Lesson 4 - Assessment and the DSM-V

Neuropsychological Tests

In addition to a general medical examination, specialized neurological tests may be performed on patients. This type of testing is done because some mental disorders are directly linked to brain pathology. Clinicians use both neurological test batteries (a battery is a grouping of specific tests) and brain scans to assist in describing the brain-behaviour relationship. Two of the main neuropsychological batteries are the Luria-Nebraska and the Halstead-Reitan. These tests are administered in an attempt to locate and identify brain damage. Despite the occurrence of false-positives (test results that indicate brain damage where there is none) and false-negatives (test results that indicate no brain damage where there is some), the Halstead-Reitan is a reasonably reliable tool.

As noted previously, neuropsychological tests are used in conjunction with brain imaging tests to help determine areas of brain damage. These imaging tests include computerized axial tomography (known as CAT scans or CT scans), magnetic resonance imaging (MRI scans), electroencephalograms (EEGs), and positron emission tomography (PET scans). CT scans use x-rays; a narrow x-ray beam is passed through a person’s head and the amount of radiation absorbed is measured. The images produced show the brain in three different dimensions. From these images, structural abnormalities (injury and/or tumors) can be identified.

EEGs are used to assess general brain-wave patterns. They are obtained by placing electrodes on the scalp and recording brain-wave impulses. The pattern of these impulses can indirectly reveal abnormal brain-wave patterns and brain abnormalities such as brain lesions. PET scans, on the other hand, measure metabolic activity. In this scan, a harmless radioactive isotope is passed into the brain. This allows the clinician to see which areas of the brain are the most active. For example, they help pinpoint sites responsible for epileptic seizures. Using very large magnets, MRIs provide detailed pictures of the brain at any angle. An MRI can examine structure and function simultaneously. People with any metal in their bodies, however, cannot be scanned using this equipment because the metal would be pulled out of their body by the magnet! Refer to the chart below to see summary of tests.

Chart of Tests