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Research Portfolio


New insights into photosensitive epilepsy and seizure activity


Grant round winners 2010

grant amount:

£99,980 over 24 months

lead investigator:

Dr Khalid Hamandi



University Hospital of Wales


Approximately five percent of people with epilepsy have photosensitive epilepsy, where flashing lights or other visual stimuli can trigger seizures. The precise mechanism for photosensitive epilepsy is unclear, but it appears to be linked to groups of nerve cells or neurons firing abnormally at the same time. This is known as synchronisation. Abnormal synchronisation plays an important role in all epileptic seizures, and can be seen as clinically as a disturbance in neural oscillation. Neural oscillation refers to the rhythmic or repetitive activity of neurons, and is driven by complex interactions between groups of neurons.

Electrical currents produce a magnetic field, and the electrical currents in neurons are no different. Magnetoencephalography (MEG) is a technique that can measure tiny variations in magnetic field at the scalp surface, caused by underlying neural activity. It is comparable to the way in which the standard electroencephalogram (EEG), measures alterations in electrical changes at the scalp surface. One advantage of MEG, however, is that it is better at measuring neuronal oscillations and pinpointing their locations within the brain. In addition it is non-invasive (i.e. it doesn’t involve radiation, needles or surgical procedures) and is completely passive; the scanner simply records activity. MEG can be used to compare the brain oscillation measurements of people with epilepsy with those of healthy controls, both at rest and whilst performing certain activities in the scanner.

Dr Khalid Hamandi from University Hospital of Wales and colleagues Professor Krishna Singh and Dr Suresh Muthukumaraswamy from Cardiff University, have been awarded £99,980 over 24 months, to carry out a project entitled Magnetoencephalographic measures of abnormal sensory oscillations: a window on photosensitive epilepsy. Using MEG the group will measure brain responses to a variety of low-level visual stimuli (ones that don’t usually cause seizures) in people who have photosensitive epilepsy or non-photosensitive epilepsy, and compare these measurements with healthy controls.

The team hopes that this research will not only increase our understanding of photosensitive epilepsy, but also unravel new aspects of neuronal function that lead to abnormal synchronization. This knowledge will potentially lead to more targeted treatments and more effective epilepsy diagnosis techniques in the future.

The Study