"Pure word deafness": implications for assessment and management in communication disorder--a report of two cases.

In "pure word deafness" after acquired brain injury, the auditory comprehension of words is much more impaired than other aspects of communication or cognition. Two cases are presented, one early and one late presentation. The key to diagnosis of communication disorders is to remember to assess all six basic aspects of language function and to be vigilant for coexisting diagnoses that can complicate such assessment (especially psychiatric diagnoses). Rehabilitation management of impaired communication should emphasize the teaching of specific coping mechanisms to the patient and to all others who are involved.

Comparison of disability behavior after different sites and types of injury in a workers' compensation population.

In this study, an extensive data set from a regional workers' compensation system was analyzed to determine whether particular sites or types of injury were associated with prolonged disability. This data shows a similar pattern of vocational disability for almost all sites and types of injury. A workers' compensation carrier collects data for financial purposes related to insurance, and such data therefore has several serious potential deficiencies when used for clinical research. However, published data on disablement after nonoccupational trauma shows similar patterns of vocational and nonvocational disability, and also shows dependence on severity of injury. In both settings, head injury is associated with greater occupational disability. Because treatment, policy, and medicolegal decisions are based on the impression of "typical disability" for particular sites and types of injury, there is a need for better documentation of post-traumatic disablement in compensation settings and in noncompensation settings. This should include better classification of the cause, type, and severity of the injury, and of the functional outcome in terms of both the resumption of occupational and nonoccupational roles, and of persistence in these roles.

Chopart prosthesis and semirigid foot orthosis in traumatic forefoot amputation. Comparative gait analysis.

Gait was analyzed in seven otherwise healthy males at least 11 mo after they had recovered from a traumatic unilateral transmetatarsal amputation incurred during the course of their usual occupation. All seven were fitted with a semirigid foot orthosis. Four were also fitted with a Chopart prosthesis. Gait was evaluated with forceplate measurements of ground reaction force during free walking, by clinical observation of such ambulation on videotape, and by the subjective impression of the men as obtained by a questionnaire. In all men, with unmodified footwear, with the orthosis, and with the prosthesis, the forceplate data showed an abnormal pattern characterized by reduced stance duration and deficient forward propulsion on the amputated side. The abnormality and asymmetry of ground-reaction forces were less with greater preserved stump length and for a given stump length were with the above-ankle concept (Chopart) prosthesis than with the below-ankle concept. These features were recognized during the clinical analysis of all footwear, but there was an extra irregularity of weight progression noted with the fixed ankle of the Chopart prosthesis. The questionnaire reported stump problems to be the principal difficulty, and the follow-up revealed persistent attempts at surgical management including consideration of amputation at a higher level. It was concluded that the patient and the surgeons are likely to choose preservation of limb length over considerations of function during acute care and that the prosthetic concept best suited to deal with the resulting stump should emphasize unloading the distal part of the stump and smoothing out the impulsive force peak on the stump in late stance to minimize pain and to enhance ambulation capacity.

Relationship of performance on the ERGOS work simulator to illness behavior in a workers' compensation population with low back versus limb injury.

A prospective blinded cohort study was performed to test for a difference in the pattern of physical activity factors measured with the ERGOS work simulator in subjects with low back injuries versus those with limb injuries. Also tested was the relationship between physical activity factors measured with the ERGOS and several psychological tests and measures of nonorganic pain behavior in subjects with low back pain. Subjects were 70 men, 22 to 64 years old, who attended a 2-week physical capacity assessment after undergoing rehabilitation for a work-related injury. In subjects with a complaint of low back pain, nonorganic pain behavior was measured with the Waddell score. In addition, two brief psychological tests, the Coopersmith Self-Esteem Inventory and analog self-rating of wellness, were administered. It was found that subjects with low back complaints underperformed globally in comparison with subjects with limb complaints. This underperformance was statistically significant (P < .05) for 7 of 13 strength variables and 2 of 7 dexterity variables. In the subjects with low back complaints, those who exhibited excessive illness behavior (Waddell score, 3 to 5) performed significantly worse on all 13 strength variables and on 3 of 7 dexterity variables. In the subjects with low back complaints, those with low self-assessment ratings were found to have a high Waddell score (P < .01) and to perform significantly worse (P < .05) on 12 of 13 strength variables and 6 of 7 dexterity variables. There were no significant relationships (P > .05) between Coopersmith Self-Esteem score and Waddell score or performance on ERGOS testing.(ABSTRACT TRUNCATED AT 250 WORDS)

Pattern of performance in workers with low back pain during a comprehensive motor performance evaluation.

STUDY DESIGN: Tests of limb and back motor performance were administered to males with low back pain at the completion of a back-school program. OBJECTIVES: The objective of the study was to determine the relationship between such motor performance and the propensity for abnormal illness behavior as indicated by the Waddell score. SUMMARY OF BACKGROUND DATA: Previous studies in similar subjects had revealed a nonbiologic pattern of lumbar strength and movement in back-school patients, and correlations between lumbar variables, Waddell score, and 'global' psychologic measures. This suggested that psychologic factors might affect motor performance in body segments unrelated to the low back in such patients. RESULTS: Mean performance of the group with a high Waddell score (indicating a propensity for abnormal illness behavior) was lower on all tests, including those that did not involve the low back, in comparison to the group with a low Waddell score (P < .01, sign test). CONCLUSION: For all members of this population of patients, motor performance on dynamometry of any body segment does not necessarily reflect the maximum physical capacity.

Objective evaluation of functional capacity: medical, occupational, and legal settings.

Clinicians are called upon to perform objective evaluation of functional capacity in a variety of treatment and evaluation settings. To assist the clinician in selecting the appropriate testing methods for assessment of functional capacity in different settings, a survey of available techniques is presented. It is structured around the goals of treatment as the patient progresses from the stage of acute injury or disease through early postacute care to long-term rehabilitation. The role of the clinician in treatment of the patient is contrasted to the role of the clinician in evaluation of the patient for reasons other than making clinical decisions. In particular, the specific demands of workers fitness and risk evaluation are described. The goal-related differences in the design and the correct use of clinical dynamometers vs. work simulators are presented. The key concepts are the professional role of the clinician, reliability of measurements, and validity in the sense of the decisions one is justified in making based on the results of these measurements in a particular context.

Concurrent validity of the ERGOS work simulator versus conventional functional capacity evaluation techniques in a workers' compensation population.

A prospective blinded cohort study was performed in an interdisciplinary vocational evaluation program to investigate the concurrent validity of the ERGOS work simulator in comparison to current methods of evaluation. Seventy men and eight women, aged 22 to 64 years, who attended for a 2-week physical capacity assessment participated in the study. Physical activity factors as defined by the Canadian Classification and Dictionary of Occupations and the American Dictionary of Occupational Titles were assessed for all subjects under three evaluation conditions: the ERGOS work simulator, an exercise-oriented physical evaluation by a rehabilitation therapist, and performance of project-format industrial tasks. In addition, 17 men and 7 women were assessed with VALPAR standardized work sample tests. The statistical significance of the relationships between results obtained by the various evaluation methods was examined. There was a strong correlation between the ERGOS dynamometry and the clinical assessment of strength for all standard movements tested (P < .001). The Methods Time Measurement rating by the ERGOS for dexterity variables, according to industrial engineering standards, tended to rate subjects as more restricted than did the clinical evaluators. There was a significant relationship (P < .001) between the "overall physical activity rating" from ERGOS dynamometry, clinical evaluation, and performance in an industrial workshop setting. There was also a significant relationship (P < .001) between the "overall physical activity rating" for endurance of a full workday produced by the 4-hour ERGOS evaluation and by the 2-week functional capacity evaluation.(ABSTRACT TRUNCATED AT 250 WORDS)

MELAS syndrome with mitochondrial tRNA(Leu)(UUR) mutation: correlation of clinical state, nerve conduction, and muscle 31P magnetic resonance spectroscopy during treatment with nicotinamide and riboflavin.

We report a patient with mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes treated with riboflavin and nicotinamide for 18 months, during which time previously frequent encephalopathic spells ceased. To confirm clinical benefit, we withdrew treatment and monitored response with muscle 31P magnetic resonance spectroscopy (MRS) and sural nerve conduction studies. Of three prospectively chosen MRS variables, two changed coincidentally with clinical end points; phosphocreatine (PCr)/adenosine triphosphate recovery rates fell in parallel with sural nerve sensory amplitudes, and a drop in muscle bioenergetic efficiency (relationship of inorganic phosphate/PCr to the accelerating force of contracting muscle) coincided with development of encephalopathy. Investigations revealed a deficiency of respiratory complex I and mutation of the mitochondrial tRNA(Leu)(UUR). We suggest that a defective cellular energy state in mitochondrial disease may be partially treatable and that changes seen in appropriate muscle spectroscopy studies may parallel improvement in brain and peripheral nerve function.

Serial lumbar dynamometry in low back pain.

To determine the significance of changes in motor performance as measured by lumbar dynamometry, serial lumbar dynamometry was performed on a group of 45 male Workers' Compensation patients with chronic "mechanical" low back pain and in a group of 20 healthy male volunteers. The patients were men aged 20-60 years, whose current episode of low back pain had lasted for at least 3 months (mean 19.5 weeks, range 12-47 weeks). Testing was performed at entry into a "back school" program of therapy and again 2 weeks and 4 weeks later. The control group showed a slight improvement in almost all variables of strength and range of motion between the first and second tests but no significant change between the second and third tests. This was consistent with a learning effect. The patient group was analyzed as a whole and also in two groups based on their response to the Waddell maneuvers at entry: Waddell score 0-2 (no excessive illness behavior) and 3-5 (excessive illness behavior). As a whole, the patients showed significant progressive improvement in most variables on successive tests. The group with the low Waddell score had significantly greater strength and range of motion than the group with the high Waddell score but the trend of improvement with time was similar in the two groups. The authors conclude that in this sample of patients with low back pain, serial lumbar dynamometry reveals a progressive improvement in performance, which is greater than the improvement expected from the natural history of physical recovery and greater than the improvement expected from an increase in strength and range of motion attributable to the therapeutic exercises performed and is much larger than any learning effect related to the test procedure.

Comparative biomechanical analysis of energy-storing prosthetic feet.

Gait analysis was performed on eight men who had unilateral traumatic below-knee amputation and on nine control subjects. Each subject was given two prostheses--the Seattle Foot and the Flex Foot--which differed only in the energy-storing foot component. Analysis of subjects consisted of clinical gait observation, forceplate analysis of the ground reaction force (GRF) while using each prosthesis during level walking at the natural cadence, and evaluation of subject preference between the two prosthetic feet. In the control subjects, there was no significant asymmetry in any averaged GRF patterns or parameters. In the subjects with amputations, the amputated limb had a weaker propulsion and the nonamputated limb had a stronger propulsion than controls. This was true for both prostheses. During ambulation with the Flex Foot, there was a pattern of larger late vertical forces but smaller late anteroposterior and mediolateral forces. This is consistent with a medial heel whip, and it was observed when the Flex Foot was used. Three months after the biomechanical studies, four subjects used the Flex Foot exclusively, two used the Seattle Foot exclusively, and two used both, ie, the Flex Foot for sports and the Seattle Foot for work. Application of these results to the choice of prosthetic components is discussed.

Relative metabolic efficiency of concentric and eccentric exercise determined by 31P magnetic resonance spectroscopy.

To determine the relative metabolic efficiency (metabolic energy used per unit of mechanical energy output) of negative to positive muscular power, we used 31P magnetic resonance spectroscopy to monitor the cellular energy metabolism of limb muscles in eight healthy subjects during a nonfatiguing, mixed concentric-eccentric activity and during its concentric and eccentric components. We also studied isometric contractions. We found that in terms of the flow of metabolic energy through the muscle cells, the cost of concentric exercise at this intensity was proportional to the mechanical power generated, but the cost of eccentric and isometric exercise did not increase significantly as the apparent intensity of the exercise increased over the range studied. Although the pattern was similar in all subjects, the quantitative relationship between metabolic cost and mechanical output was different in subjects with different muscular strength. The qualitative results can be explained in the context of the known biochemistry and biophysics of the cellular contractile apparatus (sliding filament theory, with independent force generators).

Acute and chronic hypothermia in a man with spinal cord injury: environmental and pharmacologic causes.

It is well known that people with spinal cord injuries can develop hypothermia when exposed to an unusually cold environment. Hypothermia can also develop during inpatient rehabilitation, particularly as a side effect of certain medications. We present a patient with C4 incomplete spinal cord injury whose core body temperature was chronically subnormal, and who developed acute hypothermia on several occasions during inpatient rehabilitation. The results of tests of his autonomic function were abnormal. Acute hypothermia (core temperature approximately 34C) was induced when he was challenged with nifedipine. The serum level of phenytoin became elevated to toxic levels during two episodes of acute hypothermia, but the serum level of carbamazepine did not change appreciably. This case demonstrates that people with spinal cord injuries are at risk for hypothermia, that hypothermia can be induced by nifedipine, and that significant thermal challenges can occur during routine inpatient rehabilitation. In addition, hypothermia appears to affect the metabolism of phenytoin.

Anemia after traumatic spinal cord injury.

The incidence and natural history of anemia in patients with spinal cord injuries (SCI) were investigated in a prospective study of 68 patients consecutively admitted to a regional acute SCI unit. Fifty had SCI and 18 had spine injuries (SI) without neurologic deficit. Thirty-six of 41 males (88%) and six of nine females (67%) with SCI were anemic on at least one occasion. In the first two weeks after injury, in females and in males, there was no significant difference in mean hemoglobin level between SI and SCI patients. At six weeks, no male with SI was anemic, and males with SCI had significantly lower mean hemoglobin levels than those with SI (121.6 g/L vs 145.4 g/L, p less than .001). Identified early causes of anemia were blood loss due to bony soft tissue or visceral injury, gastrointestinal bleeding, and surgery. In the postacute phase (more than six weeks after injury), anemia occurred in 25 of 41 male and three of nine female SCI patients, and its occurrence was associated with the presence of an identified chronic disease, especially urinary tract infection.

Tension responses of frog skeletal muscle fibres to rapid shortening and lengthening steps.

1. A study has been carried out of the tension responses of single fibres from frog semitendinosus muscle at 4 degrees C which occur in response to rapid lengthening and shortening steps throughout the isometric tetanus. 2. Instantaneous stiffness values were calculated as the ratio of the tension change to the length change. 3. Stiffness was seen to increase more rapidly than the tension during the initial development of force and was constant during the tetanus plateau. During the relaxation phase of tension, stiffness declined more slowly than the force up to the shoulder; thereafter both declined rapidly and with a nearly similar time course. 4. Throughout the initial rise of force, the period of maximum force development and the early phase of relaxation, a rapid stretch produced a significantly greater tension change than a rapid release. The fibres appeared 'stiffer' during a stretch. 5. The experimental results are shown to be consistent with the suggestion that cross-bridges may detach during a small rapid shortening step but remain attached during a similar lengthening step.

Direct measurement of the influx of sodium in frog skeletal muscle.

When a frog's sartorius is immersed in sodium-free lithium-substituted solution at 0 degree C, the tissue sodium content declines in two distinct phases. The rate of the slow phase has a temperature dependence expected for a process dependent on metabolism (Q10, ca. 3), and sodium content (51.5 mmol/kg dry weight) equal to that measured by others using electron microprobe microanalysis. The rate of the rapid phase has a temperature dependence (Q10, 0.3-1) expected for a passive process, and a sodium content equal to that in the sorbitol space. It was concluded that incubation of a muscle at 0 degree C for 45 min in sodium-free solution will wash out almost all of the sodium in the extracellular space but will leave almost all the sodium in the intracellular space. The unidirectional sodium influx was measured by incubating a muscle in 22Na-containing Ringer's solution for a timed interval at 23 degrees C, then in sodium-free lithium-substituted solution at 0 degree C for 45 min, before analysis for ion content and radioactivity. The ratio of the specific activity of sodium in the muscle to that in the radioactive bathing solution was calculated, and the time course of its rise was used to calculate an influx rate coefficient. The use of the specific activity minimizes the error due to the loss of intracellular sodium and radiosodium which occurs during the wash in cold solution. It was found that the rate of the radiosodium uptake varied as the uptake proceeded, in a manner similar to that previously shown for the rate of the radiosodium efflux and attributed to the existence of a diversity of cell size in this muscle.

Direct measurement of sodium influx in vascular smooth muscle. Stimulation by aldosterone.

The influx of 22Na into the smooth muscle cells of incubated rat tail arteries was measured directly, in the presence and absence of 2.8 X 10(-7) M D-aldosterone. During the analysis, extracellular 22Na and 23Na were removed by incubation of the tissue in sodium-free lithium-substituted physiological salt solution at less than 3 degrees C. Aldosterone increased the influx rate coefficient by 10% (0.104 +/- 0.004 [SE] min-1, n = 13, vs 0.095 +/- 0.003 [SE] min-1, n = 13 without aldosterone; p less than 0.01) but did not significantly reduce the sodium content. We conclude from direct measurements that aldosterone acts to increase the influx of sodium in incubated tail arteries from normal rats; we conclude from measurements of the sodium influx and sodium content that aldosterone also acts to increase the efflux of sodium in this preparation.

Phenoxybenzamine-sensitive mechanically induced alterations of sodium fluxes in smooth muscle cells of the rat tail artery.

The intracellular sodium content, unidirectional radiosodium efflux, and unidirectional radiosodium influx were studied in whole rat tail arteries and in rat tail artery strips. The tissues were allowed to come to a steady condition while immersed in physiological salt solution at 37 degrees C, then were subjected to a small transient mechanical disturbance or to a larger disturbance of 5-20 min duration. The small transient disturbance caused a large transient increase in the sodium content of the cells, in the radiosodium influx, and in the radiosodium efflux. The sustained disturbance caused a sustained increase in sodium content. All effects of a mechanical disturbance were prevented by blockade of alpha-adrenoreceptors with 1 microM phenoxybenzamine. Pre-treatment of the rat with reserpine was as effective as acute treatment of the artery with phenoxybenzamine in preventing the transient increase in the radiosodium efflux. It is hypothesized that mechanical disturbances cause norepinephrine release from terminal adrenergic plexuses in the artery wall, and that the binding of norepinephrine to alpha-adrenoreceptors in the smooth muscle cells causes an increase in the sodium permeability of the cell membrane.

The "intermediate component" of the radiosodium efflux from frog skeletal muscle.

The influence of diversity in the size of the cells of the frog's sartorius on the radiosodium efflux from the muscle was investigated. Morphometric analyses of light micrographs of complete cross sections of the muscle were done in the proximal and distal regions. The results were used to predict the shape of the radiosodium washout curve under the following assumptions: the cells differ in size and shape, but each has a single internal pool of exchangeable sodium; the sodium exchange properties of the limiting membranes are the same for all cells; and the diversity of the true areas of the limiting membranes is reflected by the diversity of the apparent areas measured at the light microscopic level. Radiosodium efflux measurements were performed on similar muscles. The model correctly predicted the occurrence of a continuous decline of the fractional loss of radiosodium, which was not due to diffusional delay and which would be interpreted as a second internal compartment in a compartmental analysis, and an effect of short versus long isotope loading intervals on the efflux. It was concluded that the existence of cell size diversity satisfactorily explains the flux data. No "special region" must be postulated.

External application of antibiotic to improve survival of adult laboratory frogs (Rana pipiens).

Survival data for over 500 adult frogs (393 Rana pipiens, 35 Rana clamitans , and 97 Rana temporaria) obtained from commercial suppliers were accumulated. Frogs which developed signs of red-leg disease while being kept in 0.15% saline were cured by addition of appropriate antibiotics to the saline. The appropriate antibiotic was determined by sensitivity testing of bacteria isolated from the sick frogs. When many frogs in a shipment were sick, prophylactic treatment of the entire shipment improved the overall survival in the shipment.