Neuropsychological evaluation is an assessment of how one's brain functions, which indirectly yields information about the structural and functional integrity of your brain. The neuropsychological evaluation involves an interview and the administration of tests. The tests are typically pencil and paper type tests. Some tasks might be self-reports meaning that they are completed by the patient with assistance from a technician, but the majority of the tests require administration by a neuropsychologist or trained, skilled psychometrist.

Neuropsychological tests (unlike bedside cognitive and behavioral neurologic screens) are standardized, meaning that they are given in the same manner to all patients and scored in a similar manner time after time. An individual's scores on tests are interpreted by comparing their score to that of healthy individuals of a similar demographic background (i.e., of similar age, education, gender, and/or ethnic background) and to expected levels of functioning. In this way, a neuropsychologist can determine whether one's performance on any given task represents a strength or weakness. Although individual scores are important, the neuropsychologist looks at all of the data from the evaluation to determine a pattern of cognitive strengths and weaknesses and, in turn, to understand more about how the brain is functioning.

Neuropsychological tests evaluate functioning in a number of areas including: intelligence, executive functions (such as planning, abstraction, conceptualization), attention, memory, language, perception, sensorimotor functions, motivation, mood state and emotion, quality of life, and personality styles. The areas addressed in an individual's evaluation are determined by the referral question (what the referring doctor and patient wants to know), patient's complaints and symptoms, and observations made during interview and test administration.

A complete evaluation generally takes between two and five hours to complete, but can take up to eight hours, depending on the complexity of the issues to be addressed by the evaluation and the patient's condition (for example, fatigue, confusion, and motor slowing can extend the time required for an evaluation). Occasionally, it is necessary to complete the evaluation over two or more sessions. In general, the clinician attempts to elicit the patient's best possible performance under optimal conditions.

Neuropsychological evaluation documents patterns of strengths and weakness among cognitive and behavioral functions. For patients with Parkinson's disease or another movement disorder, an evaluation and interpretation of this pattern of strengths and weaknesses can:

• Assist in a differential diagnosis (e.g., to determine whether possible mental and behavioral changes are related to the movement disorder, depression, another brain disease or treatment);
• Assist with evaluation before and after functional neurosurgical procedures (e.g., deep brain stimulation) to help determine if a given treatment is appropriate for a particular person and whether treatment has had any positive or negative effects on mental functions and behavior;
• Provide a baseline against which subsequent evaluations can be compared. Thereby your doctors can decide whether your functioning has declined because of the disease process or document whether your functioning has worsened or improved as a result of treatment (e.g. medications or DBS);
• Reveal areas of daily functioning (e.g., financial management) with which the patient may need assistance indicate rehabilitation potential. For example, will the individual benefit from certain cognitive or behavioral treatments, occupational therapy, or pharmacotherapy?

These are not tests that one can study for, but there are several things that one can do to facilitate the evaluation:

• The patient should bring a current list of ALL medications and doses (because medicines may change frequently for some persons, it is important to make sure the list is up to date)
• If the patient has difficulty providing information about their history, it is helpful for a family member or friend to accompany them (for at least part of the clinical interview).
• It is helpful if the patient can provide records of previous neurodiagnostic testing (e.g., brain scans such as CT or MRI scans) and/or results from previous neuropsychological evaluations if completed at another hospital or institution.

It is the goal of the neuropsychologist to get the best possible picture of the patient's current functioning. Several things can interfere with this goal, for instance if the patient is:

• Excessively tired or fatigued or has sudden, unexpected "sleep attacks:"
• Not motivated to put forth their best effort;
• Very emotionally distraught or has a severe psychiatric condition;
• Under the influence of medications or illicit substances which interfere with cognitive functioning;
• Experiencing frequent changes in the ability to move.

Patients should let the examiner know if they anticipate that any of these issues are likely to interfere with the evaluation.

It is important to get a good night's rest before evaluation. Patient's who live far away might consider spending the evening prior to the evaluation at a local hotel or with friends/family rather than getting up and driving/flying most of the night to get to the appointment. Patients are encouraged not to consume any alcohol 24 hours prior to the evaluation. If taking sleep medicine, patients should check with their doctor whether it might affect test performance the next day

Patients should not worry about whether they will "pass" the tests. The tests cannot be passed or failed; instead they describe how well person performs relative to peers.