Arthur C. Klassen

Community Education for Stroke Awareness An Efficacy Study

BACKGROUND AND PURPOSE This study examined the effectiveness of a slide/audio community education program aimed at increasing knowledge of stroke risk factors, stroke warning signs, and action needed when stroke warning signs occur. The program targets audiences at higher risk for stroke, especially individuals who are black or >50 years of age. METHODS Subjects were 657 adults living in the community or in senior independent-living settings. The study examined the effectiveness of the program when presented alone and when accompanied by discussion (facilitation) led by a trained individual. Knowledge of stroke risk factors and warning signs was assessed using parallel pretests and posttests developed and validated specifically for the study. RESULTS ANCOVA indicated that neither pretesting nor facilitation had a significant effect on posttest measures of knowledge. Paired t tests of groups receiving both the pretest and posttest demonstrated significant increase in knowledge (mean increase, 10.87%; P<0.001). ANCOVA indicated that these gains in knowledge were similar across subjects of different sex, race, age, and educational level. No significant differences could be ascribed to facilitation. CONCLUSIONS The data indicate that the slide/audio program is effective in increasing knowledge of stroke risk factors, warning signs, and necessary action in subjects of varying ages, races, and education. Pretesting and facilitation did not significantly affect the short-term acquisition of information. The slide/audio program appears to offer a short, easily used educational experience for diverse communities, whether as a stand-alone program or with facilitated discussion.

A Comparative Study of Cerebral Atherosclerosis in Males and Females

An evaluation of the influence of sex upon cerebral atherosclerosis was carried out in 5,033 consecutive autopsies studied by a special well-standardized coding technique. A sex difference in frequency of cerebral atherosclerosis appears from the fourth to the sixth decade. During this period the percentage of female cases with no atherosclerosis lags behind the percentage of male cases by a 15-year period. After the sixth decade, the frequency of cerebral atherosclerosis increases more rapidly in females, so that beyond the age of 65 years the frequency of cerebral atherosclerosis is equal in the two sexes. Furthermore, younger males show a higher degree of cerebral atherosclerosis than females of the same age and a reverse trend appears in the oldest age groups. Diabetic females have more cerebral atherosclerosis than nondiabetic males, and beyond the fourth decade they have at least as much involvement as the diabetic males.

Respiratory rate and pattern disturbances in acute brain stem infarction.

Respiratory rates and patterns were studied in 23 patients with acute brain stem infarction using impedance pneumography. Autopsy was obtained in six of eight fatal cases. Pontine lesions were present in all patients, with coexistent infarction of midbrain in four and of medulla in nine. Respiratory rate and pattern abnormalities observed included Cheyne-Stokes respiration, Cheyne- Stokes variant pattern and tachypnea. Abnormalities of respiratory rate and pattern of varying duration were observed at some time in all patients. All patients in whom prominent Cheyne-Stokes respiration or tachypnea were observed had extensive bilateral pontine lesions involving both basal and tegmental portions. However, not all patients with large pontine infarcts had Cheyne-Stokes respiration or tachypnea. Cheyne-Stokes respiration was prominent in four patients (two fatal, two nonfatal). Cheyne-Stokes variant pattern was present frequently in four patients (one fatal, three nonfatal). Sustained tachypnea developed in five patients, four of whom died. In ten patients (one fatal, nine nonfatal), normal respiratory rate and pattern predominated with only rare or occasional appearance of Cheyne-Stokes respiration or Cheyne-Stokes variant pattern, especially during sleep. The types of respiratory rate and pattern abnormalities in acute brain stem infarction were not specifically related to the level of lesions, but rather to the size and bilaterality of the lesions. Respiratory alkalosis was present in varying degrees in most patients with either tachypnea or prominent CSR.

Respiratory Pattern Disturbances in Ischemic Cerebral Vascular Disease

Impedance pneumography was used to monitor respiratory rates and patterns in 49 patients with acute ischemic cerebral vascular disease. Nine patients had clinical evidence of bilateral ischemic cerebral disease. In one of these, normal respiratory pattern was present at all times; in five, there was intermittent Cheyne-Stokes respiration; in two, there were variants of Cheyne-Stokes pattern, and one patient eventually developed sustained tachypnea with probable hyperpnea. Twenty-eight patients had unilateral cerebral infarct. In five of these, normal respiratory pattern was present at all times; in 15, there was intermittent Cheyne-Stokes respiration; six had a variant of Cheyne-Stokes respiration; two had sustained tachypnea with probable hyperpnea. In 12 patients with brainstem infarcts, Cheyne-Stokes respiration was intermittently present in four, Cheyne-Stokes variant patterns were observed in two, and sustained tachypnea with probable hyperpnea developed in six. Abnormalities of respiratory patterns occurred more frequently during sleep, in the presence of a depressed sensorium, and in patients with severe neurological deficits. Respiratory alkalosis of variable degree was present in all patients with Cheyne-Stokes respiration or sustained tachypnea with probable hyperpnea. Cheyne-Stokes respiration was not always related to bilateral cerebral lesions. Intermittent Cheyne-Stokes respiration was not closely related to immediate prognosis. Sustained tachypnea with respiratory alkalosis was associated with the highest mortality rate among patients with respiratory pattern abnormalities.

Blood Flow in the Central and Peripheral Nervous System of Dogs Using a Particle Distribution Method

In this study known activities of 85Sr and 169Yb-labeled microspheres were injected sequentially into the left ventricle of anesthetized dogs. Cardiac output was determined before and after each microsphere injection. Blood flow to brain, brain stem, spinal cord, and sciatic nerve was measured from fractional distribution of the microspheres in the tissue samples. Both blood flow and fractional uptake value tended to be higher for brain and brain stem than for spinal cord or sciatic nerve. Increases in arterial PCO2 were positively correlated with increases in blood flow to both central and peripheral nervous tissue. Initial trapping of the labeled microspheres seems to have little effect on subsequent flow to the tissue capillary bed. It appears that the particle distribution technique may provide a reasonable estimate of blood flow in central and peripheral nervous tissue of dogs.

Cerebrospinal Fluid in Cerebral Hemorrhage and Infarction

Cerebrospinal fluid (CSF) abnormalities were correlated with pathological diagnoses in 61 patients with autopsy-verified intracerebral hemorrhage or cerebral infarction. Lumbar punctures were performed within one week of onset of symptoms. The CSF color and red blood cell counts were the most useful CSF parameters in differentiating between intracerebral hemorrhage and cerebral infarction. In 75% of the patients with intracerebral hemorrhage, the CSF was either grossly bloody or xanthochromic; in 25%, the CSF was clear. In patients with cerebral infarction, the CSF was never grossly bloody; in two patients with hemorrhagic infarction, the CSF was xanthochromic. The CSF pressure, protein values and leukocyte counts were less useful in differentiating intracerebral hemorrhage from cerebral infarction. Cases with hemorrhagic infarction could not be separated from those with ischemic infarction on the basis of CSF analysis. In clear CSF, the polymorphonuclear neutrophilic leukocyte (PNL) counts were never greater than 20 per cubic millimeter. In xanthochromic or cloudy CSF, leukocyte counts, especially PNLs, were frequently elevated, occasionally to high levels.

Cerebral atherosclerosis in selected chronic disease states

Abstract The severity of atherosclerotic involvement of the intracranial cerebral arteries was assessed at autopsy in 3942 adult subjects. The values obtained in groups of subjects at various ages were correlated with the presence or absence of selected chronic disease states. The presence of clinical or pathological evidence of cerebral vascular disease, atherosclerotic heart disease, diabetes mellitus, and, to a lesser degree, chronic renal disease was associated with a relative increase in the severity of cerebral atherosclerosis. In contrast, cerebral atherosclerosis was apparently less severe in groups of subjects with malignant neoplastic disease and peptic ulcer disease. In males with cirrhosis or alcoholism, there was a possible tendency toward less severe cerebral atherosclerosis.

Sympathetic regulation of cephalic blood flow.

Blood flow to bilateral tissues (cranial and extracranial) was studied by means of the particle distribution method in two groups of anesthetized dogs (five using 25-/* radioactive microspheres, six using 15-M microspheres) and five anesthetized stumptail Macaques monkeys (8-/4 spheres) during unilateral sympathetic stimulation. The stimulatory parameters were adjusted to produce maximum pupillary dilatation. In the five dogs hemispheric and regional cerebral blood flow decreased but not significantly. Flow to the extracranial tissues decreased 82%. Hemispheric brain blood flow averaged 0.70 ml/min/gm for Paco, of 40 mm Hg. In the six dogs sympathetic stimulation did not significantly decrease cerebral blood flow but decreased flow to extracranial tissues (72.3%). At an average Paco, of 33.5 mm Hg, hemispheric blood flow to the unstimulated side averaged 0.51 ml/min/gm. In the five monkeys findings were essentially the same as those observed in the dogs. The hemispheric blood flow averaged 0.36 ml/min/gm on the nonstimulated side for an average Paco, of 36.6 mm Hg. Under the conditions studied, electrical stimulation of the cervical sympathetic nerves does not appear to modify regional or total brain blood flow in dogs and Macaques monkeys. The vascular response in oral and other extracranial tissues is very dramatic, however.

Age and cerebral atherosclerosis

Abstract The importance of age as an etiological factor in cerebral atherosclerosis was investigated by analyzing changes observed in the circle of Willis in a consecutive series of 5035 autopsies. In each of these cases, the frequency and severity of the atherosclerosis was coded by a special coding technique. Although atherosclerotic lesions have been described in infancy, particularly in the coronary arteries and the aorta, such lesions have not been recorded in the cerebral arteries within the first 2 decades of life. In this series of cases, gross atherosclerotic lesions were first found in the arteries of the circle of Willis within the 1st decade of life. The frequency of such atherosclerotic lesions remained fairly steady between 0.3 and 0.5% during the first 3 decades of life and then increased in almost linear fashion with age until the 9th decade when 98% of the patients showed some involvement. Eleven cases within the 1st decade of life showed gross atherosclerotic lesions, the youngest patient being a premature infant aged 2 days. In this case there were 13 separate plaques in the circle of Willis. Moreover, in our series of cases there were 4 out of 312 within the 9th decade (1.3%) with no gross atherosclerotic lesions visible. The presence of cerebral atherosclerosis in infants and children and its absence in a number of individuals in the 9th decade of life suggest that age is not the sole determining factor in the development of cerebral atherosclerosis.

Regional Cerebral Blood Flow in Dogs Using a Particle-Distribution Method

Summary In this study a known activity of microspheres labeled with 169Yb was injected into the left heart of lightly anesthetized dogs. Prior to injection of microspheres, cardiac output was determined by the isotope dilution technique using 42K or 86Rb. Blood flow to the cerebral cortex, white matter, thalamus, cerebellum, and caudate nucleus was determined in ml/min·g from fractional distribution of particles in tissue samples. Total brain blood flow in ml/min·g was estimated from the radioactivity observed in the remaining brain tissue. Comparison of dogs breathing air with dogs breathing 5% CO2 showed that flow values were significantly increased (p<.05) with 5% CO2 for all areas except white matter. Old dogs tended to show higher flow values than young dogs. Flow values obtained in this study were compared with values reported by others using different methods. The distribution of the particles in the brain was checked by autoradiography.