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See detailAttentional Impairments in Huntington’s Disease: A Specific Deficit for the Executive Conflict
Maurage, Pierre; Heeren, Alexandre; Lahaye, Magali et al

in Neuropsychology (2017), 31(4), 424-436

Objective: Huntington’s disease (HD) is characterized by motor and cognitive impairments including memory, executive, and attentional functions. However, because earlier studies relied on multidetermined ... [more ▼]

Objective: Huntington’s disease (HD) is characterized by motor and cognitive impairments including memory, executive, and attentional functions. However, because earlier studies relied on multidetermined attentional tasks, uncertainty still abounds regarding the differential deficit across attentional subcomponents. Likewise, the evolution of these deficits during the successive stages of HD remains unclear. The present study simultaneously explored 3 distinct networks of attention (alerting, orienting, executive conflict) in preclinical and clinical HD. Method: Thirty-eight HD patients (18 preclinical) and 38 matched healthy controls completed the attention network test, an integrated and theoretically grounded task assessing the integrity of 3 attentional networks. Results: Preclinical HD was not characterized by any attentional deficit compared to controls. Conversely, clinical HD was associated with a differential deficit across the 3 attentional networks under investigation, showing preserved performance for alerting and orienting networks but massive and specific impairment for the executive conflict network. This indexes an impaired use of executive control to resolve the conflict between task-relevant stimuli and interfering task-irrelevant ones. Conclusion: Clinical HD does not lead to a global attentional deficit but rather to a specific impairment for the executive control of attention. Moreover, the absence of attentional deficits in preclinical HD suggests that these deficits are absent at the initial stages of the disease. In view of their impact on everyday life, attentional deficits should be considered in clinical contexts. Therapeutic programs improving the executive control of attention by neuropsychology and neuromodulation should be promoted. [less ▲]

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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 detailPerceptual relearning of binocular fusion after hypoxic brain damage: Four controlled single-case treatment studies
Schaadt, Anna-Katharina; Schmidt, Lena; Kuhn, Caroline et al

in Neuropsychology (2014), 28(3), 382-387

OBJECTIVE: Hypoxic brain damage is characterized by widespread, diffuse-disseminated brain lesions, which may cause severe disturbances in binocular vision, leading to diplopia and loss of stereopsis, for ... [more ▼]

OBJECTIVE: Hypoxic brain damage is characterized by widespread, diffuse-disseminated brain lesions, which may cause severe disturbances in binocular vision, leading to diplopia and loss of stereopsis, for which no evaluated treatment is currently available. The study evaluated the effects of a novel binocular vision treatment designed to improve binocular fusion and stereopsis as well as to reduce diplopia in patients with cerebral hypoxia. METHOD: Four patients with severely reduced convergent fusion, stereopsis, and reading duration due to hypoxic brain damage were treated in a single-subject baseline design, with three baseline assessments before treatment to control for spontaneous recovery (pretherapy), an assessment immediately after a treatment period of 6 weeks (posttherapy), and two follow-up tests 3 and 6 months after treatment to assess stability of improvements. Patients received a novel fusion and dichoptic training using 3 different devices designed to slowly increase fusional and disparity angle. RESULTS: After the treatment, all 4 patients improved significantly in binocular fusion, subjective reading duration until diplopia emerged, and 2 of 4 patients improved significantly in local stereopsis. No significant changes were observed during the pretherapy baseline period and the follow-up period, thus ruling out spontaneous recovery and demonstrating long-term stability of treatment effects. CONCLUSIONS: This proof-of-principle study indicates a substantial treatment-induced plasticity after hypoxia in the relearning of binocular vision and offers a viable treatment option. Moreover, it provides new hope and direction for the development of effective rehabilitation strategies to treat neurovisual deficits resulting from hypoxic brain damage. [less ▲]

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See detailCognitive control in adolescents with Neurofibromatosis Type 1
Rowbotham, I.; Pit-Ten Cate, Ineke UL; Sonuga-Barke, E. J. S. et al

in Neuropsychology (2009), 23

Neurofibromatosis Type 1 (NF1) is a genetic disorder characterized by partial loss of growth control that affects the central nervous system. NF1 has been consistently associated with cognitive ... [more ▼]

Neurofibromatosis Type 1 (NF1) is a genetic disorder characterized by partial loss of growth control that affects the central nervous system. NF1 has been consistently associated with cognitive dysfunction, although there is no consensus on the cognitive profile in NF1 or on brain-cognition relationships. To clarify the pattern of cognitive dysfunction, performance of 16 NF1 patients and 16 age- and sex-matched controls (mean age = 14.5 years, SD = 1.3) was compared on computerized tasks measuring perception, executive functioning (inhibitory control, cognitive flexibility, and working memory), and motor control. A further aim of this study was to contrast performance on tasks or task parts requiring varying levels of cognitive control to find out whether this could explain potential difficulties experienced by this population in different cognitive domains or at different stages of information processing. Repeated measures analyses of variance showed that group differences, indicating poorer performance of NF1 patients, varied as a function of the level of cognitive control required. Evidence was also found for more basic motor skill problems in NF1 patients. Furthermore, NF1 patients were generally slower than controls. Results are discussed in the context of what is known about brain-cognition relationships in NF1. [less ▲]

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