Dianne McCarthy

Antenatal exposure to betamethasone: psychological functioning and health related quality of life 31 years after inclusion in randomised controlled trial

Abstract Objectives To determine if antenatal exposure to betamethasone for the prevention of neonatal respiratory distress syndrome alters psychological functioning and health related quality of life in adulthood. Design Follow-up of the first and largest double blind, placebo controlled, randomised trial of a single course of antenatal betamethasone for the prevention of neonatal respiratory distress syndrome. Setting Tertiary obstetric hospital in Auckland, New Zealand. Participants 192 adult offspring, mean age 31 years, of mothers who took part in a randomised controlled trial of antenatal betamethasone for the prevention of neonatal respiratory distress syndrome (87 exposed to betamethasone and 105 exposed to placebo). Interventions Mothers received two doses of betamethasone or placebo 24 hours apart. Main outcome measures Cognitive functioning assessed with Wechsler abbreviated scale of intelligence; working memory and attention assessed with Benton visual retention test, paced auditory serial addition test, and Brown attention deficit disorder scale; psychiatric morbidity assessed with Beck depression inventory II, state-trait anxiety inventory, and schizotypy traits questionnaire; handedness assessed with Edinburgh handedness inventory; health related quality of life assessed with short form 36 health survey. Results No differences were found between groups exposed to betamethasone and placebo in cognitive functioning, working memory and attention, psychiatric morbidity, handedness, or health related quality of life. Conclusions Prenatal exposure to a single course of betamethasone does not alter cognitive functioning, working memory and attention, psychiatric morbidity, handedness, or health related quality of life in adulthood. Obstetricians should continue to use a single course of antenatal betamethasone for the prevention of neonatal respiratory distress syndrome.

Psychological functioning and health-related quality of life in adulthood after preterm birth.

The aim of this study was to determine if preterm birth is associated with socioeconomic status (SES), psychological functioning, and health‐related quality of life (HRQoL) in adulthood. We used prospective follow‐up of 192 adult offspring of mothers who took part in a randomized controlled trial of antenatal betamethasone for the prevention of neonatal respiratory distress syndrome (66 born at term [33 males, 33 females] 126 born preterm [66 males, 60 females]). Cognitive functioning was assessed using the Wechsler Abbreviated Scale of Intelligence. Working memory and attention was assessed using the Benton Visual Retention Test, the Paced Auditory Serial Addition Test, and the Brown Attention Deficit Disorder Scale. Psychiatric morbidity was assessed using the Beck Depression Inventory II, the State‐Trait Anxiety Inventory, and the Schizotypy Traits Questionnaire. Handedness was assessed using the Edinburgh Handedness Inventory. HRQoL was assessed using the Short Form‐36 Health Survey. Moderately preterm birth (median gestation 34wks, mean birthweight 1946g [SD 463g]) was not related to later marital status, educational attainment, SES, cognitive functioning, working memory, attention, or symptoms of anxiety or schizotypy at 31 years of age. Preterm birth was associated with fewer symptoms of depression and higher levels of satisfaction in three of the eight HRQoL domains measured (bodily pain, general health perception, and social functioning). Adults who were born moderately preterm have SES, psychological functioning, and HRQoL consistent with those who were born at term. This good long‐term outcome cannot be extrapolated to those with early childhood disability or very low birthweights.

Isobias and alloiobias functions in animal psychophysics.

An analogue of the human yes-no detection task was used to train six pigeons to discriminate luminance differences under two different reinforcer-scheduling procedures. When a controlled reinforce-ratio procedure was used, relative stimulus frequency was constant at .5, and relative reinforcer frequency for correct detections was held constant at three different values for each of five luminance differences. When an uncontrolled reinforcer-ratio procedure (the typical detection paradigm) was used, relative reinforcer frequency for correct detections was allowed to covary with changes in relative stimulus frequency for each of five luminance differences. Two measures of bias, response bias (Davison & Tustin, 1978) and the detection-theory likelihood-ratio measure (beta obt), were compared. The controlled reinforcer-ratio procedure generated equal- or iso-response-bias functions, and the uncontrolled reinforcer-ratio procedure gave changing or alloio-response-bias functions. The Davison-Tustin model accounted for 88% and 93% of the data variance in the controlled and uncontrolled reinforcer-ratio procedures, respectively. The best-fitting equal-beta functions accounted for an average of 53% and 69%, respectively, in the two procedures. In addition, neither procedure gave constant measures of beta obt for constant bias manipulations across different discriminability measures.

Towards a behavioral theory of bias in signal detection

A behavioral model for performance on signal-detection tasks is presented. It is based on a relation between response and reinforcement ratios which has been derived from both animal and human research on the distribution of behavior between concurrently available schedules of reinforcement. This model establishes the ratio of obtained reinforcements for the choice responses, and not the probability of stimulus presentation, as the effective biaser in signal-detection research. Furthermore, experimental procedures which do not control the obtained reinforcement ratio are shown to give rise to unstable bias contours. Isobias contours, on the other hand, arise only from controlled reinforcement-ratio procedures.

Reinforcer frequency and reinforcer duration as biasers of signal detection

Five pigeons were trained to discriminate a constant luminance difference when both reinforcer frequency and reinforcer magnitude were varied in an animal analogue of the human discrete-trial yes- no detection task. Variation of relative reinforcer frequency was more effective in biasing detection performance than variation of relative reinforcer duration. Stimulus discriminability was independent of both reinforcer frequency and reinforcer duration.