Biomedical subjects

Peter Hansen

Publications and source records attributed to Peter Hansen.

8 recordsLinked to original sources

PubMed2024

A corpus of GA4GH phenopackets: Case-level phenotyping for genomic diagnostics and discovery.

The Global Alliance for Genomics and Health (GA4GH) Phenopacket Schema was released in 2022 and approved by ISO as a standard for sharing clinical and genomic information about an individual, including phenotypic descriptions, numerical measurements, genetic information, diagnoses, and treatments. A phenopacket can be used as an input file for software that supports phenotype-driven genomic diagnostics and for algorithms that facilitate patient classification and stratification for identifying new diseases and treatments. There has been a great need for a collection of phenopackets to test software pipelines and algorithms. Here, we present Phenopacket Store. Phenopacket Store v.0.1.19 includes 6,668 phenopackets representing 475 Mendelian and chromosomal diseases associated with 423 genes and 3,834 unique pathogenic alleles curated from 959 different publications. This represents the first large-scale collection of case-level, standardized phenotypic information derived from case reports in the literature with detailed descriptions of the clinical data and will be useful for many purposes, including the development and testing of software for prioritizing genes and diseases in diagnostic genomics, machine learning analysis of clinical phenotype data, patient stratification, and genotype-phenotype correlations. This corpus also provides best-practice examples for curating literature-derived data using the GA4GH Phenopacket Schema.

Humans↗

PubMed2006

Attentional shifting and the role of the dorsal pathway in visual word recognition.

A substantial amount of evidence has been collected to propose an exclusive role for the dorsal visual pathway in the control of guided visual search mechanisms, specifically in the preattentive direction of spatial selection [Vidyasagar, T. R. (1999). A neuronal model of attentional spotlight: Parietal guiding the temporal. Brain Research and Reviews, 30, 66-76; Vidyasagar, T. R. (2001). From attentional gating in macaque primary visual cortex to dyslexia in humans. Progress in Brain Research, 134, 297-312]. Moreover, it has been suggested recently that the dorsal visual pathway is specifically involved in the spatial selection and sequencing required for orthographic processing in visual word recognition. In this experiment we manipulate the demands for spatial processing in a word recognition, lexical decision task by presenting target words in a normal spatial configuration, or where the constituent letters of each word are spatially shifted relative to each other. Accurate word recognition in the Shifted-words condition should demand higher spatial encoding requirements, thereby making greater demands on the dorsal visual stream. Magnetoencephalographic (MEG) neuroimaging revealed a high frequency (35-40Hz) right posterior parietal activation consistent with dorsal stream involvement occurring between 100 and 300ms post-stimulus onset, and then again at 200-400ms. Moreover, this signal was stronger in the shifted word condition, compared to the normal word condition. This result provides neurophysiological evidence that the dorsal visual stream may play an important role in visual word recognition and reading. These results further provide a plausible link between early stage theories of reading, and the magnocellular-deficit theory of dyslexia, which characterises many types of reading difficulty.

Attention↗

PubMed2006

Motion and form coherence detection in autistic spectrum disorder: Relationship to motor control and 2:4 digit ratio.

Children with autistic spectrum disorder and controls performed tasks of coherent motion and form detection, and motor control. Additionally, the ratio of the 2nd and 4th digits of these children, which is thought to be an indicator of foetal testosterone, was measured. Children in the experimental group were impaired at tasks of motor control, and had lower 2D:4D than controls. There were no group differences in motion or form detection. However a sub-group of children with autism were selectively impaired at motion detection. There were significant relationships between motion coherence detection and motor control in both groups of children, and also between motion detection, fine motor control and 2D:4D in the group of children with autistic spectrum disorder.

Asperger Syndrome↗

PubMed2006

The role of sensorimotor impairments in dyslexia: a multiple case study of dyslexic children.

This study attempts to investigate the role of sensorimotor impairments in the reading disability that characterizes dyslexia. Twenty-three children with dyslexia were compared to 22 control children, matched for age and non-verbal intelligence, on tasks assessing literacy as well as phonological, visual, auditory and motor abilities. The dyslexic group as a whole were significantly impaired on phonological, but not sensorimotor, tasks. Analysis of individual data suggests that the most common impairments were on phonological and visual stress tasks and the vast majority of dyslexics had one of these two impairments. Furthermore, phonological skill was able to account for variation in literacy skill, to the exclusion of all sensorimotor factors, while neither auditory nor motor skill predicted any variance in phonological skill. Visual stress seems to account for a small proportion of dyslexics, independently of the commonly reported phonological deficit. However, there is little evidence for a causal role of auditory, motor or other visual impairments.

Child↗

PubMed2005

Speechreading skill and visual movement sensitivity are related in deaf speechreaders.

Individual speechreading abilities have been linked with a range of cognitive and language-processing factors. The role of specifically visual abilities in relation to the processing of visible speech is less studied. Here we report that the detection of coherent visible motion in random-dot kinematogram displays is related to speechreading skill in deaf, but not in hearing, speechreaders. A control task requiring the detection of visual form showed no such relationship. Additionally, people born deaf were better speechreaders than hearing people on a new test of silent speechreading.

Adolescent↗

PubMed2004

Magnocellular mediated visual-spatial attention and reading ability.

This study explores the relationship between attentional processing mediated by visual magnocellular (MC) processing and reading ability. Reading ability in a group of primary school children was compared to performance on a visual cued coherent motion detection task. The results showed that a brief spatial cue was more effective in drawing attention either away or towards a visual target in the group of readers ranked in the upper 25% of the sample compared to lower ranked readers. Regression analysis showed a significant relationship between attentional processing and reading when the effects of age and intellectual ability were removed. Results suggested a stronger relationship between visual attentional and non-word reading compared to irregular word reading.

Analysis of Variance↗

PubMed2004

Symbol-string sensitivity and children's reading.

In this study of primary school children, a novel 'symbol-string' task is used to assess sensitivity to the position of briefly presented non-alphabetic but letter-like symbols. The results demonstrate that sensitivity in the symbol-string task explains a unique proportion of the variability in children's contextual reading accuracy. Moreover, developmental dyslexic readers show reduced sensitivity in this task, compared to chronological age controls. The results suggest that limitations set by visuo-spatial processes and/or attentional iconic memory resources may constrain children's reading accuracy.

Attention↗

PubMed2002

High motion coherence thresholds in children with autism.

BACKGROUND: We assessed motion processing in a group of high functioning children with autism and a group of typically developing children, using a coherent motion detection task. METHOD: Twenty-five children with autism (mean age 11 years, 8 months) and 22 typically developing children matched for non-verbal mental ability and chronological age were required to detect the direction of moving dots in a random dot kinematogram. RESULTS: The group of children with autism showed significantly higher motion coherence thresholds than the typically developing children (i.e., they showed an impaired ability to detect coherent motion). CONCLUSIONS: This finding suggests that some individuals with autism may show impairments in low-level visual processing--specifically in the magnocellular visual pathway. The findings are discussed in terms of implications for higher-level cognitive theories of autism, and the suggestion is made that more work needs to be carried out to further investigate low-level visual processing in autism.

Adolescent↗