Determination of mental competency, a neurological perspective.

This article discusses the evaluation of the capacity of a person to make informed decisions about financial matters, independent living, and informed consent for medical treatment and research. Determination of capacity is a function for which most physicians have little training. The determination of competency for a general medical patient may be assessed by a combination of a bedside mental status examination such as the MMSE and a questionnaire such as the Aid To Capacity Evaluation (ACE 1999). For patients with focal neurological deficits such as aphasia, further evaluation of specific cognitive and language functions is needed; Alexander (Arch Neurol 45:23-6, 1988) suggested 7 specific functions to be assessed. Finally, in dementing illnesses, evaluation by the MMSE and a questionnaire such as the CCTI, or Capacity to Consent to Treatment Instrument (Marson et al. Arch Neurol 52:949-54, 1995) is needed. Dementia includes several separate syndromes of neurodegenerative disease, and in many of these conditions, focal deficits such as aphasia may necessitate a more thorough neuropsychological evaluation.