Neurological disorders range from acute emergencies such as stroke and meningitis to long-term conditions like multiple sclerosis (MS) and Parkinson’s disease. Clinical neurophysiologists assess nervous system function, and diagnose and monitor neurological disorders using electrical, magnetic and computerised techniques such as electroencephalography (EEG), electromyography (EMG), nerve conduction studies (NCS) and evoked potentials (EPs). This distinguishes them from the neurologists who go on to treat these patients.

It was the harnessing of electricity that made clinical neurophysiology possible. Alexander Hughes Bennett (1848–1901) was particularly interested in the use of electricity in diagnosing diseases of the nervous system. An article in the British Medical Journal in 1880 on the subject was followed in 1882 by a full-length book.

Bennett notes that, for most of medical history, accurate diagnosis had been ‘in the highest degree unsatisfactory’, owing to the vagueness of the observations that could be made. He notes that diseases of the nervous system had so far ‘baffled’ attempts made using new technologies such as the stethoscope, ophthalmoscope, laryngoscope, microscope and thermometer. The electrical techniques described in the book enable the physician ‘accurately to determine the anatomical conditions of nerve and muscle’. Though a full understanding of the uses of electricity in this field was still lacking, he believed that 'there are already enough facts to indicate the great practical importance of the subject, and to point to a vast field of research, which will doubtless lead to future profit'.

Anthony Martin Halliday (1926–2008) was a consultant in clinical neurophysiology to the National Hospital for Nervous Diseases, London (now the National Hospital for Neurology and Neurosurgery). His greatest scientific contribution was his pioneering work on pattern-reversal visual evoked potentials (EPs with a visual stimulus) and its clinical applications. Together with William Ian McDonald (1933–2006) he developed the technique which opened an entirely new field in clinical neurology and was rapidly adopted as one of the most important laboratory tests for the diagnosis of MS.

Halliday’s laboratory became a magnet for young neurophysiologists and many returned to their own countries after working with him to build up outstanding careers in the discipline. He published over 200 scientific papers and many of his discoveries and those of his students were written up in his book Evoked potentials in clinical testing (Edinburgh: Churchill Livingstone, 1982) and its second edition published in 1993. An early member and sometime president of the EEG Society, now the British Society for Clinical Neurophysiology, he was awarded their Grey Walter medal in 1989.

Karen Reid, library manager

Clinical neurophysiology is the RCP specialty spotlight for July 2016.