PubMed Health⌕ Search

Biomedical subjects

G Waters

Publications and source records attributed to G Waters.

4 recordsLinked to original sources
PubMed1990

Cochlear microcirculation in young and old gerbils.

Human postmortem studies as well as epidemiologic investigations have implicated the peripheral vascular system as one of the etiologic factors of presbycusis. This study uses the surface dissection microsphere method for regional cochlear blood flow analysis and morphometric techniques for quantifying capillary density in the stria vascularis. In this study 11 old and 10 young gerbils were used. Our results indicate that blood flow in the cochlea was decreased in the old gerbils. This decrease was most obvious in the lateral portion (stria vascularis). The decrease of blood flow in older animals was clearly not related to loss of strial capillaries with aging. The decreased flow to the lateral portion must arise from either decreased perfusion pressure or from increased vascular resistance. This decreased blood flow in the aged animals supports a vascular theory of presbycusis.

Aging↗
PubMed1990

Characteristics of syntactic comprehension deficits following closed head injury versus left cerebrovascular accident.

Two studies examined the ability to assign thematic roles and to coindex referentially dependent noun phrases in closed head injured adults, adult stroke patients, and normal adults. The subjects' task was to enact target sentences by manipulating toy animals. Closed head injured and stroke patients demonstrated a significant effect of syntactic structure on sentence comprehension, and the patterns of breakdown in the ability to assign thematic roles and coindex referentially dependent noun phrases were strikingly similar in the two groups. These findings suggest that syntactic comprehension disturbances are similar following left cerebral hemisphere infarction and closed head injury.

Adolescent↗
PubMed1989

Perception of unilateral lower extremity weightbearing during bilateral upright stance.

The primary purpose of this study was to describe the error in 61 healthy subjects' perceptions of weight-bearing at three target levels during bilateral upright stance. The secondary purpose was to describe the effects of age, sex, lower extremity dominance and target weightbearing level on the error in perceptions of weightbearing. Weightbearing was determined while subjects stood on digital scales. They adjusted their weight in an attempt to bear 25, 50, and 75% of their weight through a designated lower extremity. Three trials were allowed at each weightbearing target, and the results were averaged. Each subject's error in perception of weightbearing at each target level was determined by taking the absolute value of the target percent weightbearing minus the mean actual percent weightbearing. The mean errors at the 25, 50, and 75% targets were 7.3, 3.3, and 7.7%, respectively. The magnitude of the error was unrelated to age. An analysis of variance showed that error was not dependent on sex or whether the dominant lower extremity was used for making judgements. The error did differ between target levels. Clinicians cannot assume, based on the findings of this study, that individuals can accurately judge the percent weightbearing they are placing through one of their lower extremities during bilateral upright stance.

Adult↗