I have had a longstanding interest in the detection and prevention of brain damage in acutely sick children. Whilst at Guys Hospital, I initiated a research project on the management of the unconscious child, looking particularly at the prediction of outcome and the prevention of secondary deterioration. From this, I became interested in cerebral ischaemia and in methods of deciding whether or not cerebral blood flow was adequate. After an exhaustive literature review of the latter topic, I realised that the then newly described technique of transcranial Doppler ultrasound was the most promising methodology and I initiated a collaboration with Dr Soundrie Padayachee and Professor Ray Gosling in work validating the technique. I went on to obtain grants from the British Heart Foundation to study initially the monitoring of cerebral perfusion and function in the unconscious child (1983-6) and, after my arrival at the Institute of Child Health, to study methods of ensuring adequate cerebral perfusion during cardiopulmonary bypass (1991-7). Having spent some time in Professor Simon Shorvons Unit, I became interested in the role of seizures and status epilepticus in causing secondary deterioration after acute insults and continue to publish in this area in papers, abstracts and chapters. The development of techniques for imaging and monitoring cerebral perfusion and for documenting seizures have allowed insights into the pathogenesis of secondary deterioration after brain insults and should lead to the development of collaborative controlled trials, such as that randomising children with head injury to surgical decompression or medical management (SUDEN RCT: Mr Patrick Mitchell in Newcastle; Dr Peter Wilson and myself in Southampton). More recently, I have developed an interest in focal brain ischaemia in children, and in particular its early diagnosis using magnetic resonance techniques, including spectroscopy, diffusion and perfusion and voxel-based morphometry.