In experimental models, prenatal cocaine exposure has been found to perturb monoaminergic development of systems implicated in modulating attention. To determine whether prenatal cocaine exposure affects infant attention, we assessed visual recognition memory and focused attention during free play. We enrolled at birth 380 infants, 113 cocaine exposed, using multiple biomarkers to assess drug exposure. Behavior was videotaped and coded off-line for sustained looking time (i.e. focused attention), banging and intrusion. Prenatal cocaine exposure was not associated with visual recognition memory, but was significantly associated with longer sustained looking times (average focused attention) at ages 6 months (p = 0.02) and 12 months (p = 0.04) in analyses that adjusted for variables, including maternal intelligence, education, depressive scores and other exposures (alcohol, tobacco and marijuana). Cocaine-exposed infants at age 12 months also spent significantly less time in banging activity (p = 0.02) after adjusting for confounding variables. This finding was not explained through cocaine effects on motor development, neurological findings or time spent in focused attention. Prenatal cocaine exposure was significantly associated with longer periods of sustained looking or focused attention in infancy, a finding that could interpreted as a measure of poor processing efficiency, or alternatively as precocious maturation of attentional systems. Either interpretation has implications for later cognitive development. Lower banging activity among cocaine exposed was not explained through cocaine effects on motor development or neurological findings, suggesting that activity level itself is diminished in these infants. Whether focused attention findings impact long term development awaits further study.

SYNOPSIS Investigations were undertaken to discover the effect and importance of technical factors in the Guthrie test and to determine the most satisfactory materials available.These findings were used in setting up the screening service for phenylketonuria for the South West Metropolitan Region.The Medical Research Council Working Party on phenylketonuria (1968) recommended that the Guthrie test should be adopted on a national scale to replace the Phenistix test as a screening procedure for phenylketonuria.Recent evidence (Hudson, Mordaunt, and Leahy, 1970) has confirmed the value of early dietetic treatment and the need for early diagnosis, and Guthrie test services are being developed in most parts of the United Kingdom. This test has been in routine use for three years in this laboratory which deals with 50,000 specimens yearly for the South West Metropolitan Region.The experience gained in the early pilot studies with the Guthrie test and subsequently in developing a regional service is presented here from a laboratory point of view. Investigations were undertaken to discover the effect and importance of factors which influenced the test and to determine the best materials to use. Administrative problems are outside the scope of this paper and are discussed in a separate publication. Colection CardsBlood samples are collected from babies by heel prick and absorption of the blood onto specially prepared blotting paper. Several printed commercial collection papers are available and range from simple cut papers to those made into pads with interleaved carbon paper for recording details. Most of those examined were expensive and unnecessarily complicated. The sequential numbering available on some seemed of little value when cards were to be returned randomly from numerous centres. Cards with carbon paper proved unsatisfactory as handling made the samples very dirty.

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