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See detailStimulus-dependent modulation of visual neglect in a touch-screen cancellation task
Keller, Ingo; Volkening, Katharina; Müller, Ruta UL

in Neuropsychology (2015), 29(3), 417-420

Objective: Patients with left-sided neglect frequently show omissions and repetitive behavior on cancellation tests. Using a touch-screen-based cancellation task, we tested how visual feedback and ... [more ▼]

Objective: Patients with left-sided neglect frequently show omissions and repetitive behavior on cancellation tests. Using a touch-screen-based cancellation task, we tested how visual feedback and distracters influence the number of omissions and perseverations. Method: Eighteen patients with left-sided visual neglect and 18 healthy controls performed four different cancellation tasks on an iPad touch screen: no feedback (the display did not change during the task), visual feedback (touched targets changed their color from black to green), visual feedback with distracters (20 distracters were evenly embedded in the display; detected targets changed their color from black to green), vanishing targets (touched targets disappeared from the screen). Results: Except for the condition with vanishing targets, neglect patients had significantly more omissions and perseverations than healthy controls in the remaining three subtests. Both conditions providing feedback by changing the target color showed the highest number of omissions. Erasure of targets nearly diminished omissions completely. The highest rate of perseverations was observed in the no-feedback condition. The implementation of distracters led to a moderate number of perseverations. Visual feedback without distracters and vanishing targets abolished perseverations nearly completely. Conclusions: Visual feedback and the presence of distracters aggravated hemispatial neglect. This finding is compatible with impaired disengagement from the ipsilesional side as an important factor of visual neglect. Improvement of cancellation behavior with vanishing targets could have therapeutic implications. [less ▲]

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See detailNeurofeedback in three patients in the state of unresponsive wakefulness
Keller, Ingo; Müller, Ruta UL

in Applied Psychophysiology and Biofeedback (2015), 40(4), 349-356

Some severely brain injured patients remain unresponsive, only showing reflex movements without any response to command. This syndrome has been named unresponsive wakefulness syndrome (UWS). The objective ... [more ▼]

Some severely brain injured patients remain unresponsive, only showing reflex movements without any response to command. This syndrome has been named unresponsive wakefulness syndrome (UWS). The objective of the present study was to determine whether UWS patients are able to alter their brain activity using neurofeedback (NFB) technique. A small sample of three patients received a daily session of NFB for 3 weeks. We applied the ratio of theta and beta amplitudes as a feedback variable. Using an automatic threshold function, patients heard their favourite music whenever their theta/beta ratio dropped below the threshold. Changes in awareness were assessed weekly with the JFK Coma Recovery Scale-Revised for each treatment week, as well as 3 weeks before and after NFB. Two patients showed a decrease in their theta/beta ratio and theta-amplitudes during this period. The third patient showed no systematic changes in his EEG activity. The results of our study provide the first evidence that NFB can be used in patients in a state of unresponsive wakefulness. [less ▲]

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