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Biomedical subjects

R L Harmon

Publications and source records attributed to R L Harmon.

17 recordsLinked to original sources
PubMed1996

Trends in incidence of hospitalization for traumatic brain injury in Wisconsin from 1989 through 1992.

To aid in determining health care service needs, Wisconsin Department of Health and Social Services (DHSS) data on Wisconsin hospital discharges for traumatic brain injury (TBI), using ICD-9-CM codes for intracranial injury with and without skull fracture, and Wisconsin Department of Transportation data on incapacitating non-fatal head injuries (INHI) from traffic accidents from 1989 through 1992 were reviewed. Yearly TBI hospital discharges in Wisconsin declined 15.0%, and by 23.9% for Milwaukee County residents, over 1989 through 1992, correlating closely with changes in yearly INHI in Wisconsin (r = 0.999; p < 0.01) and in Milwaukee County (r = 0.989; p < 0.05). Using 1990 census data the yearly TBI risk ratio for Milwaukee County residents compared to the rest of Wisconsin increased from 1989 (1.76) to 1990 (1.92) and then decreased in 1991 (1.83) and 1992 (1.51). The results of this pilot study suggest there was a decrease in the incidence of hospitalization of patients with TBI in Wisconsin from 1989 through 1992, paralleling a decline in INHI from motor vehicle accidents. There appeared to be a relatively greater decline in these patients in Milwaukee County from 1991 to 1992 as compared to the rest of the state. The techniques employed in this study may be used to help assess rehabilitation service needs in other areas.

Brain Injuries↗
PubMed1996

Use of clonidine for treatment of spasticity arising from various forms of brain injury: a case series.

Spasticity may occurs as a result of different types of brain injury. The experience with six patients, aged 17-73 years, treated with clonidine for spasticity due to brain injuries of various causes is presented. These cases include a patient with traumatic brain injury, three patients with intracranial haemorrhage, a patient with a right basal ganglia stroke 3 years prior to a left subdural haematoma associated with a fall, and a patient with cerebral palsy. To varying degrees for each patient, clonidine was effective in reducing extremity hypertonicity. A possible mechanism of action is discussed. These case findings suggest clonidine may be useful in the management of spasticity associated with various forms of brain injury, and that formal studies of clonidine for this application appear warranted.

Adolescent↗
PubMed1995

Electromyographic and neuromuscular variables in post-polio subjects.

OBJECTIVE: Post-polio subjects experience functional deterioration many years after developing acute poliomyelitis and have been shown previously to have a deficit in strength recovery after isometric activity. This study characterized the size and stability of the motor units in a group of post-polio subjects with macro and single fiber electromyography (EMG) and correlated these variables with isometric strength, endurance, "work capacity," and strength recovery after fatiguing isometric exercise. DESIGN: A cohort of 12 post-polio subjects was tested for neuromuscular function. Electromyographic variables were determined on a separate day. SETTING: Volunteers were recruited from the community and tested in our neuromuscular research laboratory. SUBJECTS: A volunteer sample was obtained from advertisements. All subjects acknowledged post-polio syndrome symptoms. MAIN OUTCOME MEASURES: Neuromuscular variables were isometric knee extension peak torque, endurance (time to exhaustion) at 40% of maximal torque, tension time index, and recovery of torque at 10 minutes. Electromyographic variables were macro EMG and single fiber EMG (percent blocking and jitter). RESULTS: Macro EMG amplitude was ninefold the control value, and both jitter and blocking were greatly increased in comparison to control values. Isometric strength significantly (p < .05) correlated negatively with macro EMG amplitude. CONCLUSIONS: The weakest subjects had the greatest number of muscle fibers within the motor unit (as measured by macro EMG amplitude). Jitter and blocking did not correlate with neuromuscular function.

Adult↗
PubMed1994

Sparing of motor function after cortical injury. A new perspective on underlying mechanisms.

Historically, many theories have been offered to explain recovery of function following permanent brain injury. Because specific functional deficits often occur after injury to certain neuroanatomical locations, it has been tempting to suggest that within the brain, structure equals function (this interpretation, of course, has its roots in "phrenology", the 19th-century practice of detecting mental and behavioral traits by examining the skull's shape). Views that were common until recently emphasized structural and functional rigidity in the brain, which would seem to provide little opportunity for the occurrence of compensation. However, the observation that a considerable amount of spontaneous functional recovery occurs after many permanent brain lesions requires some explanation for the recovery that involves modification of intact portions of the brain. Recent research has provided data that reveal several forms of brain plasticity, including changes in neurotransmitter sensitivity, collateral sprouting, and diaschisis. Evidence supporting claims that beneficial behavioral recovery occurs through such physiological modifications in the brain are abundant in the literature, although, in general, there has not been any empirical establishment of causality.

Animals↗
PubMed1994

Comparative effects of fluoxetine, amitriptyline and serotonin on functional motor recovery after sensorimotor cortex injury.

A recent investigation of the effects of the antidepressants desipramine and trazodone on behavioral recovery in brain-injured animals suggested that antidepressants, which act to increase noradrenergic activity in the brain, may facilitate the rate of recovery, whereas those that act to increase serotonergic (5-HT) activity may hinder recovery and reinstate deficits in recovered animals. The present study was designed to evaluate these findings further by assessing the effect of a single intraperitoneal injection of fluoxetine (a relatively pure 5-HT reuptake blocker), amitriptyline (a mixed 5-HT and noradrenergic reuptake blocker with alpha 1-adrenergic receptor blocking activity) or a single intraventricular infusion of 5-HT on recovery of beam-walking ability in animals with a unilateral sensorimotor cortex injury. None of the drugs significantly affected the rate of recovery. Although fluoxetine was ineffective in reinstating the motor deficit in recovered animals, amitriptyline reinstated the deficit in a dose-dependent fashion. Infusion of 5-HT resulted in an extremely transient reinstatement of the deficit, which was largely attributable to its short-term sedative properties. These results suggest that 5-HT may be less involved in functional recovery than previously thought. They also add further support to previous findings that indicate that drugs which act to antagonize alpha 1-adrenergic activity (e.g., phenoxybenzamine) may interfere with motor recovery after sensorimotor cortex injury. An appreciation of the potential impact of certain antidepressants on functional recovery in brain-injured patients appears warranted.

Amitriptyline↗
PubMed1993

Effects of trazodone and desipramine on motor recovery in brain-injured rats.

Rats pretrained to walk a narrow balance beam received unilateral sensorimotor cortex lesions, resulting in a contralateral transient paresis that lasted 14 days. In a dose-dependent manner, a single injection of the antidepressant trazodone given 24 hours after injury transiently slowed motor recovery compared with injured controls. After final recovery level of motor function, a reinjection of trazodone reinstated the hemiparesis for up to 6 hours. In other animals, a single injection of the antidepressant desipramine significantly facilitated motor performance when compared with injured controls. Desipramine had no deleterious motor effect when administered to animals that had recovered on the beam-walking task. These findings would suggest that the predominantly noradrenergic neurotransmitter effects of desipramine may facilitate, and those of the predominantly serotonergic trazodone may hinder, the recovery of locomotor performance after cortical injury in rats. Further studies appear indicated, including applying these findings to the clinical setting.

Analysis of Variance↗
PubMed1986

Rehabilitation of patients with end-stage renal failure after lower extremity amputation.

Four patients with end-stage renal failure on maintenance hemodialysis and one patient with near end-stage renal failure received inpatient rehabilitation following lower extremity amputation. All were prosthetically restored. Three of the patients had bilateral below-knee amputations and were ambulatory at the time of discharge, including the patient with near end-stage renal failure who was on maintenance hemodialysis at follow-up. One unilateral below-knee amputee was also ambulatory at discharge. The other unilateral below-knee amputee had an ulcer on the other foot and used a pylon for transfers only. To assess the prevalence of patients on maintenance hemodialysis with lower extremity amputations, a survey of 310 patients at four dialysis units was performed. Of the 310 patients 2.9 percent had at least one amputated lower extremity and 1.0 percent had bilateral lower extremity amputations. Preliminary data and the potential for functional results following prosthetic restoration suggest the need for further research concerning prosthetic restoration in the lower extremity amputee with end-stage renal failure.

Adult↗
PubMed1984

Thyroid hormone and the TRH stimulation test in refractory depression.

Seven of 21 refractory depressed patients responded within 7 days to combined thyroid hormone-antidepressant treatment. Five of the 7 responders revealed evidence of subclinical hypothyroidism, suggesting that this subpopulation of depressed patients may benefit most from adjunctive thyroid hormone.

Adult↗
PubMed1983

Susceptibility of sows to experimentally induced Escherichia coli mastitis.

A study was conducted to compare susceptibility of sows from 2 herds to experimentally induced Escherichia coli mastitis. Four sows each from herds R and S were inoculated intramammarily at postpartum hour 8 with a strain of E coli shown previously to be capable of producing mastitis. After inoculation with E coli, sows from herd S had higher temperatures, lower WBC counts, and lower plasma protein:fibrinogen ratios than did sows from herd R. Inoculated sows from herd S lost 83% of newborn pigs due to starvation by 14 days after inoculation, whereas sows from herd R lost none. Control, noninoculated sows from both herds had normal temperatures, normal hematologic values, and minimal mortality of piglets. Levels of antibodies (complement fixing, enzyme-linked immunosorbent assay, and agglutinating) to E coli in preinoculation sera from the 2 populations of sows did not differ. Assay of lactoferrin by radial immunoassay revealed comparable concentrations in milk of sows from both herds during the first 24 hours after sows had delivered, but significantly higher values were detected in milk from sows of herd S at postpartum days 2 and 3. The basis for the marked difference in susceptibility to E coli-induced mastitis was not determined except that "susceptible" sows (herd S) were from a conventional herd and "resistant" sows (herd R) were from a specific-pathogen-free herd.

Animals↗
PubMedDate not supplied

Low-intensity, alternate-day exercise improves muscle performance without apparent adverse effect in postpolio patients.

The purpose of this study was to examine the effect of a low-intensity, alternate-day, 12 wk quadriceps muscle-strengthening exercise program on muscle strength and muscle and motor unit integrity in 12 postpolio patients. Patients performed six to ten repetitions of a 5-s duration knee extension exercise with ankle weights. After completing six repetitions, patients rated the perceived exertion (RPE) in the exercised muscle. The patient continued repetitions until RPE was >/= 17 or ten repetitions were performed. The weight was increased the next exercise day whenever the RPE was < 17 after ten repetitions. Before and after the training program, median macroamplitude as well as jitter and blocking were determined electromyographically (EMG), serum creatine kinase (CK) was measured, and quadriceps muscle strength was assessed. The ankle weight lifted after 2 wk of training and at the end of the program were also recorded. Although the ankle weight lifted at the end of the program significantly (P < 0.05) increased from a mean +/- SD of 7.1 +/- 2.7 to 11.2 +/- 4.7 kg, the dynametrically determined muscle strength measures did not significantly (P > 0.05) increase. The EMG and the serum CK variables also did not significantly (P >0.05) change as a result of the exercise program. We conclude that performance was improved, as demonstrated by an increase in the amount of weight the patients lifted in the exercise program. No evidence was found to show that this program adversely affected the motor units or the muscle as the EMG and CK did not change.

Adult↗
PubMedDate not supplied

Bilaterality of ulnar neuropathy at the elbow.

The electrodiagnostic records of 49 patients with ulnar neuropathy at the elbow (UNE) on at least one side were reviewed. Of these, 18 (36.7%) had contralateral and 1 (2.0%) had probable contralateral involvement, for a total of 19 patients (38.8%) with bilateral UNE. The upper extremity presenting symptoms were unilateral in 13 (68.4%) of the patients with bilateral UNE. Differences in associated clinical history data and concurrent electrodiagnostic findings were not clinically or statistically significant between the unilateral and bilateral UNE groups. This pilot study suggests the incidence of UNE bilaterality may be high in some populations and that, when UNE is encountered electrodiagnostically, the contralateral extremity should also be tested. Further studies to determine what factors are related to the bilaterality of UNE appear indicated.

Adult↗
PubMedDate not supplied

Electromyographic assessment of spasmodic dysphonia patients prior to botulinum toxin injection.

Electromyographic (EMG) evidence of inappropriate muscle activity (IMA) in the cricothyroid (CT) and vocalis (V) (thyroarytenoid) muscles was correlated with clinical voice measures in 32 patients with spasmodic dysphonia (SD). Subjective voice rating and quantified fluency and laryngeal diadochokinesis measures were obtained prior to botulinum toxin (Botox) injection into the V muscles. Pre-Botox EMG was performed using a monopolar needle electrode. Each muscle was sequentially examined at rest, during vocal click, scale, sustained "E" at different pitches, and repeated "E" voicings for brief periods. A three point EMG severity scale was used to grade the amount of IMA seen in each muscle. EMG evaluation showed no evidence of lower motor neuron involvement but did reveal IMA in 81.3% of the subjects. There were no significant correlations for the patients between different EMG-based IMA severity scales and the measures of voice quality and sound production. EMG did discriminate between predominantly adductor and abductor SD pattern types, but could not correctly differentiate a mixed SD group. Those patients with adductor SD displayed IMA in the V and CT muscles, while those with abductor SD displayed more IMA in the CT than the V muscles. Sequential EMG assessment of CT and V IMA in SD did not predict clinical severity or outcome following Botox injection into the V muscles.

Adult↗
PubMedDate not supplied

Close-proximity concentric and modified single fiber electromyographic recordings using revised techniques with a paired wire electrode.

Using a combined concentric (CN) and modified single fiber (MSF) electromyographic needle electrode with both recording surfaces at the tip approximately 25 microns apart, 24 motor unit potentials (MUPs) were recorded from one extensor digitorum communis muscle, triggering from either the CN or MSF channel in equal numbers and averaging both CN and MSF recordings. Filter settings were 20-10,000 Hz. Correlations of MUP amplitude, phases, turns, negative turns (NTs), and main spike duration, but not rise time or duration, between the CN and MSF recordings were statistically significant (P < 0.05). Mean +/- SD numbers of estimated single fiber potentials (ESFPs) and NTs for the MSF recordings were 1.17 +/- 0.38 and 1.54 +/- 0.72. Correlations between numbers of ESFPs and turns, NTs and phases, NTs and turns, and NT and main spike duration for the MSF and CN MUP recordings, respectively, were statistically significant (P < 0.05). The study findings using these techniques continue to support evidence that one or a few muscle fibers contribute to the main spike component of the MUP.

Action Potentials↗
PubMedDate not supplied

A comparison of close proximity concentric and modified single fiber electromyographic recordings from extensor digitorum communis.

Using a combined concentric (CN) and modified single fiber (MSF) electromyography (EMG) needle electrode with both recording surfaces at the tip approximately 25 microns apart, 30 motor unit action potentials (MUAP) were recorded from one extensor digitorum communis (EDC) muscle, triggering from the CN and averaging both the CN and MSF recordings. Correlations of MUAP amplitude (r = 0.767), number of turns (r = 0.839), and number of negative-going-positive-going turn (NT) (r = 0.737) between the CN and MSF recordings were statistically significant (p < 0.001). For NTs common to both recordings, correlations of rise time (r = 0.866), amplitude (r = 0.816), and interpeak interval (IPI) (r = 0.999) were statistically significant (p < 0.001). Mean +/- SD single fiber potentials (SFP), approximate SFP with rise times less than 500 microseconds, and NTs for the MSF recordings and NTs for the CN recordings were 0.73 +/- 0.69, 1.20 +/- 0.48, 1.83 +/- 0.87, and 1.93 +/- 0.78, respectively. This study supports evidence that one or a few SFP contribute to the spike component of the MUAP.

Action Potentials↗