Journal of neurology, neurosurgery, and psychiatry
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Hemianopia commonly complicates stroke and, less frequently, head injury and brain tumours. Patients' activities of daily living are often affected although these can be ameliorated by appropriate behavioural therapy. Identifying a field defect is the first step in the rehabilitation process. An online visual field test (an 'app') was developed as part of a free to use web based therapy site for patients with hemianopic alexia, called Read-Right (http://www.readright.ucl.ac.uk). This study is an attempt to validate this test by comparing with a clinical 'gold standard'-the Humphrey automated visual field analyser. ⋯ Read-Right is not designed to replace standardised visual perimetry; it does, however, offer a quick and easy assessment that can be used to screen patients. The test is available as part of two free to use web based therapy applications.
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J. Neurol. Neurosurg. Psychiatr. · Dec 2012
Neuroanatomical substrates of visual hallucinations in patients with non-demented Parkinson's disease.
Visual hallucinations (VH), which are common in patients with Parkinson's disease (PD), lead to increased disability and are a significant predictor of the development of dementia. However, the neuroanatomical basis for VH in non-demented PD patients remains controversial. ⋯ The present study demonstrates that non-demented PD patients with VH exhibited a smaller volume in the frontal, temporal and thalamic areas as well as the SI, suggesting that PD hallucinators may have distinctive neuroanatomical bases relative to PD non-hallucinators.
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J. Neurol. Neurosurg. Psychiatr. · Dec 2012
Differential susceptibility to motor impulsivity among functional subtypes of Parkinson's disease.
Parkinson's disease patients with predominant postural instability and gait difficulties (PIGD) may experience unique cognitive difficulties compared to patients with tremor predominant (TD) symptoms. PIGD patients are also at high risk for falling, and some of the worst fallers seem to react impulsively to their environment. We tested the hypothesis that PIGD patients show poorer control over motor impulses compared to TD patients. ⋯ PD patients with PIGD predominant symptoms show greater susceptibility to acting on prepotent motor impulses compared to TD patients. This finding may have direct implications for fall risk and also points to dissociable neurocognitive pathologies in TD and PIGD subtypes. Clinically, the use of specific cognitive instruments to assess the expression and inhibition of motor impulses may help identify PD patients who have difficulty 'thinking before they leap' and are at high risk of falling.
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J. Neurol. Neurosurg. Psychiatr. · Dec 2012
ReviewLarge scale brain models of epilepsy: dynamics meets connectomics.
The brain is in a constant state of dynamic change, for example switching between cognitive and behavioural tasks, and between wakefulness and sleep. The brains of people with epilepsy have additional features to their dynamic repertoire, particularly the paroxysmal occurrence of seizures. Substantial effort over decades has produced a detailed description of many human epilepsies and of specific seizure types; in some instances there are known causes, sometimes highly specific such as single gene mutations, but the mechanisms of seizure onset and termination are not known. ⋯ These models are typically simplified, leaving a need to scale up these models to the large scale brain networks in which seizures become manifest. The emerging science of connectomics provides an approach to understanding the large scale brain networks in which normal and abnormal brain functions operate. The stage is now set to couple dynamics with connectomics, to reveal the abnormal dynamics of brain networks which allow seizures to occur.