Validation of the ACAS TIA/stroke algorithm.

BACKGROUND AND PURPOSE: An easily administered questionnaire and algorithm classifying transient ischemic attacks (TIAs) or strokes, and also their distribution, could be invaluable for identifying endpoints in epidemiologic studies or clinical trials of prevention and therapy of cerebral ischemia. The Asymptomatic Carotid Atherosclerosis Study (ACAS) devised a symptom-based questionnaire and algorithm for detecting events in the trial. The purpose of this study was to determine sensitivity, specificity, and agreement rates of the questionnaire and algorithm against diagnoses of a panel of cerebrovascular disease authorities. METHODS: Three hundred eighty-one men and women at eight medical centers reported symptoms of stroke, TIA, or other neurologic illness. The questionnaire was administered by trained interviewers and the responses were analyzed using the algorithm. A standardized neurologic examination was performed by a neurologist. Data were submitted to two or more external reviewers. Sensitivity, specificity, and the kappa statistic (kappa) were used to evaluate the relationship between the algorithm and the external reviewers' diagnosis. RESULTS: Of the 381 reviews, 196 were diagnosed as TIA or stroke by the external panel. The algorithm's agreement with the diagnosis of TIA or stroke was 80.1%, and kappa was 0.60. Sensitivity was 87.8%, and specificity was 71.9%. CONCLUSION: While statistical agreement rates depend on the method of sample selection, the algorithm has a high agreement with an external panel of experts and is a sensitive tool for event detection. The lower specificity indicates that careful neurologic evaluation may be required to confirm or refute events identified by the screening algorithm.

Relative validity of clinical techniques for measuring the body composition of persons with amyotrophic lateral sclerosis.

Tracking body composition is necessary to understand how amyotrophic lateral sclerosis (ALS) is affecting a patient's morphology and to provide a basis for appropriate nutritional advice throughout disease progression. Dual X-ray absorptiometry (DEXA) has been shown to reliably detect body composition changes in persons with ALS. However, this procedure is expensive and available primarily for research. The purpose of this study was to determine the relative validity of two common clinical techniques, anthropometry and bioelectrical impedance analysis (BIA), for measuring the body composition of persons with ALS. Twenty-three persons with ALS volunteered for the study; seven with primarily bulbar symptoms, five with primarily arm weakness, five with primarily leg weakness, and six with significant weakness in all extremities. On a single day subjects underwent body composition analysis by the three techniques, with DEXA serving as the criterion method. Anthropometry and BIA results were converted to lean and fat mass using eight prediction equations commonly cited in the literature. Anthropometry measures were also converted to estimates of muscle mass using two additional equations. Both BIA and anthropometry tended to overestimate lean mass and underestimate fat mass compared to DEXA. However, the BIA prediction equations had smaller mean differences, larger correlations, and smaller standard errors of estimate than the anthropometry equations. The Lukaski et al. BIA equation (Lukaski, H.C., Bolonchuk, W.W., Hall, C.B., Siders, W.A., 1986. Validation of tetrapolar bioelectrical impedance method to assess human body composition. J. Appl. Physiol. 60, 1327-1332) most closely matched the values derived by DEXA and is probably the best method for measuring the lean and fat mass of persons with ALS, as long as they maintain adequate hydration levels. The Heymsfield et al. equation (Heymsfield, S.B., McManus, C., Smith, J., Stevens, V., Nixon, D.W., 1982. Anthropometric measurement of muscle mass: revised equations for calculating bone-free arm muscle area. Am. J. Clin. Nutr. 36, 680-690) for estimating muscle mass may also be a useful clinical tool for this population. Further longitudinal studies are needed to determine whether the equations that correlated best with DEXA at a single point in time are also sensitive enough to detect changes in body composition over a period of time.

Neurosarcoidosis with unusual MRI findings.

This 53-year-old white male presented with a 4-month-history of weakness and pain. Despite an initial partial response to steroid therapy, his neurologic deterioration progressed culminating in paraparesis, paresthesias, urinary incontinence, altered mentation and a 20 lb weight loss. A gadolinium-enhanced MRI study showed a pattern suggestive of perivascular involvement. A subsequent cerebral biopsy was diagnostic for neurosarcoidosis.

Spontaneous disappearance of carotid stenosis.

Angiographic diagnosis of atheromatous plaques is usually well correlated with surgical and pathologic findings. Hemorrhage into such plaques is believed to be frequent, but is seldom diagnosed angiographically. The authors report a case of intramural hemorrhage into an atheromatous plaque with subsequent resolution. A brain scan of a woman, age 52, with right hemiparesis and dysphasia showed increased isotope uptake in the left frontotemporal region. Arteriography 10 days after onset of symptoms showed a plaque in the left carotid bifurcation. Clinical improvement followed. Repeat arteriography 12 weeks later revealed almost normal left carotid bifurcation.

Effect of dexamethasone on experimental brain edema in cats.

The authors studied the effects of dexamethasone, 0.3 mg/kg/hr administered intravenously beginning 1 hour before injury, in adult cats with brain edema secondary to cold-induced cortical lesions. Edema was quantitatively measured in cortex, gyral white matter, and central (deep) white matter at 3, 24, 48, and 72 hours, with and without dexamethasone, by determining specific gravity (density) of samples in a continuous gradient column. Cold-induced lesions resulted in edema, which was greatest in the white matter of the injured hemisphere but also present in the contralateral hemisphere. Except for a slight but significant increase in density (decreased edema) of cortex at 24 hours, dexamethasone therapy resulted in no reduction of cold-induced edema, and in some cases increased the edema.