Comprehensive guide to evaluate cognitive function

Abstract

Dementia is an acquired cognitive decline in one or more cognitive domains including memory, attention, executive function, learning, language, perception, and social cognition. They interfere significantly with a person's everyday independence in dementia, but not so in mild cognitive impairment (MCI). Evidence of significant cognitive decline from a previous level of performance can be noted by a concern of the individual, knowledgeable informant such as family member, or the clinician. A substantial impairment in cognitive performance, however, may be documented by standardized neuropsychological testing.

Neurophysiological testing is essential to determine incremental improvements or declines in cognitive functioning and to speculate the involved brain regions. Results of the testing can indicate cognitive functioning of a patients, help diagnosing the cause of dementia, and evaluate the effect of therapeutic intervention. The MMSE, HDS–R, and MoCA are brief comprehensive testing used extensively in clinical settings to screen for dementia. ADAS–cog also is a testing to measure cognition, but more thorough than the MMSE, in research studies and clinical trials for new drugs.

Several tests are available to evaluate specific cognitive domains of interest. The frontal assessment battery is a brief testing of six neuropsychological tasks designed to assess frontal lobe function. The Kohs Block Design Test is a non–verbal assessment of executive functioning, useful with the language and hearing impaired. The Rivermead Behavioral Memory Test includes 14 subtests assessing aspects of visual, verbal, recall, recognition, immediate and delayed everyday memory. The Clinical Dementia Rating or CDR is a numeric scale used to quantify the severity of cognitive decline, beneficial for the early diagnosis of dementia and staging. Neuropsychiatric Inventory (NPI) was developed to provide a brief assessment of neuropsychiatric symptomatology in routine clinical practice settings. The NPI includes 12 neuropsychiatric domains and evaluate its frequency, severity, and the severity of caregiver distress of each behavior. Appropriate testing should be selected depending on its purpose, and mental and physical condition of a patient.