Exploring eye movement analysis as a measure of selective visual attention in brain injured individuals

Primary Objective: To investigate the utility of using a new method of assessment for deficits in selective visual attention (SVA). Methods and Procedures: An independent groups design compared six participants with brain injuries with six participants from a non-brain injured control group. The Sensomotoric Instruments Eye Movement system with remote eye-tracking device (eye camera), and 2 sets of eight stimuli were employed to determine if the camera would be a sensitive discriminator of SVA in these groups. Main Outcomes and Results: The attention profile displayed by the brain injured group showed that they were slower, made more errors, were less accurate, and more indecisive than the control group. Conclusions: The utility of eye movement analysis as an assessment method was established, with implications for rehabilitation requiring further development. Key words: selective visual attention, eye movement analysis, brain injury

Attitudes of children towards peers with acquired brain injury (ABI).

Research objective: Children with acquired brain injury (ABI) can experience severe problems in establishing peer relationships. The attitudes peers hold toward a child with an ABI can significantly impact on their willingness to befriend. The present work sought to investigate the attitudes peers hold toward a fictional child with ABI. Methods and procedures: Fifty children from a primary school were compared against a similar number from a secondary school. Gender was evenly split across both groups. A vignette describing a young boy acquiring a brain injury, and his subsequent change in behaviour, was presented to the children. The Friendship Activity Scale (FAS) was then used to judge how likely the children were to befriend the fictional character. Outcomes and results: Results showed a statistically significant interaction between gender and age [F(1, 96) 6.285, p = 0.014] with older males expressing more positive attitudes than younger males. Conclusion: The study suggests that children with ABI are more likely to experience negative attitudes in primary school, and concludes in calling for additional research to more fully explore the social experience of children with ABI. Keywords: Children; acquired brain injury; peers; attitudes

Trends in the prevalence of cerebral palsy in Northern Ireland, 1981-1997

We describe trends in the prevalence of cerebral palsy (CP) by birth weight group, and in the severity of motor impairments and presence of associated intellectual impairment, in Northern Ireland from 1981 to 1997 (n=909; 510 males, 399 females; total population 415 936 live births) using data from a population-based register of CP. Children with suspected CP or who died before 1 year of age and those with CP of postneonatal origin were excluded. Prevalence of CP was 2.2 per 1000 live births without significant change over time. Among very-low-birthweight (<1500g) live births, prevalence was 44.5 per 1000 (95% confidence interval 32.3–59.8) from 1994 to 1997, with evidence of a statistically significant decline in prevalence since the mid- to late 1980s accompanied by a decrease in the severity of motor impairment and likelihood of intellectual impairment. Among moderately-low-birthweight (1500–2499g) children there was weaker evidence of a peak prevalence in the late 1980s. Prevalence among normal-birthweight infants did not change significantly, but outcome in terms of severity of motor impairment and intellectual impairment improved in the 1990s. Occurrence of bilateral spasticity from 1994 to 1997 was associated with greater severity and likelihood of intellectual impairment for normal-birthweight individuals than for low- or very-low-birth weight individuals.

Glutamate transporters in platelets: EAAT1 decrease in aging and in Alzheimer's disease.

Platelets release glutamate upon activation and are an important clearance system of the amino acid from blood, through high-affinity glutamate uptake, similar to that described in brain synaptosomes. Since platelet glutamate uptake is decreased in neurodegenerative disorders, we performed a morphological and molecular characterization of platelet glutamate transporters. The three major brain glutamate transporters EAAT1, EAAT2 and EAAT3 are expressed in platelets, with similar molecular weight, although at lower density than brain. A Na(+)-dependent-high-affinity glutamate uptake was competitively inhibited by known inhibitors but not by dihydrokainic acid, suggesting platelet EAAT2 does not play a major role in glutamate uptake at physiological conditions. We observed decreased glutamate uptake V(max), without modification of transporter affinity, in aging, which could be linked to the selective decrease of EAAT1 expression and mRNA. Moreover, in AD patients we found a further EAAT1 reduction compared to age-matched controls, which could explain the decrease of platelet uptake previously described. Platelet glutamate transporters may be used as peripheral markers to investigate the role of glutamate in patients with neuropsychiatric disorders.

Detection of cathepsin S cysteine protease in human brain tumour microdialysates in vivo.

Microdialysis enables the chemistry of extracellular ?uid in body tissues to be measured. Extracellular proteases such as the cysteine protease, cathepsin S (CatS), are thought to facilitate astrocytoma invasion. Microdialysates obtained from human brain tumoursin vivo were subjected to cathepsin S activity and ELISA assays. Cathepsin S ELISA expression was detected in ?ve out of 10 tumour microdialysates, while activity was detected in ?ve out of 11 tumour microdialysates. Cathepsin S expression was also detected in microdialysate from the normal brain control although no activity was found in the same sample. While some re?nements to the technique are necessary, the authors demonstrate the feasibility and safety of microdialysis in human astrocytomasin vivo. Characterisation of the extracellular environment of brain tumoursin vivo using microdialysis may be a useful tool to identify the protease pro?le of brain tumours.