The effectiveness of preschool vision screening by health visitors.

The aim of this study was to determine the effectiveness of preschool vision surveillance by health visitors in Warrington, a district with a secondary community orthoptic service. Of the 2041 children screened by health visitors at 3-3 1/2 years 12% were referred to the orthoptist for further assessment. Sixty-three per cent of these required more than one examination by the orthoptist and 28% were subsequently referred to an ophthalmologist for further assessment. Amblyopia was detected in 11 children, 5 had squints without amblyopia, and in addition 25 children had significant refractive errors. A retrospective review of the records of children identified with amblyopia following a school entry medical at 5 years was undertaken to detect possible failure of the earlier health visitor examination (i.e. false negatives at age 3-3 1/2 years). Possible failure of early screening was found in only two children, one of whom had a minor defect only (6/9). Vision screening for children aged 3-3 1/2 years by health visitors is an effective alternative to primary screening by orthoptists. However, the use of health visitors in this role is contrary to current national guidelines. The findings suggest that using health visitors to screen vision in preschool children makes efficient use of existing routine checks and may be the best use of orthoptic time.

Integrality of nasalization and F1. II. Basic sensitivity and phonetic labeling measure distinct sensory and decision-rule interactions.

In vowel perception, nasalization and height (the inverse of the first formant, F1) interact. This paper asks whether the interaction results from a sensory process, decision mechanism, or both. Two experiments used vowels varying in height, degree of nasalization, and three other stimulus parameters: the frequency region of F1, the location of the nasal pole/zero complex relative to F1, and whether a consonant following the vowel was oral or nasal. A fixed-classification experiment, designed to estimate basic sensitivity between stimuli, measured accuracy for discriminating stimuli differing in F1, in nasalization, and on both dimensions. A configuration derived by a multidimensional scaling analysis revealed a perceptual interaction that was stronger for stimuli in which the nasal pole/zero complex was below rather than above the oral pole, and that was present before both nasal and oral consonants. Phonetic identification experiments, designed to measure trading relations between the two dimensions, required listeners to identify height and nasalization in vowels varying in both. Judgments of nasalization depended on F1 as well as on nasalization, whereas judgments of height depended primarily on F1, and on nasalization more when the nasal complex was below than above the oral pole. This pattern was interpreted as a decision-rule interaction that is distinct from the interaction in basic sensitivity. Final consonant nasality had little effect in the classification experiment; in the identification experiment, nasal judgments were more likely when the following consonant was nasal.

Integrality in the perception of tongue root position and voice quality in vowels.

In English and a large number of African and Southeast Asian languages, voice quality along a tense-lax dimension covaries with advancement of the tongue root in vowels: a laxer voice quality co-occurs with a more advanced tongue root. As laxing the voice increases energy in the first harmonic relative to higher ones and advancing the tongue root lowers F1, the acoustic consequences of these two articulations may integrate perceptually into a higher-level perceptual property, here called spectral "flatness." Two Garner-paradigm experiments evaluated this interaction across nearly the entire range of tense-lax voice qualities and a narrow range of F1 values. The acoustic consequences of laxness and advanced tongue root integrated into spectral flatness for tenser and laxer but not for intermediate voice qualities. Detection-theoretic models developed in earlier work proved highly successful in representing the perceptual interaction between these dimensions.

Neonatal neurologic examinations of very preterm infants: comparison of results with ultrasound diagnosis of periventricular hemorrhage.

Seventy infants born before 33-weeks gestation were studied by serial ultrasound brain scans from the first days of life; twenty had periventricular hemorrhage (PVH). Weekly neurologic examinations were performed from age 5 to 10 days. Only measures of passive tone could be elicited before an age equivalent to 34-weeks gestation because the infants were very sick, and many were receiving treatment with mechanical ventilation. Gestation was the most important determinant of this aspect of neurologic functioning, and no effect of time from birth was noted. Before ages equivalent to 34-weeks gestation, no significant relationship was found between measures of passive tone, including the size of the popliteal angle, and PVH diagnosed by ultrasound. At ages equivalent to 34 weeks or more, measures of active as well as passive tone and reflexes were consistently elicited. No single measure discriminated between infants with or without PVH, but serial observations indicated that persisting imbalance of active tone and clonus were only noted in infants with PVH, including 7 of the 8 infants who had PVH complicated by ventricular enlargement. It was concluded that neurologic examination does not reliably diagnose PVH during the neonatal period in sick, very preterm infants. At an age equivalent to term, it may help to distinguish infants who sustained permanent brain damage in association with neonatal PVH which may lead to adverse sequelae at follow-up.

Ultrasound appearance of the brain in very preterm infants and neurodevelopmental outcome at 18 months of age.

The brains of 158 consecutively admitted very preterm infants were repeatedly examined with real time ultrasound. Abnormalities, most commonly periventricular haemorrhage, were detected in 79 (50%). The 109 infants who survived were followed up until they were 16-23 months old. Major or minor neurological or developmental sequelae were found in 5 of 62 infants (8%) with normal ultrasound scans and in an identical proportion, 2 of 25 infants (8%), with uncomplicated periventricular haemorrhage. By contrast, 15 of 21 infants (71%) whose ventricles became enlarged (with or without periventricular haemorrhage) had abnormalities at follow up. The proportion with sequelae depended on the cause and extent of the enlargement. Three of 8 infants (38%) with mild (usually transient) ventricular distension had sequelae, compared with 3 of 4 (75%) with hydrocephalus and 9 of 9 (100%) with cerebral atrophy (2 of whom also had hydrocephalus). Adverse neurodevelopmental sequelae at follow up appeared more often to be attributable to cerebral ischaemia and infarction than to periventricular haemorrhage.

Timing and antecedents of periventricular haemorrhage and of cerebral atrophy in very preterm infants.

The brains of 95 consecutively admitted infants born at less than 33 weeks gestation were scanned with ultrasound. Thirty-six (38%) had periventricular haemorrhage (PVH). Eight (8%) had cerebral atrophy (together with PVH in 5). Twelve (40%) of the 30 infants in whom satisfactory timing of PVH was possible bled on the first day of life, but the median age when PVH was first detected was during the second day. The median age when PVH reached its maximum extent was the fourth day. The most significant antecedents of PVH were very short gestation and the presence of severe respiratory illness, particularly hyaline membrane disease, necessitating mechanical ventilation. Analysis of variance showed that pneumothorax arising during ventilation was the single most significant antecedent of PVH. Other significant antecedents, notably prolonged coagulation times, were found almost exclusively in infants with severe respiratory illness. Cerebral atrophy appeared usually to be attributable either to severe asphyxia during delivery or later, or to the formation of cysts at the site of previous haemorrhage into brain tissue.

Accuracy of imaging of the brains of newborn infants by linear-array real-time ultrasound.

Comparisons were made in 69 newborn infants of the appearance of the brain as visualised by linear-array real-time ultrasound, computerised tomography and at autopsy, in order to evaluate the accuracy of ultrasound for the detection of lesions in the brain. Ultrasound was found to give a good estimate of the presence and extent of haemorrhage into the germinal layer and ventricles, and also to be very useful for assessing the appearance of the ventricular system. Ultrasound diagnosed extradural haemorrhages but was unhelpful for identifying subarachnoid haemorrhages or lesions in the posterior fossa.

Prediction of death and major handicap in very preterm infants by brain ultrasound.

A linear-array real-time ultrasound scanner was used to examine the brains of all 95 infants born at less than 33 weeks of gestation who were admitted to the neonatal unit of University College Hospital in 1979. Abnormalities were detected in 41 (43%). 36 infants had haemorrhages into the germinal layer (GLH) and/or ventricles (IVH). 8 infants had cerebral atrophy (together with GLH/IVH in 5 infants). 8 (13%) of 63 infants with normal scans or small (grade-I) GLH/IVHs died, whereas 19 (59%) of 32 infants with larger haemorrhages or other intracranial lesions died (p less than 0.0005). At follow-up, at a median corrected age of 45 weeks, only 2 (4%) of 53 infants with normal scans or grade-I haemorrhages had evidence of major neurodevelopmental handicaps, but 5 (38%) of 13 infants with more extensive haemorrhages or cerebral atrophy had major handicaps (p less than 0.005). Brain scanning with ultrasound in the first days of life identified most infants in the population studied who subsequently died or survived with handicaps severe enough to be detected within the first year.

Pneumothorax and cerebral haemorrhage in preterm infants.

Real-time ultrasound was used to examine the brains of all 95 infants born at less than 33 weeks of gestation who were admitted to the neonatal unit of University College Hospital in 1979. Evidence was obtained which strongly suggested that pneumothorax causes and aggravates haemorrhage into the germinal layer and ventricles of preterm infants.

Ultrasound detection of brain damage in preterm infants.

A linear-array real-time ultrasound scanner with a 5 MHz probe was used to examine the brains of 31 infants born at less than 33 weeks of gestation. The equipment was mounted on a small trolley and the infants could easily be scanned in their incubators. 7 of the 31 infants were shown to have cerebral lesions, including haemorrhages into the germinal layer and ventricles, hydrocephalus, and infarction of the periventricular region and cerebral cortex. The type and extent of the lesions were conformed by computerised tomography and at necropsy. Ultrasound scanning is a safe, simple, non-invasive technique that provides valuable information for the diagnosis, investigation, and treatment of lesions in the brains of newborn infants.

Null-cell properties of a lymphoid cell line from a child with acute lymphoblastic leukaemia.

Cultured cells established from the bone marrow of a child with null-cell acute lymphoblastic leukaemia (ALL) have been studied. After 8 months in vitro, the cytological, cytochemical and immunological properties of the cultured cells were very similar to those of the patient's cells. Many of the cultured cells had morphological and cytogenetic abnormalities often found in acute leukaemia. The cells were EBNA-negative. This unique culture of ALL-derived null cells might provide information as to the aetiology and origin of malignant cells.