Dieter Wolke

The cognitive outcome of very preterm infants may be poorer than often reported: an empirical investigation of how methodological issues make a big difference.

The effects of relying on outmoded IQ-test norms and the use of arbitrary classifications of developmental delay on estimates of cognitive impairment of very preterm infants (VPI) was evaluated in a prospective population study. Cognitive assessments included the Griffiths test at 5 and 20 months and the Columbia Mental Maturity Scales (CMM) and a vocabulary test (Aktiver Wortschatz Test, AWST) at 56 months of age. Rates of cognitive impairment of 321 very preterm infants (VPI; <32 weeks gestation or <1500 g birth weight) were determined according to the published test norms, to scores of a full-term control group (FCn=321), and to scores from a representative sample of children (NCn=431) of the same birth cohort. IQ-scores were higher in the FC and NC children than in the original standardisation sample (SS). Using the concurrent test norms (FC, NC) up to 2.4 times more VPI were identified as seriously impaired (<−2 SD) than if the published (outdated) norms were used. Serious developmental delay was underestimated when arbitrary (e.g. DQ<70) rather than across age comparable definitions (DQ<−2 SD) were used. VPI study drop-outs had mothers with lower educational qualifications and poorer cognitive developmental scores at 5 or 20 months of age. In conclusion, a lack of appropriate control groups and use of arbitrary criteria for judging serious delay leads to large underestimations of cognitive impairment in VPI. Findings from previous uncontrolled studies of VPI need re-interpretation.

The objective rating of oral-motor functions during feeding

The Schedule for Oral Motor Assessment (SOMA) was developed to record oral-motor skills objectively in infants between ages 8 and 24 months postnatal. Its aim is to identify areas of dysfunction that could contribute to feeding difficulties. The procedure takes approximately 20 min to administer, and is intended to be rated largely from a videorecording of a structured feeding session. A series of foodstuffs of varying textures, including liquids, is presented to the child in a standardized manner. Oral-motor skills are evaluated in terms of discrete oral-motor movements. The schedule distinguishes these from skills at more aggregated levels of functioning such as jaw, lip, and tongue control. A total of 127 children have been studied with the instrument, including normal healthy infants and samples with nonorganic failure to thrive, and cerebral palsy. Interrater and test-retest reliabilities were determined on a subset of 10 infants who each took part in three trials rated by 2 therapists. Excellent levels of interrater reliability (kappa >0.75) were obtained for the presence/absence of 69% of discrete oral-motor behaviors. Test-retest reliability was similarly excellent for 85% of ratable behaviors. For the first time an assessment of oral-motor functioning has been shown to have adequate reliability for children aged 8–24 months. The validation of the SOMA on a large sample of normally developing infants and its application to clinical groups is presented in an accompanying paper [1].

Validity of the crying pattern questionnaire in a sample of excessively crying babies

Abstract A short and simple questionnaire for the assessment of duration and bouts of fussing and crying behaviour in infants, the Crying Pattern Questionnaire (CPQ), was compared with a 7-day 24 hour systematic diary record. Moderate to good convergence between maternal reports in the CPQ and the diary were found for duration of fuss/cry behaviour. The convergences were lower but highly significant for reports of the number of bouts of crying in 24 hours. Slightly poorer agreement was also found when mothers reported that the infants had large variations in the day to day amounts of fussing and crying. The total amount of fussing and crying was overestimated by the mothers in the CPQ relative to the diary by 13%. The data support that the CPQ may be a useful instrument for large scale community surveys of the prevalence of excessive crying.

Oral‐motor dysfunction in children who are failing to thrive

A whole population prospective survey of inner-city infants (N=2510), aged from birth to 15 months, found the prevalence of failure to thrive (FTT), unassociated with any medical aetiology, to be 3.3%. A speech therapist, blind to case status, used the Schedule for Oral Motor Assessment (SOMA) to rate abilities across a range of food textures and fluids. One in four FTT cases, but only 11% of comparisons, obtained dysfunction scores outside the normal range. Most difficulty was observed with purees, least with liquids. Oral-motor dysfunction did not simply reflect developmental delay. SOMA scores did not correlate with either the mental or psychomotor index of the Bayley Scales of Infant Development (BSID), but did correlate negatively with birth weight (r=−0.3, p<0.01); weight at 3 months (r=−0.28, p<0.003); 6 months (r=−0.3, p<0.01); and 9 months (r=−0.28, p<0.02), but not with weight at follow up. Children with the highest dysfunction scores weighed least at all ages and had smaller head circumferences. High oral-motor dysfunction scores were not linked to overt feeding difficulties, by maternal report. It was hypothesised that the disorder reflects the influence of early post-natal growth failure (presumably due to undernutrition) upon developing brain structures, rather than a congenital abnormality.