Introduction

Although physicians commonly utilize screening instruments to identify cognitive problems and psychological issues in patients with various neurological etiologies, situations frequently arise when referral to a neuropsychologist is needed for a more comprehensive assessment.[1] Screening instruments, such as the Mini-Mental State Examination, are sensitive to moderate to severe cognitive impairment but relatively insensitive to milder forms of impairment; they are also susceptible to lower educational levels.[2] Health care professionals administering and interpreting screening measures of cognitive functioning should understand and employ the standardized administration procedures of the test, have knowledge of the development of the test, and use appropriate norms and procedures to interpret test scores. The reader should be aware that certain patient variables such as culture, language, and level of education may render certain tests inappropriate for some patients.

Clinical neuropsychologists are doctoral level health care providers who have specialized training in brain-behavior relationships and perform comprehensive evaluations in addition to providing certain forms of treatment. Therefore, cognitive screening tests can be useful to indicate the need for a consult with a neuropsychologist for further, more formal, and comprehensive examinations.[3]

Function

Neuropsychological evaluations require the use of standardized instruments to assess cognitive functions, behavior, social-emotional functioning (i.e., mood, personality), and in certain cases, adaptive functioning and academic achievement. More specifically, cognitive functions can be organized into specific major domains such as intelligence, attention/concentration, learning and memory, language, visuospatial and perceptual functions, executive functions, psychomotor speed, and sensory-motor functions. Given the complex nature of cognition, most standard test instruments measure more than one functional domain, though neuropsychologists have methods of differentiating strengths and weaknesses. Many neurologic and psychiatric disorders have been empirically shown to have specific patterns of dysfunction. Though more common with pediatric evaluation, adult evaluations may also require assessment of academic achievement skills in addition to cognitive and social-emotional functioning. The neuropsychological battery is typically chosen based on the referral question(s) and the suspected condition or conditions that need to be ruled out. An important part of neuropsychological evaluations is the use of Performance Validity Tests (PVTs) and Symptom Validity Tests (SVTs) in order to measure for the deleterious effects of suboptimal effort, to feign, and malingering, all of which can impact the outcome of exam results and interpretation. PVTs and SVTs are used in both pediatric and adult evaluations, even when there is no initial suspicion of possible exaggeration or concern for the fabrication of cognitive dysfunction.[4]

Comprehensive assessment typically begins with a detailed medical record review, including medical and psychiatric history, medications, laboratory results, and neuroimaging reports, and in-depth clinical interviews. The clinical interview includes behavioral observations and may last one to two hours. A wide variety of neuropsychological test instruments (primarily paper-pencil tests) are then administered; most are done sitting at a table in an outpatient clinic or private office or bedside in a hospital. Evaluations can vary from less than one hour to 6 to 8 or more hours of direct face-to-face examination, depending on the information sought and the patient’s stamina and motivation. In general, pediatric and more comprehensive adult evaluations are longer and are usually performed on an outpatient basis.

The neuropsychological evaluation is tailored to the needs of the individual patient. The neuropsychologist selects, administers, and interprets the particular battery of tests that will yield the most comprehensive understanding of an individual's strengths and weaknesses and help to answer the referral question(s). Following the explanation of the primary problem areas and diagnosis, the neuropsychologist then provides tailored recommendations for the patient. Test batteries can be either "flexible" or "fixed." Flexible test batteries are more common and may revolve around a core set of tests with additional tests employed, as needed to address specific issues. A flexible battery approach permits test selection on a case-by-case basis. However, some clinical neuropsychologists utilize a fixed battery approach, such as the Halstead-Reitan Battery (HRB) or the Luria-Nebraska Neuropsychological Battery (LNNB), although this is less common.[5] 

Tests are administered in a standardized manner (meaning each test is administered according to the methods outlined in the respective test manuals for every patient), and scores are interpreted by comparing the patient’s scores to an appropriate normative group. Depending on the test, norms should be selected to match the patient's gender, age, education, and ethnicity. The reader should note that neuropsychological evaluations are thorough examinations with multiple components and involve much more than the administration of a few tests. A neuropsychological evaluation is not limited to testing but also involves, as mentioned above, a clinical interview, review of medical records, testing current cognitive and academic abilities, tests of social-emotional functioning and personality, adaptive functioning, estimates of premorbid functioning, behavioral observations, and integration of all these components. In addition, the clinician may also need to obtain educational and employment records and conduct collateral interviews with family members.[6]

Issues of Concern

Neuropsychological assessment is performed for several reasons. The following are a few of the goals and benefits:

• To establish a “baseline” if later changes are anticipated (e.g., pre- and post-surgery) or to help determine if a patient is a good candidate for surgical intervention.

• To gauge an individual’s cognitive and emotional profile (i.e., strengths and weaknesses) and aid in treatment planning.

• Differential diagnosis, when brain-based impairment in cognitive function or behavior is suspected (e.g., memory complaints).

• To establish possible lateralization or etiology of brain lesion.

• To track progress in rehabilitation and the effects of treatment and medication.

• To help with educational placement, interventions, and accommodations.

• For determination of disability, return-to-work/school, driving ability, or forensic (legal) purposes.[7]

Clinical Significance

Patients with brain injury can benefit from neuropsychological assessment as part of an interprofessional team approach to care. As mentioned above, cognitive assessment can help dictate a treatment plan, monitor recovery, and help determine when a person is ready to return to work, driving, or sports.[8]

Another clinical population for which assessment is valuable is older patients with long-standing memory concerns along with other cognitive deficits with or without corresponding brain atrophy. These cases may require an assessment to help determine a differential diagnosis as well as aid in decision-making. Other groups with reported memory and other cognitive problems also may require dementia assessment and consideration of psychological factors contributing to a patient’s symptoms (e.g., dementia versus depression).[9]

Psychological factors can be overlooked in neurological patients. These may include mood changes such as depression or anxiety, including post-traumatic stress disorder, or behavioral dysfunction such as agitation, poor initiation, or wandering. Emotional and behavioral sequelae can be the direct result of underlying neurological impairment. For example, patients with left frontal strokes or those localized to subcortical areas of the brain can experience an “organic depression.” Alternatively, damage to frontal areas also may result in behavioral disturbances such as disinhibition, impulsivity, abulia, and emotional lability. A comprehensive neuropsychological assessment, in this case, would also assess for neuropsychiatric sequelae.[10]

Forensic issues, such as that of capacity (competency, in legal terms), also can arise in medical settings. Decision-making capacity, whether for a medical procedure, designation of a health care agent, or disposition, is a clinical finding regarding a patient’s decisional abilities. Although people are presumed to have the capacity, cognitive impairment and/or psychiatric disturbances can impair one’s capacity to make decisions. Neuropsychologists often are called in to help assess capacity; this always involves an interview with the patient and any collaterals, as well as an assessment of functional abilities. A full neuropsychological assessment is not always required, although some evaluation of cognition usually is performed.[11]

Many other patients with neurological and/or psychiatric etiologies can benefit from a neuropsychological assessment. In children, neuropsychologists often work with the school system to provide accommodations for deficits.[12]

Other Issues

Sensory deficits such as poor visual acuity or visual field cut, or hearing impairment and motor deficits (e.g., ataxia) need to be taken into consideration when assessing any of the above populations, as tests require visual and verbal input and sometimes writing or manual manipulation of stimuli. 

Another issue is that of cross-cultural competence. Although beyond the scope of this article, neuropsychologists must ensure that patients have fluency with the language they are being tested. For example, if the language of test administration is English, and the patient's native language is Chinese Mandarin, a high level of English fluency is required by the patient in order to consider completing the evaluation in English. Even so, fluency in the language of testing does not necessarily eliminate the need for the patient to receive a bilingual evaluation in both their native and second languages. In cases where the patient is not fluent in the target language, it is highly advisable to refer the patient to a bilingual neuropsychologist who speaks both languages fluently and has experience working with bilingual individuals.  The use of interpreters and/or technicians who are bilingual may also be necessary in order to obtain valid test results and appropriately communicate with the patient during the duration of the evaluation and when providing feedback of results.[13]

Enhancing Healthcare Team Outcomes

Health professionals may not always be aware when a referral to a neuropsychologist is needed. Neuropsychologists have specialized training in brain-behavior relationships and perform comprehensive cognitive evaluations in addition to providing treatment. Cognitive screening can be useful to indicate the need for a consult for further, more formal testing. Primary care providers, neurologists, and nurses should be involved in referrals. The interprofessional team should be aware of this option to provide the best outcomes for patients.