We assessed the potential clinical usefulness of pattern-reversal visual-evoked potentials in the... more We assessed the potential clinical usefulness of pattern-reversal visual-evoked potentials in the diagnosis of amblyopia. Twenty-seven children with anisometropic amblyopia and four children without amblyopia participated. Estimates of visual acuity for each eye (Snellen visual acuity) were obtained by conventional psychometric methods. Visual-evoked potentials to reversing checks subtending 15 minutes of visual arc were also obtained. Visual-evoked potential testing and interpretation were done in a masked fashion. Ten of the 31 children were retested seven to 21 days after the first test to estimate reliability of the procedures. Of the 27 amblyopic children, 22 were correctly identified by the visual-evoked potential test alone. In four patients initial visual-evoked potential tests failed to identify the disparity in visual acuity between the eyes and retests in two of the four again had false-negative results. In one child initial visual-evoked potential testing incorrectly identified the amblyopic eye but repeat testing did identify it. Of the four children with symmetrically good vision, three were correctly identified as normal by the initial visual-evoked potential test. The other normal child was incorrectly identified by the visual-evoked potential test as having amblyopia.
This study evaluated the contribution of brainstem auditory evoked potentials (BAEPs) and median ... more This study evaluated the contribution of brainstem auditory evoked potentials (BAEPs) and median nerve somatosensory evoked potentials (SEPs) to the assessment of brainstem dysfunction in infants with myelomeningocele and Arnold-Chiari malformation. 16 infants under one year of age were studied. Six had infant brainstem syndrome (IBS). 11 had abnormally prolonged I-V interwave latency (brainstem transmission time, BSTT); BSTT did not differentiate those patients with and without IBS. The cortical 'N20' component of the median-nerve SEPs was absent or had low amplitude and prolonged latency in all six patients with clinical signs of brainstem dysfunction and in four without. Median-nerve SEPs were normal in the patients without IBS. There was a significant difference between patients with and without IBS. Median-nerve SEPs may be a helpful measure of brainstem function in infants with Arnold-Chiari malformation.
Proceedings the Annual Symposium on Computer Application Sic in Medical Care Symposium on Computer Applications in Medical Care, Oct 17, 1979
Developments in computer technology and the results of more than a decade of research have result... more Developments in computer technology and the results of more than a decade of research have resulted in clinically important advances in the understanding of the relationships between the electrical potentials which can be recorded from the surface of the head (EPs) and sensory information processing by the CNS. Clinically validated applications of EPs include audiometry and assessment of visual and somatosensory abnormalities. Auditory brainstem EPs, besides being useful in evaluation of peripheral auditory function are being applied with some success to the understanding of diseases involving the brainstem. Research on the relationships between EPs and learning, language, and psychiatric disorders holds promise for the development of new diagnostic tools.
A prospective study of 1,144 infants and their families was performed. Smoking and family histori... more A prospective study of 1,144 infants and their families was performed. Smoking and family histories were evaluated with respect to the incidence of lower respiratory disease during the first year of life. It was found that (1) tracheitis and bronchitis occurred significantly more frequently in infants exposed to cigarette smoke in the home, (2) maternal smoking imposed greater risks upon the infant than paternal smoking, (3) occurrence of neither tracheitis nor bronchitis showed a consistent relationship to the number of cigarettes smoked, (4) a family history that was positive for respiratory illness (chronic cough or bronchitis) significantly influenced the incidence of bronchitis, (5) too few cases of laryngitis and pneumonia were seen to warrant any opinions regarding the adverse influence of either smoking or a family history that was positive for respiratory illness, and (6) occurrence of bronchiolitis was not affected by the presence of a smoker nor influenced by a family history that was positive for respiratory illness. It is concluded that passive smoking is dangerous to the health of infants and that infants born to families with a history that is positive for respiratory illness (chronic cough or bronchitis) are at risk of developing bronchitis.
We assessed the potential clinical usefulness of pattern-reversal visual-evoked potentials in the... more We assessed the potential clinical usefulness of pattern-reversal visual-evoked potentials in the diagnosis of amblyopia. Twenty-seven children with anisometropic amblyopia and four children without amblyopia participated. Estimates of visual acuity for each eye (Snellen visual acuity) were obtained by conventional psychometric methods. Visual-evoked potentials to reversing checks subtending 15 minutes of visual arc were also obtained. Visual-evoked potential testing and interpretation were done in a masked fashion. Ten of the 31 children were retested seven to 21 days after the first test to estimate reliability of the procedures. Of the 27 amblyopic children, 22 were correctly identified by the visual-evoked potential test alone. In four patients initial visual-evoked potential tests failed to identify the disparity in visual acuity between the eyes and retests in two of the four again had false-negative results. In one child initial visual-evoked potential testing incorrectly identified the amblyopic eye but repeat testing did identify it. Of the four children with symmetrically good vision, three were correctly identified as normal by the initial visual-evoked potential test. The other normal child was incorrectly identified by the visual-evoked potential test as having amblyopia.
We developed an automated visual acuity testing program that uses an E optotype with surrounding ... more We developed an automated visual acuity testing program that uses an E optotype with surrounding confusion bars. The computer software program runs on Apple II equipment and a black-and-white monitor with a five-inch screen. The program is available in response box and joystick versions. The test is suitable for children older than 31/2 to 4 years of age and for adults. A t-test on the same floppy disk as the visual acuity programs is used to test the probability that the differences in test results are greater than chance. Visual acuities of 20 normal subjects were reduced by means of plus lenses. Test-retest acuity correlation coefficients were similar for letter charts and computer-generated E optotypes, suggesting approximately equal reliability under the test conditions employed. Visual acuities of 12 amblyopic eyes were obtained by a Ferris-type letter chart and computer-generated E optotypes. The correlation coefficient was +0.93, suggesting similar test results by these two methods.
Electroencephalography and Clinical Neurophysiology, 1995
Society Proceedings optokinetic nystagmus. This ML-VsEP component and the presaccadic spike proba... more Society Proceedings optokinetic nystagmus. This ML-VsEP component and the presaccadic spike probably represent highly synchronous activity of the motor units of the extra-ocular muscles which precedes and initiates the actual eye movements. The similarity between this ML-VsEP component and the presaccadic spike indicates that the eye movements which follow the angular acceleration stimuli used to elicit the ML-VsEP probably begin with a saccade. A comparison of the forehead-mastoid and the electro-oculogram recordings during voluntary eye movements showed that the eye movements induced by the head accelerations used to elicit the ML-VsEP were anti-compensatory in direction; that is they were not typical of the vestibulo-ocular reflex during which the eyes are moved in a direction opposite to that of head movement in order to maintain a stable image on the retina. Further experimentation is required to substantiate these initial observations.
Adult golden hamsters restricted to 1 g of food per day developed polydipsia and polyuria. Unlike... more Adult golden hamsters restricted to 1 g of food per day developed polydipsia and polyuria. Unlike the rabbit, the hamster did not show cessation of polydipsia when given additional NaCl and did not show how high urinary loss of Na+. From three to 10 days were required for the development of a vigorous polydipsia on this schedule.
Electroencephalography and Clinical Neurophysiology, 1978
Serial recordings of auditory evoked potentials (AEPs) to clicks were obtained using a vertex-mas... more Serial recordings of auditory evoked potentials (AEPs) to clicks were obtained using a vertex-mastoid derivation from 16 normal children during sleep over an age span from near birth to age 3. The AEP components studied were: N0 (38 +/- 10 msec), P1 (79 +/- 24 msec), N1 (109 +/- 39 msec), P2 (186 +/- 35 msec), N2 (409 +/- 97 msec), P3A (554 +/- 116 msec), P3B (757 +/- 121 msec) and P3 (728 +/- 128 msec). Amplitudes and latencies of the components were calculated and regressions of the measures on age were computed for the group as a whole, for each subject and for subsets of the data based on sleep stage, sex, order of stimulus presentation and a rearing/race factor. For the group as a whole the latencies of P1, P2, P3, and P3B decreased with age. The amplitudes of P1N1 and the N2P3 waves increased with age. Most change occurred during the first year of life. In general, the changes with age were also found to hold across all of the factors examined, although individuals varied widely in the degree to which they conformed to the trends found for the data as a whole. The amount contributed by each of the factors mentioned above to the total variance was estimated. The proportions varied for different EP components but, in general, age, sleep state, and subject factors other than rearing/race and sex accounted for most variance. One half to 5/6 of the unexplained variance in AEP latencies and amplitudes (i.e., that not due to age, sleep state, etc.) occurred across rather than within subjects. For both the group as a whole and for individual children, P2 and N2 latencies were found to exhibit the greatest stability across time. The results of the longitudinal study reported here were in good agreement with those of a previous study from this laboratory which utilized a cross-sectional design.
Computer-averaged auditory evoked potentials were found to be abnormal in infants hospitalized be... more Computer-averaged auditory evoked potentials were found to be abnormal in infants hospitalized because of severe malnutrition (marasmus). They improved as the infants' somatic growth improved during the course of treatment, but were still deviant at the time of discharge from the hospital and at subsequent outpatient follow-up. Abnormalities in evoked potentials may reflect a long-lasting effect of malnutrition on brain function.
ABSTRACT Six children with cortical blindness following head trauma or meningitis had visual evok... more ABSTRACT Six children with cortical blindness following head trauma or meningitis had visual evoked response studies initially performed shortly after the onset of blindness. On long-term follow-up examination, three had evidence of visual deficit and five exhibited varying degrees of psychomotor retardation. Initial and follow-up visual evoked responses were analyzed and correlated with changes in visual and clinical status. The analyses suggest that change in short latency visual evoked response components correlates with visual ability whereas change in longer latency visual evoked response components correlates with level of psychomotor function.
Fifteen infants with moderate to severe congenital renal disease were prospectively studied by se... more Fifteen infants with moderate to severe congenital renal disease were prospectively studied by serial renal, neurodevelopmental, neurophysiologic, and anthropometric assessments. The observation period ranged from 3 to 25 months (mean = 40.9). Eight patients maintained a Mental Development Index (MDI) above the 46th percentile (>-4 SD) and comprised group 4. Of the remaining seven patients (group 2), three had an MDI <46th percentile when first studied and four had serial decreases of the MDI to <46th percentile. Although motor development was more delayed in group 2 at study entry, there were no significant changes of motor performance levels for either group during the study period. Group 2 patients had smaller length (p <0.05) and head circumference (p <0.05) standard deviation scores in comparison with group 4, and they had higher serum creatinine values (mean = 3.8 vs 4.3 mg/dl, respectively; p <0.04). By spectral electroencephalography, the expected progressive increase of the frequency of cerebral cortical background activity with age was demonstrated in group 4 but was not seen in group 2 (multivariate analysis of variance p <0.03). This increase of faster-frequency activity was primarily manifested in the left cerebral hemisphere of group 4 patients (p <0.04), a finding that was also absent in group 2. The frequent occurrence of neurodevelopmental abnormalities in infants with renal failure is possibly a consequence of impaired dominant hemispheric maturation in the first several years of life, which is clinically manifested as deterioration of cognitive function. (J PEDIATR 4989;444:234-8) Chronic renal failure in infancy is ~associated with profound adverse effects on growth and neurodevelopmental maturation.l, 2 Studies of the nutritional and growth distur
✓ Significant problems regarding the measurement technique currently used to choose nerve roots f... more ✓ Significant problems regarding the measurement technique currently used to choose nerve roots for sectioning in the selective dorsal rhizotomy procedure have recently been reported. To better understand the source of these problems, a series of six experiments was performed in which the selective rhizotomy technique was applied to cats that were either intact, decerebrate, or spinalized. Measurements were made before and after partial rhizotomy. In decerebrate preparations, large, spontaneous changes in reflex threshold were observed over short periods of time, especially after partial rhizotomy was performed, and threshold changes greater than 1000% could be observed over 10-minute periods. Using constant-current stimulation of the dorsal root at threshold, the response of each ipsilateral leg muscle demonstrated frequent changes, and changes coincided with the variability in threshold estimation. In addition, very low thresholds were measured (0.1 to 0.25 mA) in half (3 of 6) of...
The purpose of this study was to discover whether sensorineural hearing loss was a significant co... more The purpose of this study was to discover whether sensorineural hearing loss was a significant complication in survivors of persistent fetal circulation. Eleven patients were followed to 36 months. Hearing assessments were performed on at least two occasions using brain stem auditory evoked response testing and behavioral audiometry. Three of 11 babies had bilateral, progressive sensorineural hearing loss. No clear relationship could be found between hearing loss and any of the clinical variables examined in this study.
This study evaluated the contribution of brainstem auditory evoked potentials (BAEPs) and median ... more This study evaluated the contribution of brainstem auditory evoked potentials (BAEPs) and median nerve somatosensory evoked potentials (SEPs) to the assessment of brainstem dysfunction in infants with myelomeningocele and Arnold-Chiari malformation. 16 infants under one year of age were studied. Six had infant brainstem syndrome (IBS). 11 had abnormally prolonged I-V interwave latency (brainstem transmission time, BSTT); BSTT did not differentiate those patients with and without IBS. The cortical &#39;N20&#39; component of the median-nerve SEPs was absent or had low amplitude and prolonged latency in all six patients with clinical signs of brainstem dysfunction and in four without. Median-nerve SEPs were normal in the patients without IBS. There was a significant difference between patients with and without IBS. Median-nerve SEPs may be a helpful measure of brainstem function in infants with Arnold-Chiari malformation.
Brainstem auditory evoked potentials (BAEPs) were examined prospectively in ten clinically brain-... more Brainstem auditory evoked potentials (BAEPs) were examined prospectively in ten clinically brain-dead and 13 comatose nonbrain-dead children. All clinically brain-dead children failed to demonstrate brainstem impulse transmission, displaying no waves or only wave I. The comatose, nonbrain-dead children maintained evidence of brainstem electrical activity, manifested by at least two waveforms. This suggests that BAEPs are a useful noninvasive method of supporting the clinical diagnosis of brain death in children.
✓ The variability of reflex responses during selective dorsal rhizotomy was studied in eight chil... more ✓ The variability of reflex responses during selective dorsal rhizotomy was studied in eight children between the ages of 3 and 7 years. For a given dorsal root or rootiet, the electrical reflex threshold and response varied considerably when observed over several minutes. Changes in electrode pressure, mechanical dissection of the root, and reflex spatial facilitation were all found to contribute to the variability. Even when electrode pressure was held constant, intrinsic spinal cord reflex variability substantially weakened the predictability of the intraoperative selection method used during this surgery.
We assessed the potential clinical usefulness of pattern-reversal visual-evoked potentials in the... more We assessed the potential clinical usefulness of pattern-reversal visual-evoked potentials in the diagnosis of amblyopia. Twenty-seven children with anisometropic amblyopia and four children without amblyopia participated. Estimates of visual acuity for each eye (Snellen visual acuity) were obtained by conventional psychometric methods. Visual-evoked potentials to reversing checks subtending 15 minutes of visual arc were also obtained. Visual-evoked potential testing and interpretation were done in a masked fashion. Ten of the 31 children were retested seven to 21 days after the first test to estimate reliability of the procedures. Of the 27 amblyopic children, 22 were correctly identified by the visual-evoked potential test alone. In four patients initial visual-evoked potential tests failed to identify the disparity in visual acuity between the eyes and retests in two of the four again had false-negative results. In one child initial visual-evoked potential testing incorrectly identified the amblyopic eye but repeat testing did identify it. Of the four children with symmetrically good vision, three were correctly identified as normal by the initial visual-evoked potential test. The other normal child was incorrectly identified by the visual-evoked potential test as having amblyopia.
This study evaluated the contribution of brainstem auditory evoked potentials (BAEPs) and median ... more This study evaluated the contribution of brainstem auditory evoked potentials (BAEPs) and median nerve somatosensory evoked potentials (SEPs) to the assessment of brainstem dysfunction in infants with myelomeningocele and Arnold-Chiari malformation. 16 infants under one year of age were studied. Six had infant brainstem syndrome (IBS). 11 had abnormally prolonged I-V interwave latency (brainstem transmission time, BSTT); BSTT did not differentiate those patients with and without IBS. The cortical &#39;N20&#39; component of the median-nerve SEPs was absent or had low amplitude and prolonged latency in all six patients with clinical signs of brainstem dysfunction and in four without. Median-nerve SEPs were normal in the patients without IBS. There was a significant difference between patients with and without IBS. Median-nerve SEPs may be a helpful measure of brainstem function in infants with Arnold-Chiari malformation.
Proceedings the Annual Symposium on Computer Application Sic in Medical Care Symposium on Computer Applications in Medical Care, Oct 17, 1979
Developments in computer technology and the results of more than a decade of research have result... more Developments in computer technology and the results of more than a decade of research have resulted in clinically important advances in the understanding of the relationships between the electrical potentials which can be recorded from the surface of the head (EPs) and sensory information processing by the CNS. Clinically validated applications of EPs include audiometry and assessment of visual and somatosensory abnormalities. Auditory brainstem EPs, besides being useful in evaluation of peripheral auditory function are being applied with some success to the understanding of diseases involving the brainstem. Research on the relationships between EPs and learning, language, and psychiatric disorders holds promise for the development of new diagnostic tools.
A prospective study of 1,144 infants and their families was performed. Smoking and family histori... more A prospective study of 1,144 infants and their families was performed. Smoking and family histories were evaluated with respect to the incidence of lower respiratory disease during the first year of life. It was found that (1) tracheitis and bronchitis occurred significantly more frequently in infants exposed to cigarette smoke in the home, (2) maternal smoking imposed greater risks upon the infant than paternal smoking, (3) occurrence of neither tracheitis nor bronchitis showed a consistent relationship to the number of cigarettes smoked, (4) a family history that was positive for respiratory illness (chronic cough or bronchitis) significantly influenced the incidence of bronchitis, (5) too few cases of laryngitis and pneumonia were seen to warrant any opinions regarding the adverse influence of either smoking or a family history that was positive for respiratory illness, and (6) occurrence of bronchiolitis was not affected by the presence of a smoker nor influenced by a family history that was positive for respiratory illness. It is concluded that passive smoking is dangerous to the health of infants and that infants born to families with a history that is positive for respiratory illness (chronic cough or bronchitis) are at risk of developing bronchitis.
We assessed the potential clinical usefulness of pattern-reversal visual-evoked potentials in the... more We assessed the potential clinical usefulness of pattern-reversal visual-evoked potentials in the diagnosis of amblyopia. Twenty-seven children with anisometropic amblyopia and four children without amblyopia participated. Estimates of visual acuity for each eye (Snellen visual acuity) were obtained by conventional psychometric methods. Visual-evoked potentials to reversing checks subtending 15 minutes of visual arc were also obtained. Visual-evoked potential testing and interpretation were done in a masked fashion. Ten of the 31 children were retested seven to 21 days after the first test to estimate reliability of the procedures. Of the 27 amblyopic children, 22 were correctly identified by the visual-evoked potential test alone. In four patients initial visual-evoked potential tests failed to identify the disparity in visual acuity between the eyes and retests in two of the four again had false-negative results. In one child initial visual-evoked potential testing incorrectly identified the amblyopic eye but repeat testing did identify it. Of the four children with symmetrically good vision, three were correctly identified as normal by the initial visual-evoked potential test. The other normal child was incorrectly identified by the visual-evoked potential test as having amblyopia.
We developed an automated visual acuity testing program that uses an E optotype with surrounding ... more We developed an automated visual acuity testing program that uses an E optotype with surrounding confusion bars. The computer software program runs on Apple II equipment and a black-and-white monitor with a five-inch screen. The program is available in response box and joystick versions. The test is suitable for children older than 31/2 to 4 years of age and for adults. A t-test on the same floppy disk as the visual acuity programs is used to test the probability that the differences in test results are greater than chance. Visual acuities of 20 normal subjects were reduced by means of plus lenses. Test-retest acuity correlation coefficients were similar for letter charts and computer-generated E optotypes, suggesting approximately equal reliability under the test conditions employed. Visual acuities of 12 amblyopic eyes were obtained by a Ferris-type letter chart and computer-generated E optotypes. The correlation coefficient was +0.93, suggesting similar test results by these two methods.
Electroencephalography and Clinical Neurophysiology, 1995
Society Proceedings optokinetic nystagmus. This ML-VsEP component and the presaccadic spike proba... more Society Proceedings optokinetic nystagmus. This ML-VsEP component and the presaccadic spike probably represent highly synchronous activity of the motor units of the extra-ocular muscles which precedes and initiates the actual eye movements. The similarity between this ML-VsEP component and the presaccadic spike indicates that the eye movements which follow the angular acceleration stimuli used to elicit the ML-VsEP probably begin with a saccade. A comparison of the forehead-mastoid and the electro-oculogram recordings during voluntary eye movements showed that the eye movements induced by the head accelerations used to elicit the ML-VsEP were anti-compensatory in direction; that is they were not typical of the vestibulo-ocular reflex during which the eyes are moved in a direction opposite to that of head movement in order to maintain a stable image on the retina. Further experimentation is required to substantiate these initial observations.
Adult golden hamsters restricted to 1 g of food per day developed polydipsia and polyuria. Unlike... more Adult golden hamsters restricted to 1 g of food per day developed polydipsia and polyuria. Unlike the rabbit, the hamster did not show cessation of polydipsia when given additional NaCl and did not show how high urinary loss of Na+. From three to 10 days were required for the development of a vigorous polydipsia on this schedule.
Electroencephalography and Clinical Neurophysiology, 1978
Serial recordings of auditory evoked potentials (AEPs) to clicks were obtained using a vertex-mas... more Serial recordings of auditory evoked potentials (AEPs) to clicks were obtained using a vertex-mastoid derivation from 16 normal children during sleep over an age span from near birth to age 3. The AEP components studied were: N0 (38 +/- 10 msec), P1 (79 +/- 24 msec), N1 (109 +/- 39 msec), P2 (186 +/- 35 msec), N2 (409 +/- 97 msec), P3A (554 +/- 116 msec), P3B (757 +/- 121 msec) and P3 (728 +/- 128 msec). Amplitudes and latencies of the components were calculated and regressions of the measures on age were computed for the group as a whole, for each subject and for subsets of the data based on sleep stage, sex, order of stimulus presentation and a rearing/race factor. For the group as a whole the latencies of P1, P2, P3, and P3B decreased with age. The amplitudes of P1N1 and the N2P3 waves increased with age. Most change occurred during the first year of life. In general, the changes with age were also found to hold across all of the factors examined, although individuals varied widely in the degree to which they conformed to the trends found for the data as a whole. The amount contributed by each of the factors mentioned above to the total variance was estimated. The proportions varied for different EP components but, in general, age, sleep state, and subject factors other than rearing/race and sex accounted for most variance. One half to 5/6 of the unexplained variance in AEP latencies and amplitudes (i.e., that not due to age, sleep state, etc.) occurred across rather than within subjects. For both the group as a whole and for individual children, P2 and N2 latencies were found to exhibit the greatest stability across time. The results of the longitudinal study reported here were in good agreement with those of a previous study from this laboratory which utilized a cross-sectional design.
Computer-averaged auditory evoked potentials were found to be abnormal in infants hospitalized be... more Computer-averaged auditory evoked potentials were found to be abnormal in infants hospitalized because of severe malnutrition (marasmus). They improved as the infants&#39; somatic growth improved during the course of treatment, but were still deviant at the time of discharge from the hospital and at subsequent outpatient follow-up. Abnormalities in evoked potentials may reflect a long-lasting effect of malnutrition on brain function.
ABSTRACT Six children with cortical blindness following head trauma or meningitis had visual evok... more ABSTRACT Six children with cortical blindness following head trauma or meningitis had visual evoked response studies initially performed shortly after the onset of blindness. On long-term follow-up examination, three had evidence of visual deficit and five exhibited varying degrees of psychomotor retardation. Initial and follow-up visual evoked responses were analyzed and correlated with changes in visual and clinical status. The analyses suggest that change in short latency visual evoked response components correlates with visual ability whereas change in longer latency visual evoked response components correlates with level of psychomotor function.
Fifteen infants with moderate to severe congenital renal disease were prospectively studied by se... more Fifteen infants with moderate to severe congenital renal disease were prospectively studied by serial renal, neurodevelopmental, neurophysiologic, and anthropometric assessments. The observation period ranged from 3 to 25 months (mean = 40.9). Eight patients maintained a Mental Development Index (MDI) above the 46th percentile (>-4 SD) and comprised group 4. Of the remaining seven patients (group 2), three had an MDI <46th percentile when first studied and four had serial decreases of the MDI to <46th percentile. Although motor development was more delayed in group 2 at study entry, there were no significant changes of motor performance levels for either group during the study period. Group 2 patients had smaller length (p <0.05) and head circumference (p <0.05) standard deviation scores in comparison with group 4, and they had higher serum creatinine values (mean = 3.8 vs 4.3 mg/dl, respectively; p <0.04). By spectral electroencephalography, the expected progressive increase of the frequency of cerebral cortical background activity with age was demonstrated in group 4 but was not seen in group 2 (multivariate analysis of variance p <0.03). This increase of faster-frequency activity was primarily manifested in the left cerebral hemisphere of group 4 patients (p <0.04), a finding that was also absent in group 2. The frequent occurrence of neurodevelopmental abnormalities in infants with renal failure is possibly a consequence of impaired dominant hemispheric maturation in the first several years of life, which is clinically manifested as deterioration of cognitive function. (J PEDIATR 4989;444:234-8) Chronic renal failure in infancy is ~associated with profound adverse effects on growth and neurodevelopmental maturation.l, 2 Studies of the nutritional and growth distur
✓ Significant problems regarding the measurement technique currently used to choose nerve roots f... more ✓ Significant problems regarding the measurement technique currently used to choose nerve roots for sectioning in the selective dorsal rhizotomy procedure have recently been reported. To better understand the source of these problems, a series of six experiments was performed in which the selective rhizotomy technique was applied to cats that were either intact, decerebrate, or spinalized. Measurements were made before and after partial rhizotomy. In decerebrate preparations, large, spontaneous changes in reflex threshold were observed over short periods of time, especially after partial rhizotomy was performed, and threshold changes greater than 1000% could be observed over 10-minute periods. Using constant-current stimulation of the dorsal root at threshold, the response of each ipsilateral leg muscle demonstrated frequent changes, and changes coincided with the variability in threshold estimation. In addition, very low thresholds were measured (0.1 to 0.25 mA) in half (3 of 6) of...
The purpose of this study was to discover whether sensorineural hearing loss was a significant co... more The purpose of this study was to discover whether sensorineural hearing loss was a significant complication in survivors of persistent fetal circulation. Eleven patients were followed to 36 months. Hearing assessments were performed on at least two occasions using brain stem auditory evoked response testing and behavioral audiometry. Three of 11 babies had bilateral, progressive sensorineural hearing loss. No clear relationship could be found between hearing loss and any of the clinical variables examined in this study.
This study evaluated the contribution of brainstem auditory evoked potentials (BAEPs) and median ... more This study evaluated the contribution of brainstem auditory evoked potentials (BAEPs) and median nerve somatosensory evoked potentials (SEPs) to the assessment of brainstem dysfunction in infants with myelomeningocele and Arnold-Chiari malformation. 16 infants under one year of age were studied. Six had infant brainstem syndrome (IBS). 11 had abnormally prolonged I-V interwave latency (brainstem transmission time, BSTT); BSTT did not differentiate those patients with and without IBS. The cortical &#39;N20&#39; component of the median-nerve SEPs was absent or had low amplitude and prolonged latency in all six patients with clinical signs of brainstem dysfunction and in four without. Median-nerve SEPs were normal in the patients without IBS. There was a significant difference between patients with and without IBS. Median-nerve SEPs may be a helpful measure of brainstem function in infants with Arnold-Chiari malformation.
Brainstem auditory evoked potentials (BAEPs) were examined prospectively in ten clinically brain-... more Brainstem auditory evoked potentials (BAEPs) were examined prospectively in ten clinically brain-dead and 13 comatose nonbrain-dead children. All clinically brain-dead children failed to demonstrate brainstem impulse transmission, displaying no waves or only wave I. The comatose, nonbrain-dead children maintained evidence of brainstem electrical activity, manifested by at least two waveforms. This suggests that BAEPs are a useful noninvasive method of supporting the clinical diagnosis of brain death in children.
✓ The variability of reflex responses during selective dorsal rhizotomy was studied in eight chil... more ✓ The variability of reflex responses during selective dorsal rhizotomy was studied in eight children between the ages of 3 and 7 years. For a given dorsal root or rootiet, the electrical reflex threshold and response varied considerably when observed over several minutes. Changes in electrode pressure, mechanical dissection of the root, and reflex spatial facilitation were all found to contribute to the variability. Even when electrode pressure was held constant, intrinsic spinal cord reflex variability substantially weakened the predictability of the intraoperative selection method used during this surgery.
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Papers by Ira Weiss