A
neurological examination can, to some extent, assess the impact of neurological damage and disease on brain function in terms of
behavior,
memory, or
cognition.
Behavioral neurology specializes in this area. In addition,
clinical neuropsychology uses
neuropsychological assessment to precisely identify and track problems in mental functioning, usually after some sort of brain injury or neurological impairment. Alternatively, a condition might first be detected through the presence of abnormalities in mental functioning, and further assessment may indicate an underlying neurological disorder. There are sometimes unclear boundaries in the distinction between disorders treated within neurology, and
mental disorders treated within the other medical specialty of
psychiatry, or other
mental health professions such as
clinical psychology. In practice, cases may present as one type, but be assessed as more appropriate to the other.
Neuropsychiatry deals with
mental disorders arising from specific identified diseases of the nervous system. One area that can be contested is in cases of
idiopathic neurological symptoms - conditions where the cause cannot be established. It can be decided in some cases, perhaps by
exclusion of any accepted diagnosis, that higher-level brain/mental activity is causing symptoms, referred to as
functional symptoms, rather than the symptoms originating in the area of the nervous system from which they may appear to originate. Cases involving these symptoms are classified as
functional disorders ("functional" in this context is usually contrasted with the old term "
organic disease"). For example, in
functional neurologic disorder (FND), those affected present with various neurological symptoms such as
functional seizures,
numbness,
paresthesia, and
weakness, among others. Such cases may be contentiously interpreted as being "psychological" rather than "neurological." If the onset functional symptoms appear to be causally linked to emotional states or responses to social
stress or social contexts, it may be referred to as
conversion disorder. On the other hand,
dissociation refers to partial or complete disruption of the integration of a person's conscious functioning, such that a person may feel detached from one's emotions, body and/or immediate surroundings. In extreme cases, this may be diagnosed as
depersonalization-derealization disorder. There are also conditions viewed as neurological where a person appears to consciously register neurological stimuli that cannot possibly be coming from the part of the nervous system to which they would normally be attributed, such as
phantom pain or
synesthesia, or where limbs act without conscious direction, as in
alien hand syndrome. Conditions that are classed as
mental disorders,
learning disabilities, and forms of
intellectual disability, are not themselves usually dealt with as neurological disorders.
Biological psychiatry seeks to understand mental disorders in terms of their basis in the nervous system, however. In clinical practice, mental disorders are usually indicated by a
mental state examination, or other type of structured interview or questionnaire process. At the present time,
neuroimaging (brain scans) alone cannot accurately diagnose a mental disorder or tell the risk of developing one; however, it can be used to rule out other medical conditions such as a
brain tumor. In research, neuroimaging and other neurological tests can show correlations between reported and observed mental difficulties and certain aspects of neural function or differences in brain structure. In general, numerous fields intersect to try to understand the basic processes involved in mental functioning, many of which are brought together in
cognitive science. The distinction between neurological and mental disorders can be a matter of some debate, either in regard to specific facts about the cause of a condition or in regard to the general understanding of brain and
mind. ==See also==