A locator list of some medieval ophthalmological texts.

At the turn of the last century, there was a flurry of interest in medieval ophthalmological texts. Many of these were edited by practising ophthalmologists, interested in learning and applying the techniques of their distant predecessors. The editions are often difficult to find, and I have listed them along with at least one library location.

The English vernacular afterlife of Benvenutus Grassus, opthalmologist.

This paper traces the history in print of a treatise on ophthalmology by Benvenutus Grassus, De probatissima arte oculorum, originally written in Latin in the late thirteenth century and translated into English in the fifteenth century. It presents evidence of the appearance in print of the English translation as a section of Philip Barrough's The Method of Phisicke in 1583, a book that went through ten subsequent reprintings, the last appearing in 1652. Other evidence is presented on the influence of Benvenutus treatise in ophthalmological works published in the earlier half of the seventeenth century, and both greater and lesser traces are shown to exist. The last appearance of the treatise is in an auctioneer's catalogue of 1713, where apparently the book failed to find a buyer.

Functional auditory development in preterm and full term infants.

Bilateral ABRs were recorded from 452 infants 32-45 weeks conceptional age. Differences in laterality, gender and appropriateness for gestational age were investigated in order to increase our understanding of developmental processes in early life. Rate effects were also studied in a subsample of infants (145 ears). All subjects were free of conditions known to affect ABR parameters. Left/right differences were evident for all ABR measures except the amplitude of wave I. Shorter interwave intervals and larger amplitudes were consistently observed on the right. Females exhibited shorter absolute latencies for waves III and V and larger wave I amplitudes than males. Small for gestational age (SGA) infants displayed shorter wave V latencies and interwave intervals relative to AGA infants. These differences, however, disappeared by term age whereas the contrasts in laterality persisted. Increasing the rate of stimulation reduced wave I amplitude irrespective of conceptional age and increased wave V amplitude prior to term. An increase in wave V latency was more pronounced at the higher rate on the left than the right. There was no interaction between rate and appropriateness for gestational age, although SGA infants had shorter wave V and interwave latencies. Our data indicate a slight but significant right ear advantage in the processing of auditory signals. Gender differences were apparent as well. While research on adults and older children have reported similar findings, no other studies to date have observed these results in neonates. The present work also lends support to the view that accelerated neurological development occurs in growth-retarded infants.

Transient evoked otoacoustic emissions: feasibility in the nursery.

OBJECTIVE: To assess the feasibility of obtaining transient-evoked otoacoustic emissions (TEOAEs) directly in the nursery, to examine the nature of failures in this population, and to determine the time requirements for this test relative to the auditory brain stem response (ABR). DESIGN: TEOAEs and ABRs were recorded from 149 ears, at bedside, in the recovery or intensive care nursery. Subjects were selected according to the risk criteria developed by the Joint Committee on Infant Hearing (1991). Parametric and nonparametric statistical procedures were conducted to describe demographics and test results, to evaluate TEOAE measures by subgroups, and to compare infants by pass/fail outcome. Multivariate techniques were applied to the data to test implicit hypotheses regarding the source of TEOAE failures. In addition, the time required to carry out each test was evaluated in an analysis of variance design. RESULTS: 63.5% of the ears studied passed both procedures, 5% failed both, and 31.5% passed the ABR but failed the TEOAE. Although infants who failed the TEOAE had lower birthweights, shorter gestational periods, and were younger at the time of testing, no statistical differences were found for nursery (intensive care nursery/recovery), bed type (isolette/open crib), ear (left/right), or gender. Infants < 38 wk postconceptional age had smaller TEOAE responses and lower noise levels than did those > 37 wk. There were no differences in environmental noise levels (at the microphone) for passed or failed ears or whether infants were in isolettes or open cribs. Statistically prolonged ABR wave I latencies (Z-scores) at 60 and 30 dB among infants who passed the ABR but failed the TEOAE indicated some obstruction to the acoustic stimulus, whereas TEOAE noise measures neither distinguished these groups nor identified this condition. Three summary times involved in the performance of these tests were obtained: (a) actual test time, measured from start to completion of data collection with a stopwatch; (b) total test time, defined by the actual test time plus the respective preparation, setup, and cleanup (ABR) time; and (c) time reported by the computer system during intrinsic sampling. There were no significant differences in actual or total test times, but these values were distinguished from the machine time, which represented an underestimate of the time required to effectively conduct each test. CONCLUSIONS: These findings show that TEOAEs can be acquired in the nursery, but the high false-positive rate suggests that alternative or additional screening methods, for example, the ABR, must also be available. It must be recognized that TEOAE failures increase test time, thereby negating any savings relative to ABR screening alone.

Risk for ABR abnormalities in the nursery.

The records of 1087 full- and pre-term infants with normal hearing were reviewed for auditory brain-stem response (ABR) abnormalities. Subjects were classified according to various complications common to the newborn. A logistic regression analysis was performed in order to determine the risk of incurring ABR deviations associated with specific diagnoses in the nursery. Infants exposed to cocaine in utero and those with neurological signs or demonstrable brain anomalies were 4-5 times more likely to exhibit deviant ABRs. The synergistic effects of selected predictor variables further increased the risk for abnormal responses depending on gestational age and type of disorder. These results suggest subtle neurologic influences persisting at the time of discharge.

Neonatal status and hearing loss in high-risk infants.

Neurophysiologic and behavioral assessments of auditory function were performed on 224 very low birth weight (less than or equal to 1500 gm) infants requiring intensive care in the nursery. The subjects were studied prospectively from 36 weeks to 4 years of age, as available for follow-up. To classify them according to their neonatal status, we applied a principal components analysis to a number of variables representative of the extent of illness and of patient care in early postnatal life. The subjects were then divided into neonatal status quartiles and evaluated for hearing outcome. All those with sensorineural hearing loss fell exclusively into the lowest neonatal status quartile. Sensorineural hearing loss was statistically associated (1) with greater amounts of furosemide administration for longer durations and in combination with aminoglycoside antibiotics and (2) with more episodes of low pH, hypoxemia, or both, higher total bilirubin levels, and substantially lower neonatal status scores. Birth weight, gestational age, highest creatinine level, Apgar score, and aminoglycosides alone were not systematically related to hearing capacity. Subjects in the lowest neonatal status quartile also had a considerably higher incidence of middle ear disorders, characterized by elevated thresholds and prolonged auditory brain stem-response latencies reflective of conductive hearing loss. We conclude that protracted illness and its associated treatment, independently of specific diagnostic categories, constitute important risk factors for permanent hearing loss and for transient hearing loss in early life.

Neonatal status: an objective scoring method for identifying infants at risk for poor outcome.

The likelihood of sustaining neurological, sensory or cognitive deficits is considerably greater for very low birthweight (VLBW) infants who require intensive care in early postnatal life than those without major neonatal illness. Identifying which, if any, medical events are responsible for an adverse outcome is most difficult in the face of multiple concurrent complications. In this research, a principal components analysis was performed in order to arrive at a set of orthogonal variables which succinctly described clinical involvement in the nursery. With this procedure, a single hypothetical factor depicting neonatal status (NS) was computed. Principal component scores were then generated for NS and assigned to 252 VLBW (less than 1500 g) infants. These subjects were followed prospectively from birth to 4 years of age. Standardized measures of neurological, sensory and intellectual function were regularly administered. Neonatal status was shown to be significantly correlated with the various test results and predictive of long-term development. When subjects were divided into quartiles with respect to NS, a specific subgroup was identified as "at high risk" for poor outcome. Those subjects falling into the lower quartile incurred more neurological abnormalities persisting beyond the first year. They also suffered a higher incidence of intracranial hemorrhage and sensori-neural hearing loss. In addition, the lower 25%, as a group, scored well below all others on traditional tests of mental ability. These differences were sustained throughout infancy and early childhood and could not be attributed to a number of demographic variables including sex, gestational age, birthweight, Apgar scores or parental educational level.

Neurobehavioral and neurophysiological assessment of healthy and "at-risk" full-term infants.

The Neurological and Adaptive Capacity Score (NACS) and the auditory brainstem response (ABR) are measures that, respectively, provide neurobehavioral and neurophysiological information regarding the status of the central nervous system (CNS) in the neonatal period. We evaluated these measures as indices of CNS functioning in 15 neonates born at risk for neurological sequelae and 15 healthy controls. Significant group differences were observed on the NACS. The ABR failed to distinguish the groups, but abnormal responses were obtained from 1 severely asphyxiated infant. Measures used to define ABR abnormality were also correlated among risk infants. We concluded that the NACS is sensitive to mild but diffuse disturbances, whereas the ABR appears to reflect insults to the brainstem structures that are susceptible to damage from anoxia. Utilization of both tests provides more complete information regarding CNS integrity in neonates.

Maturation of contralateral brain-stem responses in preterm infants.

Average auditory brain-stem responses (ABRs) evoked by left and right ear stimulation of varying intensities were recorded from ipsilateral and contralateral scalp placements in human neonates. Subjects included pre-term infants, healthy full-term infants and high risk, full-term infants. Pre-term infants were classified into 4 age groups ranging from 29 to 41 weeks post-conceptional age (PCA). Significant ipsilateral/contralateral differences were observed. Further, this effect was highly dependent upon age. The youngest pre-term infants were devoid of contralateral activity despite robust ipsilateral responses. The emergence and evolution of the contralateral wave form could readily be visualized from 31 to 37 weeks PCA. The contralateral response was uninfluenced by stimulus intensity but appeared to be related to the amplitude of the ipsilateral response. No systematic ear differences were noted. Pre-term infants tested between 38 and 41 weeks PCA (term equivalence) showed some persisting immaturity in terms of the ABR. Healthy and sick full-term infants were indistinguishable with respect to ipsilateral or contralateral potentials. On the other hand, very ill 6-week-old infants showed specific contralateral abnormalities.