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Biomedical subjects

V T Wynn

Publications and source records attributed to V T Wynn.

11 recordsLinked to original sources
PubMed1993

Accuracy and consistency of absolute pitch.

The accuracy and consistency of absolute pitch (AP) judgments have been measured on three subjects in two longitudinal studies separated by twenty years. The drifts and cyclical variations observed in the earlier study still persisted, and an investigation of two other subjects, one of whom was first studied forty years ago, suggests that they might undergo similar cyclical variations in their pitch perception. Pitch judgments also varied during the day. The detailed observations of these nonrandom fluctuations have been used to determine a value for the underlying consistency of the AP estimates. When the effects of the daytime variations and longer-term drifts were removed, the values for this consistency, as measured by the standard deviation, were calculated to be 3.1, 3.4, 3.7, 4.4, and 4.5 Hz for the five subjects. When an oscillator was used to produce the estimate, the consistency of the judgments was observed to depend on the accuracy of those judgments.

Acoustic Stimulation↗
PubMed1992

Absolute pitch revisited.

The absolute pitch ability (AP) of three female and two male subjects has been investigated over many years. The pitch estimates of A4 (440 Hz) of four of the subjects varied by up to a semitone during the longitudinal study. The fifth subject showed no noticeable variation in his estimates of A4. Standard deviations calculated from the data showed no significant variation with age.

Adult↗
PubMed1992

Normal relation between heart rate and cardiac repolarisation in sudden infant death syndrome.

OBJECTIVE: To determine whether there was a difference in the relation between heart rate and RT intervals in infants who later died of sudden infant death syndrome (SIDS) and controls. DESIGN: A blinded, computer analysis of prospectively acquired physiological data on SIDS cases and controls. SETTING: Physiological data obtained from infants at home (collaborative analysis National Heart and Lung Institute and Exeter University). PARTICIPANTS: Nine fullterm infants who subsequently died of SIDS and 10 surviving controls matched for age and birth weight. INTERVENTIONS: 24 hour tape recordings of the electrocardiogram at home between three and 11 weeks of age. MAIN OUTCOME MEASURES: Mean value of the constant b, which relates by linear regression the log of each RT interval to the log of its proceeding RR interval, and any difference between SIDS cases and controls. RESULTS: The mean (2SEM) values for b were 0.20 (0.03) for the 10 controls and 0.19 (0.03) for the nine SIDS infants. Cyclical correlations between RT and RR intervals of varying strength were identified in both SIDS infants and controls. CONCLUSIONS: Infants who subsequently died of SIDS did not show an impaired ability to modify RT intervals in response to change in heart rate.

Electrocardiography↗
PubMed1988

Effect of melatonin on the human electrocardiogram and simple reaction time responses.

It has been suggested that melatonin may have therapeutic potential for alleviating jet lag. In an attempt to define further the effects of low pharmacological doses of melatonin on the human body, 5 mg of melatonin was given orally to one subject in a blind experiment. The electrocardiogram (ECG) was recorded together with simple reaction time (SRT) responses over a 5-h period after taking melatonin. The main part of the project was carried out under artificial domestic lighting conditions and involved ten evening sessions. Microprocessor analysis of the ECG of one subject clearly showed that melatonin had the effect of lengthening the RR interval, that between the peak of the P wave and the onset of the R wave, and the interval between the onset of the R wave and the peak of the T wave. A model to explain the cubic curve, which was fitted by regression analysis to the data, implies that the natural evening increase in melatonin may also increase these intervals. The results suggest that melatonin may affect both the phase and the amplitude of the observed ECG phenomenon. Analysis of more than 40,000 SRT responses to both visual and auditory stimuli implied that these responses might also be lengthened by melatonin. Frequency histograms of the responses and observations on premature and missed responses were not able to reproduce the results of other workers who found that higher doses (240 mg) of melatonin decreased the number of incorrect responses to simple reaction time tasks.

Acoustic Stimulation↗
PubMed1986

Heart rate dependence of the RT interval in the first month of life.

Computer analysis of more than 100 000 RT and RR intervals obtained from 70 babies spanning the age range 2-75 d indicates that the RR-RT relation cannot be characterised by any general formula during the first month of life. The babies included 22 sudden infant death syndrome (SIDS), 22 matched controls and 26 normal infants. RT intervals were corrected for RR variation for each baby using linear regression analysis. The corrected RT interval was observed to increase sharply during the first month of life for each group of babies. The similarity in the results for all three groups suggest that an investigation of the RT interval will contribute very little, if anything, to a SIDS investigation.

Electrocardiography↗
PubMed1980

Reaction time as a function of the cardiac cycle.

Simple reaction times to auditory stimuli varied with the phase of the cardiac cycle in which the stimulus was presented. Longitudinal studies showed that stimuli triggered at different phases in the ECG gave rise to different rhythmic patterns of behaviour.

Circadian Rhythm↗
PubMed1972

Measurements of small variations in 'absolute' pitch.

1. Longitudinal studies on absolute pitch estimates have been observed in one male and two female subjects.2. The female subjects underwent rhythmic variations in their estimates that were related to their menstrual cycles. One female subject, the more intensively studied of the two, also showed variations in her pitch estimates that were related to illness.3. Relevant correlations between the menstrual cycle and known biochemical parameters are mentioned which suggest that the fluctuations in the female estimates are governed by changes in the electrical activity of the auditory nervous system.4. The male subject showed similar fluctuations in his pitch estimates. A rhythm of approximately 20 days was observed.5. A connexion between the fluctuations in the pitch estimates and the sex hormones in both the female and the male subjects is suggested as a possible explanation of the difference between two different types of absolute pitch.6. The hypothesis is extended to show how the adrenal corticosteroids could account for the changes in the pitch estimates that occurred with illness.

17-Ketosteroids↗