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Biomedical subjects

K M Berg

Publications and source records attributed to K M Berg.

7 recordsLinked to original sources
PubMed1995

Temporal summation of 500-Hz tones and octave-band noise bursts in infants and adults.

A visually reinforced operant procedure was employed to obtain 2-point threshold-duration functions in 7-month-old infants and adults in two experimental paradigms. In Experiment 1, thresholds were determined for 10- and 100-msec, 500-Hz tones and octave-band noise bursts presented in quiet and noise backgrounds. Threshold-duration functions were significantly steeper for infants than for adults under all experimental conditions, and did not differ in slope as a result of differences in either stimulus bandwidth or masking noise. In Experiment 2, thresholds for trains of brief 500-Hz tone pulses were examined in infant and adult subjects. Infant functions were adult-like for integration of multiple-pulse stimuli, suggesting that the traditional, long-term process of temporal summation is mature by 7 months of age. Differences between the present results and those previously obtained for 4-kHz stimuli appear to be consistent with the view that different mechanisms are involved in the detection of low- and high-frequency signals.

Adult↗
PubMed1995

Physiological responses to in-line skating compared to treadmill running.

The physiologic responses to in-line skating were compared to those during treadmill running in 16 active males (18-37 yr). Each subject performed a VO2max test during in-line skating and treadmill running using speed-incremented, discontinuous protocols. Protocols were designed so that each subject completed 4-6 stages. Stages were 3 min in duration and separated by a 5-min rest period. It was found that absolute VO2max (4.19 vs 4.44 l.min-1, P = 0.045), relative VO2max (56.8 vs 59.9 ml.kg-1.min-1, P = 0.054), and HRmax (189 vs 194 b.min-1, P < 0.05) were lower for in-line skating compared to treadmill running. Regression analyses were used to determine the submaximal relationship between modalities. There were no significant (P > 0.05) differences in the slope and y-intercept of the HR/VO2 relationship, indicating a similar metabolic load at a given heart rate for both modes of exercise. Skating between 17.7-20.9 km.h-1 corresponded to 60-75% of VO2max or 75-90% of HRmax, which are common training intensities and within the guidelines recommended by the ACSM. Across the speeds investigated, caloric expenditure was 9.5-19.0 kcal.min-1. These results indicate that in-line skating elicits physiological responses comparable to treadmill running and thus would be another exercise alternative for improving aerobic capacity or maintaining body weight.

Adult↗
PubMed1993

A comparison of thresholds for 1/3-octave filtered clicks and noise bursts in infants and adults.

Behavioral thresholds of 6-month-old infants and adults were determined for 1/3-octave filtered clicks and 300-msec noise bursts with center frequencies ranging from .5 to 8 kHz. For noise bursts, differences between infant and adult thresholds were largest at low frequencies and smallest at 8 kHz. For clicks, infants' thresholds were most like adults' at 4 kHz, and age differences increased at both lower and higher frequencies. Differences between click and noise thresholds were significantly larger for infants than for adults at .5, 1, and 8 kHz, but not at 2 and 4 kHz. These results suggest that improvements in threshold for long-duration stimuli during infancy may not be accompanied by comparable changes in threshold at short durations. The delayed development of sensitivity to low- and high-frequency clicks appears consistent with maturational trends recently described for the auditory brainstem response.

Acoustic Stimulation↗
PubMed1991

Auditory temporal summation in infants and adults: effects of stimulus bandwidth and masking noise.

A visually reinforced operant procedure was employed to determine the behavioral thresholds of 6- to 7-month-old infants and adults for stimuli of various bandwidths and durations. Experiment 1 compared absolute thresholds for broadband and 1/3-octave filtered clicks and 300-msec noise bursts. For adult subjects, the difference in threshold for clicks and noise bursts was quite comparable in the two bandwidth conditions, but infants' click-noise threshold differences were significantly larger for broadband than for 1/3-octave stimuli. In Experiment 2, 2-point threshold-duration functions were compared for 4-kHz tones and octave-band noise bursts presented in backgrounds of quiet and continuous noise. Infants' threshold-duration function for octave-band noise bursts was significantly steeper than the comparable adult function in quiet, but not in masking noise. These results suggest that young infants may have particular difficulty detecting low-intensity broadband sounds when durations are very short.

Adult↗
PubMed1983

Behavioral thresholds for tones during infancy.

An adaptive up-down tracking procedure was used in combination with a visually reinforced head turn response to examine auditory sensitivity for 500, 2000, and 8000-Hz tone bursts in infants 6 to 18 months of age. Six- and 10-month-old infants were tested with headphone presentation of stimuli, while 10-, 14-, and 18-month-olds were tested in sound field. Infant threshold estimates for both headphone and sound field were within 15 dB of adult comparisons for all frequencies and age groups. Six-month-olds were significantly less sensitive to the 8000-Hz tone than to either of the lower frequency stimuli, but older infants demonstrated approximately equal sensitivity for all three frequencies tested.

Age Factors↗