Biomedical subjects

D Yves Von Cramon

Publications and source records attributed to D Yves Von Cramon.

6 recordsLinked to original sources

PubMed2006

Reduced daytime activity in patients with acquired brain damage and apathy: a study with ambulatory actigraphy.

PRIMARY OBJECTIVE: Apathy is difficult to assess in clinical practice. Ambulatory actigraphy was used with the aim to measure locomotor activity during the daytime as a correlate of self-initiated action in brain-damaged patients with apathy. RESEARCH DESIGN: Twenty-four patients with acquired brain damage and high levels of apathy or low levels of apathy as well as 12 healthy controls were investigated using a parallel group design. METHODS AND PROCEDURES: Apathy was diagnosed after clinical observation and evaluated with the apathy evaluation scale. Locomotor activity was measured with a wrist-worn actigraph over 3 days. RESULTS: High apathy patients showed significantly reduced locomotor activity and more episodes of inactivity (naps) during the daytime. Self-rated apathy correlated with daytime activity, nap frequency and cognitive (executive) deficits. CONCLUSIONS: Ambulatory actigraphy is a promising method to evaluate self-initiated action in patients with apathy.

Adult↗

PubMed2003

Determination of cerebrovascular reactivity by means of FMRI signal changes in cerebral microangiopathy: a correlation with morphological abnormalities.

BACKGROUND AND PURPOSE: A reduced cerebrovascular reactivity (CR) is a risk factor of cerebrovascular disease. In this study, we implemented a protocol to assess CR by means of functional MRI (fMRI) using hyperventilation. SUBJECTS AND METHODS: In 5 patients with cerebral microangiopathy (CM/lacunar infarction and white matter degeneration), 6 healthy elderly subjects (age-matched control), and 6 young healthy subjects, the CR in response to hyperventilation was evaluated by fMRI using gradient echo-planar Imaging. The percentage signal change normalized by end-tidal CO(2) value was measured in various brain regions. RESULTS: All subjects performed hyperventilation well without adverse reaction and significant gross motion. Patients with CM showed significant qualitative and quantitative differences (p < 0.05) as compared to controls. The volume of gray matter showing significant CR was significantly reduced in patients: by 40% in comparison to the age-matched elderly control group and by 60% when compared with the young controls. The CR impairment was most pronounced in the frontal cortices with a drastically reduced magnitude of the magnetic resonance (MR) signal change in the patients (-0.62 +/- 0.2% in patients versus -2.0 +/- 0.36% in age-matched controls, p < 0.0001). A strong relation was evident between the fMRI-based CR reduction in patients with CM and the individual severity of structural MR abnormalities (p = 0.002). CONCLUSION: This study demonstrates that fMRI-based signal changes in response to hyperventilation reliably reflect cerebral vasoreactivity. The protocol is feasible in healthy young and elderly controls and patients with CM. Quantitative and qualitative assessment of the signal decrease in the T(2)-weighted MR sequence and coregistration with individual anatomical data allow the generation of an individual cerebral vasoreactivity map. Future research will address the effect of CR reduction on neuropsychological parameters in patients with CM.

Adult↗

PubMed2002

Do quiescent arachnoid cysts alter CNS functional organization?: A fMRI and morphometric study.

OBJECTIVE: To investigate whether congenital and clinically quiescent arachnoid cysts (AC) in the left temporal fossa alter the functional organization of adjacent cortices. METHODS: fMRI mapping was applied in five right-handed asymptomatic patients to determine the functional organization of language. Moreover, morphometry was performed in each patient to gain the size of cortical surface areas and cortical thickness values in the neighboring brain adjacent to the AC and explicitly in the left opercular region. RESULTS: Four patients showed a clear left hemisphere language dominance regardless of the cyst size; a mixed laterality of language organization was found in the remaining patient. An interesting dissociation of morphometric data was assessed when comparing strongly language-related cortices in the inferior frontal gyrus with the entire neighboring cortices. Morphometry in the neighboring brain regions of the AC showed 1) overall reduced cortical surface areas and 2) a decrease in cortical thickness compared to the homologous right side. However, the surface area of the fronto-opercular region in the left inferior frontal gyrus-i.e., the pars triangularis and the pars opercularis-was larger on the left as compared to the right side. Both structures have earlier been identified to represent the morphologic substrate of language dominance in the left hemisphere. CONCLUSION: Arachnoid cysts do not disturb the normal asymmetry of hemisphere language organization despite delicate locations adjacent to the left inferior frontal gyrus.

Adult↗

PubMed2002

Localization of executive functions in dual-task performance with fMRI.

We report a study that investigated the neuroanatomical correlates of executive functions in dual-task performance with functional magnetic resonance imaging. Participants performed an auditory and a visual three-choice reaction task either separately as single tasks or concurrently as dual tasks. In the dual-task condition, two stimuli were presented in rapid succession to ensure interference between the component tasks (psychological refractory period). The behavioral data showed considerable performance decrements in the dual-task compared to the single-task condition. Dual-task-related activation was detected with two different neuroimaging methods. First, we determined dual-task-related activation according to the method of cognitive subtraction. For that purpose, activation in the dual-task was compared directly with activation in the single-task conditions. This analysis revealed that cortical areas along the inferior frontal sulcus (IFS), the middle frontal gyrus (MFG), and the intraparietal sulcus (IPS) are involved in dual-task performance. The results of the subtraction method were validated with the method of parametric manipulation. For this purpose, a second dual-task condition was introduced, where the difficulty of the dual-task coordination was increased compared with the first dual-task condition. As expected, behavioral dual-task performance decreased with increased dual-task difficulty. Furthermore, the increased dual-task difficulty led to an increase of activation in those cortical regions that proved to be dual-task related with the subtraction method, that is, the IFS, the MFG, and the IPS. These results support the conclusion that dorsolateral prefrontal and superior parietal cortices are involved in the coordination of concurrent and interfering task processing.

Acoustic Stimulation↗

PubMed2002

Separable neuronal circuitries for manipulable and non-manipulable objects in working memory.

Previous work using single-cell recordings in monkeys and neuro-imaging studies in humans has shown that perceiving an object or imaging the action associated with the object recruits the same brain regions in the ventral premotor cortex as performing an action with the object. We used functional magnetic resonance imaging (fMRI) for examining whether similar brain regions are also activated while maintaining information about manipulable objects in working memory. Holding information about manipulable objects in working memory activated the left ventral premotor cortex and the left inferior frontal gyrus (Broca's area). Conversely, non-manipulable objects to be held in working memory co-activated Broca's area and the left angular gyrus. When contrasted directly, manipulable relative to non-manipulable objects activated the left ventral premotor cortex and the anterior intraparietal sulcus, a circuitry that is assumed to mediate the transformation of movement-relevant object properties into hand actions. These results indicate that visual working memory for manipulable objects is based on motor programmes associated with their use. Similar to speech motor programmes in verbal memory tasks, hand motor programmes may allow the maintenance of objects in working memory over short intervals.

Adult↗

PubMed1996

Clients' view of neuropsychological rehabilitation.

Postacute neuropsychological rehabilitation cannot be done successfully without the personal engagement of the brain-injured client. However, systematically collected data referring to clients' satisfaction with rehabilitation programmes are rare. In this study a structured interview was developed to assess various aspects of treatment evaluation by clients. In addition, handicap was judged by primary therapists. An aetiologically mixed sample of 130 mildly to moderately brain-injured clients undergoing a comprehensive neuropsychological rehabilitation programme was investigated. About two-thirds of the sample seemed content with the training programmes whereas a minority (13%) of mostly highly handicapped persons reported being largely discontented. In this respect no differences between cognitive, speech/language, and physical therapies were found. Even though many subjects were satisfied with the programme, a majority of clients desired a substantial amelioration in the future (80%), judged their life quality as reduced in comparison to the time preceding brain injury (77%), reported difficulties in accepting 'deficits' (52%), and were frightened of becoming dependent on others (52%).

Adolescent↗