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Biomedical subjects

J Mushin

Publications and source records attributed to J Mushin.

14 recordsLinked to original sources
PubMed1986

Visual function in the newborn infant: is it cortically mediated?

Reasonably normal visual behaviour was observed in premature infants in the neonatal period up to about 48 weeks' postmenstrual age even when there was gross destruction of the cortex in the occipital region. Symmetrical visual evoked responses could be elicited at this time even when asymmetrical lesions of the occipital cortex had been demonstrated on ultrasound scan; the visual evoked response became asymmetrical later, around the age of 2 months. A visual evoked response, albeit of abnormal waveform, was recorded in an infant with complete absence of the visual cortex. These findings suggest that early visual function, both behavioural and electrophysiological, is not dependent on the cortex but appears to be mediated through subcortical pathways.

Abnormalities, Multiple↗
PubMed1986

The visual evoked potential in neonates with occipital lesions and holoprosencephaly.

Visual evoked potentials (VEPs) were studied in 4 preterm and 2 fullterm infants in whom unilateral lesions of the occipital cortex were demonstrable on cranial ultrasonography. In the neonatal period, symmetrical responses were recorded from the two hemispheres, and the VEPs only became asymmetrical at the age of 2-3 months. Evoked responses to flash stimulation were also recorded initially in an infant with complete holoprosencephaly. These findings, together with previous reports on the maturation of the VEPs in the neonatal period, suggest that the early evoked response may be subcortical rather than cortical in origin.

Brain↗
PubMed1985

Maturation of the visual evoked response and its correlation with visual acuity in preterm infants.

Visual evoked responses (VERs) were elicited in 70 infants with postmenstrual ages between 30 and 39 weeks. On the basis of neurological and ultrasound examinations, 30 of the infants were classed as neurologically normal and 40 as abnormal: 26 of the latter had periventricular haemorrhage. Initially the VER consisted of a negative deflection only, and the appearance of a positive wave immediately preceding the negative deflection was taken to indicate maturation of the VER. Maturation was significantly delayed in the neurologically abnormal infants, and the delay was related to the degree of neurological insult. The visual acuity of 32 infants was estimated within seven days of the VER recording. There was a correlation of 79 per cent between the VER and the data for visual acuity.

Birth Weight↗
PubMed1985

Developmental sequence of periventricular leukomalacia. Correlation of ultrasound, clinical, and nuclear magnetic resonance functions.

The evolution of severe periventricular leukomalacia was followed by ultrasonography in three newborn infants, and the subsequent myelination of the brain was assessed by nuclear magnetic resonance imaging. Four stages of periventricular leukomalacia could be identified by ultrasonography; (1) initial congestion, followed by (2) relative normalisation, (3) development of cysts, and (4) resolution of cysts but development of ventricular enlargement. All infants exhibited abnormal neurological signs from 36 weeks conceptual age and had unequivocal signs of cerebral palsy by 6 to 9 months of age. One infant became cortically blind but the other two seemed to have normal vision. Nuclear magnetic resonance imaging showed some abnormality of the ventricular system and delayed myelination in all three infants. The delay was most noticeable in the opticothalamic region, which was also the site of the most extensive lesions observed on ultrasonography. Progress in myelination was observed in the infants where a repeat scan was performed.

Brain Diseases↗
PubMed1984

Visual evoked responses to light emitting diode (LED) photostimulation in newborn infants.

The use of a Xenon discharge stroboscope to elicit VERs in a neonatal intensive care unit has several disadvantages. To overcome these a photostimulator has been developed which consists of an array of 25 red light emitting diodes (LEDs). The LEDs are driven by pulses of fixed length and current and the output intensity is controlled by the pulse repetition rate. Such a photostimulator is compact and can be hand-held inside a cot or incubator. Using this method VERs have been recorded in healthy full-term and pre-term infants which are comparable in wave form and latency to those elicited by a stroboscope.

Electroencephalography↗
PubMed1983

The maturation of visual acuity in neurologically normal and abnormal newborn infants.

The maturation of visual acuity was studied in 162 neurologically normal and 96 neurologically abnormal newborn infants. Ninety-five percent of the neurologically normal infants developed an acuity of 80 min arc by 35 weeks postmenstrual age (PMA) but only 50% developed an acuity of 40 min arc by 40 weeks PMA. Neurologically abnormal infants, and in particular those with periventricular haemorrhage (PVH), had a delay in the development of acuity. There was a close correlation between the development of 80 min arc acuity and the appearance of the first positivity of the flash visually evoked potential (VEP).

Cerebral Hemorrhage↗
PubMed1976

The pattern-evoked potential in compression of the anterior visual pathways.

Pattern evoked responses have been recorded in 19 patients with compression of the optic nerve, chiasm or tract, verified at operation. These included 4 patients with orbital tumours, 5 with intracranial meningiomas, 2 with craniopharyngiomas and 8 with pituitary tumours. The evoked response was abnormal in all except one of these patients. The pattern of abnormalities in the response, however, differed from that in the earlier series of patients with primary demyelinating disease. The incidence of delayed responses was much lower, and the magnitude of the delays was smaller. Absent responses were particularly characteristic of patients with intracranial meningiomas. Tumours arising in the region of the sella turcica were associated with a high incidence of abnormalities of the waveform of the response, and asymmetry of the field of the occipital evoked potential was especially characteristic of this group. Most, but not all, asymmetric cases were associated with field defects.

Adult↗
PubMed1973

Visual evoked response in diagnosis of multiple sclerosis.

The diagnostic value of the pattern-evoked response has been assessed in 73 patients referred because of suspected multiple sclerosis. Altogether 52 had delayed responses. Fifty-one patients in the group satisfied McAlpine's criteria for diagnosing definite, probable, or possible multiple sclerosis. Of these, all but two had delayed responses in one or both eyes, while only three of the remaining 22 patients had delays. In those patients with multiple sclerosis but without any history of optic neuritis the incidence of delayed responses was only slightly less. Of 51 patients with delayed responses 23 had normal discs. Thus subclinical lesions of the visual pathways can be readily detected with this test. The high incidence of abnormal pattern responses, even in patients with no other ocular signs or symptoms, suggests that the test is of value in establishing the diagnosis.

Brain Stem↗