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Biomedical subjects

M Groenveld

Publications and source records attributed to M Groenveld.

13 recordsLinked to original sources
PubMed1998

Speech, cognition, and imaging studies in congenital ocular motor apraxia.

Detailed neurological, speech and language, psychological, and neuroimaging studies were carried out in eight children with the diagnosis of congenital ocular motor apraxia. The neurological examination showed clinical evidence of cerebellar vermis abnormality (hypotonia and truncal ataxia) in all cases. Neuroimaging studies suggested that the site of neuropathological disturbance of congenital ocular motor apraxia was the inferior vermis. Half of the subjects had associated speech apraxia. The most likely location of brain disturbance, which was responsible for the speech apraxia, was also an as yet undefined area of the vermis. Psychological testing consistently revealed visual-spatial difficulties. These may have been secondary to cerebellar pathology or to developmentally inappropriate sensory input caused by the abnormal saccades. Children with speech apraxia appear to be slightly more affected neurologically than those with normal speech.

Apraxias↗
PubMed1994

The septum pellucidum and spatial ability of children with optic nerve hypoplasia.

Animal studies suggest that spatial skills are dependent on an intact septum pellucidum. This theory was tested by comparing patients who were visually impaired due to bilateral optic nerve hypoplasia: 13 with a septum pellucidum were compared with six children without a septum pellucidum. There was no difference in spatial ability. The finding of an absent septum pellucidum may only indicate the timing of a congenital brain insult, and it cannot be used to predict specific clinical, neuroendocrinological, cognitive or spatial abnormalities.

Adolescent↗
PubMed1993

Photophobia and cortical visual impairment.

Photophobia, or intolerance of light, is not completely understood as a symptom. It has been divided into ocular and central types. This study shows that persistent, usually mild, photophobia occurs in about one-third of children with cortical visual impairment (CVI). When the CVI is congenital the photophobia is present from birth, and when it is acquired the sensitivity to light appears immediately after the brain insult. The intensity of photophobia tends to diminish with time and occasionally it may even disappear. The pathophysiology is unclear, as in all other neurological disorders associated with photophobia.

Brain↗
PubMed1990

Light-gazing by visually impaired children.

This study assessed the prevalence and characteristics of light-gazing by all visually impaired children referred during a 2 1/2-year period. Light-gazing (compulsive staring into lights) is one of the many clinical signs of cortical visual impairment (CVI), and in the present study it occurred in 60 per cent of children with CVI. The authors believe that light-gazing by any child with ocular lesions indicates some degree of CNS involvement. Visually impaired children who flicker their fingers in front of their eyes against a light source demonstrate an extension of this compulsive behaviour. This and other studies suggest that blind mannerisms have specific neuropathological substrata and therefore are useful clinical signs.

Blindness↗
PubMed1990

Head shaking by visually impaired children: a voluntary neurovisual adaptation which can be confused with spasmus nutans.

Rapid, horizontal, pendular head oscillations were observed in 18 visually impaired children with nystagmus during intense visual fixation, and the characteristics of this behaviour were analysed. Head tilting and eye deviations also occurred in 14 of the children. Their symptoms and signs resembled spasmus nutans. Head shaking appeared to be a voluntary, learned, neurovisual adaptation to improve visual acuity. Accurate simultaneous recordings of eye and head movements are required to understand the pathophysiological significance of these head oscillations.

Adolescent↗
PubMed1990

Habilitation and rehabilitation of visually impaired and blind children.

Important neurological, developmental and cognitive differences exist between the visually impaired and the sighted. Unless parents, health professionals, educators and other caregivers understand the differences, serious problems may arise. Certain aspects of development in visually impaired children have consequences for habilitation and rehabilitation.

Blindness↗
PubMed1987

Behavioural characteristics of children with permanent cortical visual impairment.

The common behavioral features of 50 children with permanent cortical visual impairment (CVI) are described. CVI is frequently associated with specific behavioural characteristics. The majority of these children have residual vision, but they all have variable and inconsistent visual performance, including visual acuity. They see better in familiar environments and when they understand what to look for and where to look for it. They often use touch to identify objects. Their ability to identify colours is much stronger than their perception of form. Many turn their heads to the side when they are reaching. Nystagmus and visual self-stimulation are exceptionally rare. They appear to have great difficulty with the cognitive evaluation of visual perception in spatial terms. Head elevation is worst in those with least vision, and without head elevation the possibility of visual stimulation is further restricted.

Adolescent↗
PubMed1983

Low flow oxygen therapy in infants.

Fifty one infants who were oxygen dependent after treatment for neonatal respiratory disease were entered into a study programme where 100% oxygen was delivered at low flow through a nasal catheter. Thirty five (69%) of the infants were discharged home and the remainder were either discharged to a convalescent hospital or back to their peripheral referring hospital. Excluding repeat admissions for monitoring or for the treatment of acute infections, 2760 hospital days (79 days/patient) were saved, representing a financial saving of $11990 (pounds 6500) per treated infant. A home low flow oxygen therapy programme has benefits to the infant/parent relationship, provides a more constant flow of oxygen than conventional methods, and the early hospital discharge represents a considerable financial saving.

Birth Weight↗
PubMedDate not supplied

Cortical visual impairment in children.

Cortical visual impairment (CVI) in children is most commonly caused by peri- or post-natal hypoxia-ischemia, but may also occur following other insults, e.g., trauma, epilepsy, infections, drugs or poisons, and certain neurologic diseases. The disorder differs considerably in etiology, physical findings, and, perhaps, prognosis, from the cortical blindness seen in adults. The same event that causes CVI by damaging the geniculate and/or extrageniculate visual pathways may also damage other areas of the brain, or the retina, optic nerves, or chiasm. Thus, children with CVI often have other neurological problems. Diagnosis may require the participation of a multidisciplinary team and the use of special visual testing techniques. Due to the uncertainty concerning the prognosis in CVI, clinicians should remain optimistic about the child's potential for some vision recovery.

Brain Damage, Chronic↗
PubMedDate not supplied

Travel vision: "collicular visual system"?

Two visually impaired children with occipital infarctions are presented. One patient has profound impairment of his primary visual pathway but has good vision for traveling, while the other child presented with the symptoms in reverse. We believe that these two patients provide further evidence that the primary visual pathway is used for conscious visual analysis and that the collicular visual system serves as the subconscious visual guidance for locomotion.

Attention↗