Accelerating P300-based neurofeedback training for attention enhancement using iterative learning control: a randomised controlled trial.

Objective. Neurofeedback (NFB) training through brain-computer interfacing has demonstrated efficacy in treating neurological deficits and diseases, and enhancing cognitive abilities in healthy individuals. It was previously shown that event-related potential (ERP)-based NFB training using a P300 speller can improve attention in healthy adults by incrementally increasing the difficulty of the spelling task. This study aims to assess the impact of task difficulty adaptation on ERP-based attention training in healthy adults. To achieve this, we introduce a novel adaptation employing iterative learning control (ILC) and compare it against an existing method and a control group with random task difficulty variation.Approach. The study involved 45 healthy participants in a single-blind, three-arm randomised controlled trial. Each group underwent one NFB training session, using different methods to adapt task difficulty in a P300 spelling task: two groups with personalised difficulty adjustments (our proposed ILC and an existing approach) and one group with random difficulty. Cognitive performance was evaluated before and after the training session using a visual spatial attention task and we gathered participant feedback through questionnaires.Main results. All groups demonstrated a significant performance improvement in the spatial attention task post-training, with an average increase of 12.63%. Notably, the group using the proposed iterative learning controller achieved a 22% increase in P300 amplitude during training and a 17% reduction in post-training alpha power, all while significantly accelerating the training process compared to other groups.Significance. Our results suggest that ERP-based NFB training using a P300 speller effectively enhances attention in healthy adults, with significant improvements observed after a single session. Personalised task difficulty adaptation using ILC not only accelerates the training but also enhances ERPs during the training. Accelerating NFB training, while maintaining its effectiveness, is vital for its acceptability by both end-users and clinicians.

Keratoses in patients with psoriasis: a prospective study in fifty-two inpatients.

Twenty-eight of 52 consecutive psoriasis inpatients admitted for therapy with the modified Goeckerman regimen had discrete, gray-white, asymptomatic, keratotic lesions approximately 4 mm in diameter at discharge from the hospital. In 18 of these 28 patients no keratoses were noted on admission. In 9 of 10 patients who had keratoses at admission, there was an increase in number at discharge. All patients with keratoses on admission had multiple, closely spaced previous admissions. No age, sex, or skin type predominance was evident in the group with keratoses compared with the remainder of the group (24 patients) who did not have keratoses. The development of keratoses was not related to the type or duration of psoriasis. Statistically significant predisposing factors were the number of UVB and PUVA treatments and the number of inpatient admissions. Fifty-two percent were located on the extremities, 33% on the trunk, and 15% on the face, head, and neck. Histologic examination of these lesions suggested that they may be a variant of seborrheic keratoses. We have not seen these lesions on patients receiving UVB, PUVA, or tar therapy for other diseases. This raises the possibility that these lesions may be unique to psoriasis and most likely are related to long-term therapy.