Kathleen M. Berg

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.

The Ratio between Positive and Negative Affect and Flourishing Mental Health across Adulthood

Using data from a 30-day diary study with 239 adults (81 young, 81 middle-aged, and 77 older adults), this study examined whether a specific ratio between positive and negative affect distinguished individuals with different mental health status and especially flourishing from non-flourishing individuals. In addition, the study addressed whether there were age differences in the positivity ratio when daily affect data were used, and whether the proposed critical positivity ratio of 2.9 discriminated equally well between individuals with different mental health status across the adult lifespan. Findings showed that the ratio of positive to negative affect differed across adulthood such that age was associated with an increasing preponderance of positive to negative affect. The positivity ratio was also associated with mental health status in the hypothesized direction; higher positivity ratios were associated with better mental health. Finally, although the data supported the notion of a positivity ratio of 2.9 as a ‘critical value’ in young adulthood, this value did not equally well discriminate the mental health status of middle-aged and older adults.

Expression of Interleukin‐22 in Sjögren’s Syndrome: Significant Correlation with Disease Parameters

Sjögren’s syndrome (SS) is an autoimmune disease targeting the exocrine glands resulting in xerostomia/keratoconjunctivitis sicca. Presently, we examined the levels and clinical correlations of IL‐22 in SS. Patients with SS together with normal controls were randomly selected. IL‐22 was detected at significantly higher levels in sera of patients with SS. The levels of IL‐22 present in sera showed statistically significant direct correlations with hyposalivation, anti‐SSB, anti‐SSA/SSB combined, hypergammaglobulinemia and rheumatoid factor. IL‐22 showed a direct correlation with major clinical parameters. The data suggest that IL‐22 plays a critical role in the development of SS, and further study is needed to examine its function in human SS.

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-octavefiltered 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.

Labial salivary gland biopsies in Sjögren's syndrome: still the gold standard?

OBJECTIVES The accuracy and diagnostic benefits of the labial salivary gland (LSG) biopsy for Sjögrens syndrome (SS) have received mixed reviews. This study was conducted to assess (1) the inter-rater agreement among 5 pathologists, and (2) the relationship between biopsy findings and clinical disease parameters. STUDY DESIGN Three oral pathologists (OP) and two surgical pathologists (SP) provided independent diagnoses, focus scores, and plasma cell characterizations for 37 LSG biopsies. Inter-rater reliability was assessed using percentage of overall agreement and intraclass correlation coefficients. Relationships between diagnoses and clinical parameters were assessed by nonparametric correlations. RESULTS Overall agreement among the pathologists was poor, although the intra-specialty agreement was good. The ratings of OP were most highly correlated with serological measures, while those of SP were correlated with salivary flow rate and disease damage. CONCLUSION Since the LSG biopsy can be the determining factor in SS diagnoses, these demonstrated inconsistencies merit further consideration.

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.

Noise increment detection in children 1 to 3 years of age.

Studies using burst comparison procedures to examine age-related changes in intensity discrimination have reported that the ability to discriminate differences in intensity does not reach maturity until late childhood. In the present study, developmental changes in intensity discrimination were examined in 1- to 3-year-old children, using an increment detection paradigm. Children and adults detected increments in a continuous standard presented at three levels ranging from 35 to 55 dB SPL. Adults were also tested at lower levels of the standard in order to permit age comparisons at equivalent sensation levels. Standard stimuli were two-octave bands of noise centered at either 400 or 4000 Hz, and increments were 200 msec in duration. Discrimination performance improved significantly with both age and level of the standard. For all age groups, performance was significantly better for high- than for lowfrequency stimuli, but frequency-dependent differences in increment thresholds did not vary reliably with age. Age differences were largest at low levels of the standard. At the highest level (approximately 30 dB nHL), children’s difference limens for both low- and high-frequency noise bands were adultlike by 3 years of age. These results suggest that the developmental time course of increment detection is more rapid than that previously reported in burst comparison studies.

Infants’ detection of increments in low- and high-frequency noise

A visually reinforced operant paradigm was employed to examine the relationship between the difference limen (DL) for intensity and level of the standard during infancy. In Experiment 1,7-month-old infants and adults detected increments in continuous noise presented via headphones at each of four levels ranging from 28 to 58 dB SPL. Noise stimuli were 2-octave bands centered at either 400 or 4000 Hz, and increments were 10 and 100 msec in duration. Infants’ DLs were significantly larger than those of adult subjects and significantly larger for low- than for high-frequency stimuli. For the high-frequency noise band, infants’ DLs were generally consistent with Weber’s law,remaining essentially constant for standards higher than 28 dB SPL (3 dB SL) for 100-msec increments and 38 dB SPL (13 dB SL) for 10-msec increments. For low-frequency noise, infants’ absolute thresholds were exceptionally high, and sensation levels of the standards were too low to adequately describe the relationship. In Ex-periment 2, 7-month-old infants detected 10- and 100-msec increments in 400-Hz noise stimuli presented in sound field. Infants’ low-frequency DLs were large at low intensities and decreased with increases in level of the standard up to at least 30 dB SL. For both low- and high-frequency noise, the difference between DLs for 10- and 100-msec increments tended to be large at low levels of the standard and to decrease at higher levels. These results suggest that the relationship between the DL and level of the standard varies with both stimulus frequency and duration during infancy. However, stimulus-dependent immaturities in increment detection may be most evident at levels within approximately 30 dB of absolute threshold.

Frequency recognition in temporal interference tasks: A comparison among four psychophysical procedures

The frequency discrimination of a 20-msec test tone was measured for the same subjects in four psychophysical paradigms: a single-interval procedure, a two-alternative forced-choice procedure, a same-different procedure, and a method-of-adjustment procedure. In each paradigm, the 20-msec test tone was preceded or followed by a 500-msec, 800-Hz interfering tone. The interfering tone occurred 50 or 5 msec before the onset of the test tone (forward interference) or 100 or 5 msec after the offset of the test tone (backward interference). In each of the four paradigms and for each of the interference conditions the value of Δf for the test tone was varied symetrically around 800 Hz to obtain an estimate of the frequency discrimination thresholds. In all psychophysical paradigms except for the single-interval procedure, there were small or no significant differences in observers’ frequency discrimination behavior among the interference conditions. The thresholds for Δf from these conditions were approximately the same as those obtained without an interfering tone. In the single-interval task, when the test tone preceded the interfering tone (backward interference) by 5 msec, an increase in the value of Δf required for discrimination over that required in the other conditions was measured. These results suggest that the effect of backward interference on a target tone does depend on psychophysical procedure.

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.