Biomedical subjects

Elfriede Karner

Publications and source records attributed to Elfriede Karner.

3 recordsLinked to original sources

PubMed2005

Language and arithmetic--a study using the intracarotid amobarbital procedure.

The intracarotid amobarbital procedure is used as a standard procedure in presurgical evaluation to assess hemispheric lateralization of language and memory, but has not been applied to investigate numerical processing. Patients with medically intractable epilepsy (n=20) were consecutively recruited during a presurgical evaluation programme. All 14 patients with left-lateralized language showed better arithmetic performance with the left hemisphere (intracarotid amobarbital procedure right), while five out of six patients with bilateral or right-hemispheric language representation showed better performance with the right hemisphere (intracarotid amobarbital procedure left). Furthermore, in patients with left-lateralized language, an interaction between intracarotid amobarbital procedure and type of arithmetic operation was found. The study suggests a close association between language lateralization and hemispheric specialization for arithmetic processing.

Adult↗

PubMed2004

Number processing and basal ganglia dysfunction: a single case study.

Numerical processing has never been investigated in a case of Fahr's disease (FD) and only rarely in cases of basal ganglia dysfunction. The study describes the cognitive decline of a pre-morbidly high-functioning patient (medical doctor) affected by FD and his difficulties in number processing. A MRI scan revealed bilateral calcifications in the basal ganglia and a brain PET showed a massive reduction of glucose metabolism in the basal ganglia and both frontal lobes, but no other brain abnormalities. The patient's cognitive deficits included impairments in problem solving, in cognitive set shifting and in mental flexibility, as well as in verbal memory. These deficits are attributed to the disruption of the dorsolateral prefrontal circuit involving the basal ganglia. In number processing, the patient showed a severe deficit in the retrieval of multiplication facts, deficits in all tasks of numerical problem solving and in the execution of complex procedures. Importantly, he also showed a dense deficit in conceptual knowledge, which concerned all test conditions and all operations. The findings confirm the predictions of the triple code model in so far, as a disruption of cortico-subcortical loops involving the basal-ganglia may lead to specific deficits in fact retrieval. However, no verbal deficit, as assumed in the triple code model and reported in similar cases, could be observed. The present findings further add to current knowledge on numerical processing, showing how fronto-executive dysfunction may disrupt conceptual understanding of arithmetic. This study shows that not only parietal lesions may lead to severe deficits in conceptual understanding, but that basal ganglia lesions leading to frontal dysfunction may have a devastating effect.

Basal Ganglia Diseases↗

PubMed2002

The neuropsychological assessment of dementia.

It has become standard practice to base the diagnosis of dementia on the combination of neuropsychological and non-behavioral findings. The present article provides a short, clinically oriented synopsis of the targets, investigational procedures, and difficulties of the modern neuropsychological approach to the diagnosis of dementia. Over the years, neuropsychology has developed assessment tools to evaluate the cognitive and behavioral abnormalities of many dementias. Validated tests of memory, language, executive, and other cognitive functions are used to screen for dementia and identifying certain dementia profiles. Behavioral assessment procedures are available for non-cognitive neurodegenerative alterations. At present, problems arise mainly with the behavioral heterogeneity of certain dementia syndromes. Especially problematic are discrimination of age-associated or mild cognitive impairments from incipient dementia and the impact of psychiatric symptoms on cognitive functions. It is concluded that neuropsychology offers a valuable contribution to the diagnosis and differential diagnosis of dementia.

Journal Article↗