrode (3.06 and 3.10, respectively; P=.803). The APB muscle was significantly more painful than the biceps muscle with both needle types (mean pain scores, 3.92 and 2.24, respectively; P<.001). In the subset of subjects asked to identify needle preference after completion of the study, 21 chose a concentric needle electrode and 30 a monopolar needle electrode. This difference was not statistically significant. However, verbal analog pain scores were lower with the needle preferred by each subject (P<.20). CONCLUSIONS: There is no significant difference in mean pain scores reported between a concentric needle electrode and a monopolar needle electrode. Subjects were clear on the needle they preferred, and the pain scores reported for the less painful needle were lower than those for the other needle.

Pilocarpine-induced sweat gland function in individuals with multiple sclerosis.

This investigation tested the hypothesis that cholinergic sweat function of individuals with multiple sclerosis (MS) (MS-Con; n = 10) is diminished relative to matched healthy control subjects (Con; n = 10). In addition, cholinergic sweat function was determined before and after 15 wk of aerobic training in a subgroup of individuals with MS (MS-Ex; n = 7). Cholinergic sweating responses were assessed via pilocarpine iontophoresis on ventral forearm skin. A collection disk placed over the stimulated area collected sweat for 15 min. Sweat rate (SR) was calculated by dividing sweat collector volume by collection area and time. Iodine-treated paper was applied to the stimulated area to measure number of activated sweat glands (ASG). Sweat gland output (SGO) was calculated by dividing SR by density of glands under the collector. Sweat gland function was determined in MS-Ex to test the hypothesis that exercise training would increase sweating responses. No differences in ASG were observed between MS-Con and Con. SR and SGO in MS-Con [0.18 mg.cm(-2).min(-1) (SD 0.08); 1.74 microg.gland(-1).min(-1) (SD 0.79), respectively] were significantly lower (P < or = 0.05) than in Con [0.27 mg.cm(-2).min(-1) (SD 0.10); 2.43 microg.gland(-1).min(-1) (SD 0.69)]. Aerobic exercise training significantly (P < or = 0.05) increased peak aerobic capacity in MS-Ex [1.86 (SD 0.75) vs. 2.10 (SD 0.67) l/min] with no changes in ASG, SR, and SGO. Sweat gland function in individuals with MS is impaired relative to healthy controls. Fifteen weeks of aerobic training did not increase stimulated sweating responses in individuals with MS. Diminished peripheral sweating responses may be a consequence of impairments in autonomic control of sudomotor function.

Physiological measures of therapeutic response to interferon beta-1a treatment in remitting-relapsing MS.

OBJECTIVE: This pilot study was designed to determine the effects of interferon beta-1a (IFNB) therapy (Avonex) on cortically evoked motor potentials (MEPs) during resting and fatigued states in individuals with multiple sclerosis (MS). METHODS: Eight women with relapsing-remitting MS (mean age 36) and mean Expanded Disability Status Scale (EDSS) score of 3.1 were evaluated before and after 3, 6, and 12 months of IFNB therapy. At each test period, MEPs were recorded at rest and following a fatigue paradigm (3 min maximal contraction). Effects of IFNB on neurological and functional (7.7 m walk and 10 s finger tapping) status and fatigue were also examined. RESULTS: Recovery from post-exercise depression of MEP amplitudes (PED) was 41, 43, and 43.5% faster at 3, 6, and 12 months, respectively, compared to baseline (P < 0.05). Percent reduction of MEP amplitude was significantly less at 6 months (P < 0.05) The majority of subjects (5/8 at 3 months; 6/8 at 6 and 12 months) reported decreased physical fatigue. Functional improvements were observed for walk and finger tapping scores after 3 months of IFNB treatment. MEP latencies were unchanged over the course of the intervention. CONCLUSIONS: Results indicate that IFNB therapy may improve the rate of recovery from central fatigue. SIGNIFICANCE: Transcranial magnetic stimulation (TMS) may have promise as an objective physiological tool to evaluate disease activity and treatment responses in MS.

Multiple sclerosis attacks are associated with picornavirus infections.

Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system, which often follows a relapsing-remitting (RR) course with discrete attacks. MS attacks have been associated with upper respiratory infections (URIs), but the specific viruses responsible have not been identified. We studied a cohort of 16 RRMS patients experiencing URI and followed them for clinically identifiable attacks. The viral causes of 21 separate URIs were investigated using culture and polymerase chain reaction (PCR) of nasal swab specimens, and by serology. Sibleys 'at-risk' period for MS attacks, beginning two weeks before and continuing for five weeks after a URI, was used for the analysis. Seven of the nine (78%) URIs due to picornaviruses were associated with an MS attack during the at-risk period. By contrast, only two of 12 (17%) picornavirus-negative URIs were associated with an MS attack (P = 0.01). The possible role of picornaviruses in the pathogenesis of MS deserves further study.

Thermal regulatory responses to submaximal cycling following lower-body cooling in humans.

This study compared the effects of pre-exercise cooling with control water immersions on exercise-induced thermal loads derived from steady-state submaximal exercise. Eight healthy male participants [mean (SEM) age 29 (1) years, maximal oxygen uptake 3.81 (0.74) l x min(-1), and body surface area 1.85 (0.11) m(2)] took part in experiments that included 30 min of baseline data collection [ambient temperature 21.3 (0.2 degrees C)], 30 min of immersion in water to the level of the supra-iliac crest [water temperatures of 35.1 (0.3) degrees C for thermoneutral and 17.7 (0.5) degrees C for precooled treatments], and 60 min of cycling exercise at 60% of maximal oxygen uptake. No significant differences were noted during exercise in net mechanical efficiency, metabolic rate, O(2) pulse, or ratings of perceived exertion between the two treatments. Precooling resulted in a significant negative body heat storage during immersion and allowed greater heat storage during exercise. However, net body heat storage for the entire protocol was no different between treatments. Cooling significantly lowered rectal, mean skin, and mean body temperatures as well as more than doubling the exercise time until a 0.5 degrees C rectal temperature increase was observed. The cooling trial significantly delayed onset of sweating by 19.62 min and decreased sweat rate by 255 ml x h(-1) compared to control. Thermal and sweat sensation scores were lower after the cooling treatment compared to control. These data suggest that lower-body precooling is effective at decreasing body heat storage prior to exercise and decreases reliance on heat dissipation mechanisms during exercise. Therefore, this unique, well-tolerated cooling treatment should have a broader application than other precooling treatments.

Electromyography of sternocleidomastoid muscle in ALS: a prospective study.

Needle electromyography (EMG) of the tongue is difficult to perform because of frequent uncontrollable movement. We chose the sternocleidomastoid (SCM) muscle as a possible alternative for assessing the involvement of the rostral neuraxis in amyotrophic lateral sclerosis (ALS). We prospectively studied 21 ALS patients during our initial diagnostic evaluation. EMG parameters that we recorded included the presence of abnormal spontaneous activity, pattern of motor unit potential recruitment, and configuration of motor unit action potentials. For the six patients with bulbar-onset ALS, three had abnormalities in the SCM and three had abnormalities in the tongue. In contrast, for the 15 patients with limb-onset ALS, 9 had abnormalities in the SCM, and only 3 had abnormalities in the tongue. Our results demonstrate the utility of needle EMG of the SCM in the evaluation of ALS. EMG of the SCM carries a similar sensitivity as the tongue in ALS patients with bulbar symptoms, but is more sensitive than the tongue in patients without bulbar symptoms. SCM innervation includes the rostral cervical cord and brainstem, and EMG abnormalities in this muscle support a diffuse involvement, which is unique to ALS.