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Biomedical subjects

H Naylor

Publications and source records attributed to H Naylor.

24 records · Page 2Linked to original sources
PubMed1980

Lateral asymmetry in perceptual judgments of reading disabled, hyperactive and control children.

Three groups of 11 year old boys, classified as reading-disabled/hyperactive, hyperactive, and normal controls, made same-different judgments to pairs of verbal or visuospatial stimuli presented simultaneously to the right or left side of a fixation point. Two experimental paradigms were used, one emphasizing comparison judgments from memory, the other, new comparison judgments. Reading-disabled boys made more errors of judgment than did controls. All subjects exhibited faster reaction times for different judgments of pairs appearing in the left visual field. Reaction times were longer and errors more numerous for judgments made when two stimuli were presented simultaneously, one to each visual field. Differences in performance for the two halves of the visual field are attributed to memory storage effects for overlearned stimuli. The deficiency in interhemispheric comparisons is attributed to immaturity of the cerebral commissures. The reading-disabled group appears to encompass two subgroups with differing modes of information processing.

Child↗
PubMed1977

A comparison of methods for quantitating fetal heart rate variability.

Fetal heart rate (FHR) variability is thought to be an important index of fetal health. In the presence of normal variability, the fetus is vigorous, but lack of beat-to-beat variability may be associated with fetal compromise. A distinction between short-term variability (STV) (beat-to-beat changes between successive beats) and long-term variability (LTV) (rhythmic fluctuations in FHR) has not been made to date. We have utilized computer programs to compare three pairs of mathematical indices and one visual index of FHR variability. Among the three pairs of indices designed for detection of STV and LTV, de Haan's short-term and long-term indices exhibited the least interdependence, and the long-term index was completely insensitive to artifically generated pure STV. Yeh's short-term and long-term indices exhibited substantial positive interdependence. Hon's visual index appears to detect LTV primarily rather than STV. When the effect of progression of labor on FHR variability was examined, no conclusions were possible because of inconsistencies between patients. Ultimately, the clinical value of any one of these indices awaits testing of their ability to define fetal well-being or fetal distress.

Analog-Digital Conversion↗
PubMed1977

Very short-term memory dysfunction in schizophrenia. Defective short time constant information processing in schizophrenia.

Disordered, very short-term memory (VSTM) has been hypothesized as the fundamental cognitive deficit in schizophrenia. We describe a method that measures VSTM using self-stimulated auditory average evoked potentials. This paradigm allows the VSTM hyothesis to be tested relatively free of superficial attentional and motivational artifacts. The experimental results are consistent with a VSTM dysfunction in schizophrenia. Very short-term memory dysfunction is discussed in light of recent blink reflex evidence that there is a short time constant information processing system with a time base similar to VSTM (ie, 1 to 1,000 msec). This leads to new testable hypotheses about information processing and VSTM in schizophrenia. It also lays the basis for interpreting this phenomenon as a pathologic exaggeration of an adaptive neurophysiologic mechanism.

Adaptation, Psychological↗