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Biomedical subjects

C M Foley

Publications and source records attributed to C M Foley.

23 records · Page 2Linked to original sources

Classifying multidimensional stimuli: stimulus, task, and observer factors.

When observers decide how to classify stimuli, they often employ one of two types of information: identity along one particular dimension or overall similarity. The present studies examined interrelations among the factors which determine the use of these types of information. Participants' classifications of certain types of materials (e.g., size and brightness, length and density) revealed strong individual differences, were related to the individual's response tempo and selective processing ability, and were influenced by task demands. Classifications of other materials (e.g., saturation and brightness) did not reveal individual differences, were not affected by response tempo and selective processing ability, and were unaffected by changes in task demands. The former, but not the latter, types of materials have also been found to be influenced by developmental differences. The results are consistent with the idea that differences in response tempo and selective processing ability underlie observer differences (both individual and developmental) and that certain types of stimuli which are not susceptible to such influences set boundary conditions for observer differences. The results are discussed within an integral-to-separable model of processing.

Adult↗

Encephalopathy in infants and children with chronic renal disease.

The examination of five pediatric patients with encephalopathy secondary to chronic renal failure has indicated a stereotyped sequence of neurologic signs and symptoms including ataxia, loss of motor abilities, myoclonus, seizures, dementia, and bulbar dysfunction. Both the patients with CNS dysfunction and a control group selected for a similar degree of renal failure had increased levels of serum phosphate, alkaline phosphatase, and parathyroid hormone. Serial EEGs in the affected group revealed progressive slowing and an increase in paroxysmal features. No specific neuropathologic findings were noted in one patient.

Brain Diseases↗

Encephalopathy in children with chronic renal failure.

The progressive encephalopathy observed in 5 children with chronic renal failure was clinically similar to the so-called dialysis encephalopathy of adults, except that it was not related to dialysis therapy. Renal osteodystrophy is more prevalent in children than in adults and often more severe. The attempt to control the crippling deformities of renal osteodystrophy in growing children with renal insufficiency has led to the use of large quantities of aluminum containing antacids. The encephalopathy observed in children with chronic renal failure may be related to the oral ingestion of aluminum containing compounds in the presence of persistent secondary hyperparathyroidism. We suggest that alternative methods for the adequate control of serum phosphorus levels should be sought and indications for parathyroidectomy in children reevaluated. During the past 18 mos we have lowered the dose of aluminum containing compounds to 50 to 100 mg/Kg/day in our patients with progressive renal failure and recommend parathyroidectomy. No new cases of the encephalopathy have occurred.

Age Factors↗

Value of plasmapheresis in hepatic encephalopathy.

Plasmapheresis is used for treating the complications of liver failure. We performed plasmapheresis on 6 children with hepatic encephalopathy resulting from acute hepatic failure and prospectively assessed its effects on neurologic and electrophysiologic (electroencephalography and evoked potentials) function. Clinical improvement was observed in 3 of 6 patients; changes in the serum ammonia value or the results of initial electrophysiologic tests did not predict the patient response. Two patients underwent transplantation after neurologic improvement was produced by plasmapheresis; however, despite plasmapheresis, 4 patients progressed to brain death. Our data demonstrate that plasmapheresis may transiently improve the encephalopathy of acute hepatic failure but is not curative alone. Therefore, plasmapheresis may be a useful adjunct in the treatment of liver failure, potentially improving the pretransplantation status of the patient.

Brain Stem↗