1,721,337 research outputs found
Towards enhancement of motor recovery in the upper limb after stroke
No full textItem does not contain fulltextUniversity Tübingen, 26 september 2014Promotor : Birbaumer, N
Conditional associative learning examined in a paralyzed patient with amyotrophic lateral sclerosis using brain-computer interface technology
Full text linkBackground Brain-computer interface methodology based on self-regulation of slow-cortical potentials (SCPs) of the EEG (electroencephalogram) was used to assess conditional associative learning in one severely paralyzed, late-stage ALS patient. After having been taught arbitrary stimulus relations, he was evaluated for formation of equivalence classes among the trained stimuli. Methods A monitor presented visual information in two targets. The method of teaching was matching to sample. Three types of stimuli were presented: signs (A), colored disks (B), and geometrical shapes (C). The sample was one type, and the choice was between two stimuli from another type. The patient used his SCP to steer a cursor to one of the targets. A smiley was presented as a reward when he hit the correct target. The patient was taught A-B and B-C (sample – comparison) matching with three stimuli of each type. Tests for stimulus equivalence involved the untaught B-A, C-B, A-C, and C-A relations. An additional test was discrimination between all three stimuli of one equivalence class presented together versus three unrelated stimuli. The patient also had sessions with identity matching using the same stimuli. Results The patient showed high accuracy, close to 100%, on identity matching and could therefore discriminate the stimuli and control the cursor correctly. Acquisition of A-B matching took 11 sessions (of 70 trials each) and had to be broken into simpler units before he could learn it. Acquisition of B-C matching took two sessions. The patient passed all equivalence class tests at 90% or higher. Conclusion The patient may have had a deficit in acquisition of the first conditional association of signs and colored disks. In contrast, the patient showed clear evidence that A-B and B-C training had resulted in formation of equivalence classes. The brain-computer interface technology combined with the matching to sample method is a useful way to assess various cognitive abilities of severely paralyzed patients, who are without reliable motor control
A brief and unobtrusive instrument to detect simulation and exaggeration in patients with whiplash syndrome
No full textThe objective of this study was to develop and test a brief and unobtrusive instrument to detect exaggeration and simulation in whiplash syndrome. The instrument consists of eight scenarios with ten response options that have to be ordered according to how easy a behavior is to perform. Twenty-five simulating and 25 non-simulating patients with whiplash syndrome of grades 2 and 3 according to the Quebec Task Force classification as well as 25 simulating and 25 non-simulating controls completed the instrument. In a cross-validation study 20 controls and 20 patients participated. Malingering and exaggeration scores were determined for each subject and patient. The scores were summed up and compared across malingering and exaggerating subjects and controls and cut-off values were determined to classify the patients. T-tests and a discriminant analysis were used to determine classification accuracy. The instrument correctly identified 94% of the simulators and 84% of the exaggerators in both samples. This brief and unobtrusive instrument can detect exaggeration and simulation in whiplash syndrome. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved
BARORECEPTOR CORTICAL EFFECTS, EMOTIONS AND PAIN
No full textThe specificity of baroreceptor-dependent inhibition of pain reactions to electrical stimuli was investigated during induction of different emotional states in 27 subjects. Baroreceptors were stimulated through the PRES (Phase Related External Suction) technique, while emotions were induced by means of pleasant, neutral and unpleasant slides. The dependent variables were pain ratings, somatic evoked potentials (N150 and P260) recorded from Fz, Cz and Pz, and skin conductance response (SCR), while heart rate was recorded as a PRES requirement. Valence and arousal ratings were obtained in front of each slide. During suction (external baroreceptor activation) reduced pain ratings, cortical disfacilitation (from Pz, as revealed by N150) and lower SCR were found as compared to pressure (baroreceptor deactivation). Moreover, brain evoked potentials (N150 and P260) reflecting cortical inhibition were found under condition of baroreceptor stimulation during unpleasant slides, but not during pleasant or neutral ones: this result was found in the high blood pressure subjects only. Data showed also a valence effect on pain ratings: pain was evaluated to be higher during unpleasant slides, than neutral and pleasant ones. Results are discussed in the light of ''baroreceptor reward'' hypothesis, which proposes a learning mechanism for the development of essential hypertension
Category-specific semantic impairment in Alzheimer's disease and temporal lobe dysfunction: A comparative study
No full textMapping encoding and retrieval of melodic and rhythmic redundancies in music processing: An fMRI study
No full textLooking for the neural bases of memory systems during the processing of music: An event-related fMRI study.
No full text
- …
