History of neurology

The study of neurology dates back to prehistoric times, but the academic discipline did not begin until the 16th century. From an observational science it developed a systematic way of approaching the nervous system and possible interventions in neurological disease.

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Early history

The Edwin Smith papyrus contains careful descriptions of the injuries as well as the first descriptions of the cranial sutures, the meninges, the external surface of the brain, the cerebrospinal fluid, and the intracranial pulsations. There are many other examples of observations of neurological phenomena throughout history. The Sumerians illustrated paraplegia in a bas relief of a lion with an arrow in its back. The Egyptians described the effect of high transection of the spinal cord in humans. Hippocrates was convinced that epilepsy has a natural cause, not a sacred one. The Alexandrian Greeks dissected the human brain and distinguished the cerebrum from the cerebellum. Galen dissected the nervous system, in a variety of species, including the ape. Of recurrent laryngeal nerves he wrote: "If one cuts these nerves, the voice of the animal is damaged and its resonance is lost."

Anatomy and physiology

The development of modern neurology began in the sixteenth century with Vesalius, who described the anatomy of the brain and much else; he had little notion of function, thinking that it lay mainly in the ventricles. He did not remove the brain from the skull before cutting it. Thomas Willis in 1664, published his Anatomy of the Brain, followed by Cerebral Pathology in 1676. He removed the brain from the cranium, and was able to describe it more clearly, setting forth the circle of Willis – the circle of vessels that enables arterial supply of the brain. He had some notions as to brain function, including a vague idea as to localization and reflexes, and described epilepsy, apoplexy and paralysis. As already mentioned, he used the word neurology.

A beginning of the understanding of disease came with the first morbid anatomists, morbid anatomical illustration, and the development of effective colour printing. Matthew Bailie (1761-1823) and Jean Cruveilher (1791-1874) illustrated the lesions in stroke, in 1799 and 1829 respectively.

Microscopy

Only when cells were identified microscopically was it possible to progress beyond the crudest anatomical notion. J.E. Purkinje (1787-1869) in 1837 gave the first description of neurones, indeed a very early description of cells of any kind. Later Golgi and Cajal stained the ramifying branches of nerve cells; these could only touch, or synapse. The brain now had demonstrated form, without localised function. The famous philosopher René Descartes (1596-1650) speculated that every activity of an animal was a necessary reaction to some external stimulus; the connection between the stimulus and the response was made through a definite nervous path. Luigi Galvani (1737-1798) demonstrated that electrical stimulation of nerve produced muscle contraction, and the competing work of Charles Bell (1774-1842) and Francois Magendie (1783-1855 ) led to the view that the ventral horns of the spinal cord were motor and the dorsal horns sensory. A hemiplegic patient who could not speak led Paul Broca (1824-1880) to the view that functions in the cerebral cortex were anatomically localised. Ivan Pavlov (1849- 1936) realised as his dogs dribbled that a simple reflex could be modified by higher brain functions. These neurological ideas were coordinated and integrated by the neurophysiologist C.S. Sherrington (1857-1952).

Diagnostics

Doctors could use the ideas of neurology in practice only if they developed proper tools and procedures for clinical investigation. This happened step by step in the nineteenth century -- tendon hammer, ophthalmoscope, pin and tuning fork, syringe and lumbar puncture. X rays, the electro-encephalography, angiography, and CAT scans were to follow. The clinical neurologists correlated their findings after death with those of the neuropathologist. The best known was W.R. Gowers (1845-1915) who owned a major text in two volumes, of a cerebrospinal tract. By the end of the nineteenth century, the connection was established between stroke and hemiplegia, between trauma and paraplegia, between the spirochaete and the paralysed demency people who filled the mental hospitals. The first chemotherapeutic cure of a serious infection was salvarsan for syphilis, followed by the induction of fever in neurosyphilis. The treatment of neurosyphilis became highly effective when antibiotics were introduced.

Neurosurgery

In 1878, William McEwen (1848-1924) removed a meningioma, and the patient survived for many years. The first Englishman who did it was Victor Horsley (1857- 1916) five years later. The Americans did it even later, the surgeon was Harvey Cushing ( 1869-1939). Cushing in 1909 successfully removed a pituitary adenoma from an acromegalic. Treating endocrine hyperfunction by neurosurgery was a major neurological landmark. Modifying personality was the next thing to happen; many years before, a metal bar through the head of the railway worker Phineas Gage had demonstrated that mechanical disruption of the brain could alter personality. Egas Moniz (1874-1955) in Portugal developed neurosurgical treatment of severe psychiatric disorder.

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