Neurology

Neurology is a branch of medicine dealing with the nervous system and its disorders. Physicians specializing in the field of neurology are called neurologists. Surgery on the nervous system is performed by physicians with specialized training - neurosurgeons, and, in some cases, interventional neuroradiologists.

Field of work
Neurological disorders are disorders that affect the central nervous system (brain, brainstem and cerebellum), the peripheral nervous system (peripheral nerves - cranial nerves) included), or the autonomic nervous system (parts of which are located in both central and peripheral nervous system).

Major conditions include:
 * headache disorders such as migraine and tension headache (cluster headache)
 * epilepsy and seizure disorders
 * neurodegenerative disorders, the most common class being dementias, including Alzheimer's disease
 * cerebrovascular disease, such as transient ischemic attacks, and strokes (ischemic or hemorrhagic)
 * sleep disorders
 * cerebral palsy
 * bacterial, fungal, viral and parasitic infections of the central nervous system (encephalitis), brain envelopes (meningitis) and peripheral nerves (neuritis), such as brain abscess, herpetic meningoencephalitis, aspergilloma, cerebral hydatic cyst, tetanus, botulism
 * neoplasms - tumors of the brain and its envelopes (brain tumors), spinal cord tumors, tumors of the peripheral nerves (neuroma)
 * movement disorders such as Parkinson's disease, chorea, hemiballismus, tic disorder, and Gilles de la Tourette syndrome
 * demyelinating diseases of the central nervous system, such as multiple sclerosis, and of the peripheral nervous system, such as Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy (CIDP)
 * spinal cord disorders - tumors, infections, trauma, malformations (e.g., myelocele, meningomyelocele, tethered cord)
 * disorders of peripheral nerves, muscle and neuromuscular junctions
 * traumatic injuries to the brain, spinal cord and peripheral nerves
 * Altered mental status, encephalopathy, stupor and coma

General caseload
Neurologists are responsible for diagnosing and treating all of the above conditions, except for surgical interventions, which fall into the responsibility of neurosurgeons, and in some cases interventional neuroradiologists. In some countries, additional legal responsibilities of a neurologist include making a finding of brain death when it is suspected that a patient is deceased, and filing the necessary paperwork for issuance of a death certificate. Neurologists are also called on to certify brain death in the cases of organ donors. Neurologists frequently care for people with hereditary (genetic) disease when the major manifestations are neurologic, as is frequently the case.

Neurologists may specialize in clinical neurophysiology, the field responsible for electroencephalography (EEG), nerve conduction studies (NCS) and electromyography (EMG). The interpretation of such evoked potentials such as somatosensory evoked potentials (SSEP), visual evoked potentials (VEP) and brainstem auditory evoked response (BAER) also falls under the domain of neurophysiology. Other neurologists may develop an interest in particular subfields, such as the movement disorders, headaches, epilepsy or neuromuscular disease.

Diagnostic lumbar punctures are frequently performed by neurologists.

Overlap with psychiatry
Although many mental illnesses are believed to be neurological disorders affecting the central nervous system, traditionally they are classified separately, and treated by psychiatrists. In a 2002 review article in the American Journal of Psychiatry, Professor Joseph B. Martin, Dean of Harvard Medical School and a neurologist by training, wrote that 'the separation of the two categories is arbitrary, often influenced by beliefs rather than proven scientific observations. And the fact that the brain and mind are one makes the separation artificial anyway.' (Martin JB. The integration of neurology, psychiatry and neuroscience in the 21st century. Am J Psychiatry 2002; 159:695-704)

There are strong indications that neuro-chemical mechanisms play an important role in the development of, for instance, bipolar disorder and schizophrenia. As well, 'neurological' diseases often have 'psychiatric' manifestations, such as post-stroke depression, depression and dementia associated with Parkinson's disease, mood and cognitive dysfunctions in Alzheimer's disease, to name a few. Hence, there is no sharp distinction between neurology and psychiatry on a biological basis - this distinction has mainly practical reasons and strong historical roots (such as the dominance of Freud's psychoanalytic theory in psychiatric thinking in the first three quarters of the 20th century - which has since then been largely replaced by the focus on neurosciences - aided by the tremendous advances in genetics and neuroimaging recently.)