Chapter 14 - Neuropsychological Assessment

• The branch of medicine that focuses on the nervous system and its disorders is neurology. 
• The branch of psychology that focuses on the relationship between brain functioning and behavior is neuropsychology.
• Neuropsychological assessment may be defined as the evaluation of brain and nervous system functioning as it relates to behavior. Subspecialty areas within neuropsychology include pediatric neuropsychology, geriatric neuropsychology, forensic neuropsychology, and school neuropsychology.
• A subspecialty within the medical specialty of neurology that also focuses on brain–behavior relationships (with more biochemical and less behavioral emphasis) is behavioral neurology. There are even subspecialty areas within behavioral neurology. 
• For example, neurotology is a branch of medicine that focuses on problems related to hearing, balance, and facial nerves.
• The nervous system is composed of various kinds of neurons (nerve cells) and can be divided into the central nervous system (consisting of the brain and the spinal cord) and the peripheral nervous system (consisting of the neurons that convey messages to and from the rest of the body). Viewed from the top, the large, rounded portion of the brain (called the cerebrum) can be divided into two sections, or hemispheres.
• Each of the two cerebral hemispheres receives sensory information from the opposite side of the body and also controls motor responses on the opposite side of the body—a phenomenon termed contralateral control.
• Neurological damage may take the form of a lesion in the brain or any other site within the central or peripheral nervous system. 
• A lesion is a pathological alteration of tissue, such as that which could result from injury or infection. Neurological lesions may be physical or chemical in nature, and they are characterized as focal (relatively circumscribed at one site) or diffuse (scattered at various sites).
• The term brain damage is a general reference to any physical or functional impairment in the central nervous system that results in sensory, motor, cognitive, emotional, or related deficit. 
• Accordingly, Goldstein and his colleagues developed psychological tests that tapped these factors and were designed to help in the diagnosis of organic brain syndrome, or organicity for short. In general, the tests included tasks designed to evaluate testtakers’ short-term memory and ability to abstract.
• A hard sign may be defined as an indicator of definite neurological deficit. Abnormal reflex performance is an example of a hard sign. Cranial nerve damage as indicated by neuroimaging is another example of a hard sign. 
• A soft sign is an indicator that is merely suggestive of neurological deficit. Soft signs include test scores that are more likely to be obtained by people with brain injuries than by people without brain injuries.
• The presence or absence of certain developmental milestones, a particularly critical part of the history-taking process when examining young children.
• Such psychologists feel confident in performing many of the same noninvasive procedures (procedures that do not involve any intrusion into the examinee’s body) that neurologists perform as part of their neurological examination. In the course of the following discussion, we list some of these noninvasive procedures.
• Reflexes are involuntary motor responses to stimuli. Many reflexes have survival value for infants but then disappear as the child grows older.
• Parkinson’s disease (PD) is a progressive, neurological illness that may also have several nonmotor symptoms associated with it (ranging from depression to dementia).
• We now know that PD results from cell loss in a specific area of the brain called the substantia nigra (from the Latin for “black substance” because the region appears black under a microscope). 
• The neurons in the substantia nigra are responsible for producing dopamine, a neurotransmitter (or, a chemical facilitator of communication between neurons) essential for normal movement. 
• Other varieties of Parkinson’s are known to be caused by certain prescription medicines and nonprescription street drugs (such as contaminated heroin). However, the vast majority of diagnoses of PD are characterized in medical jargon as idiopathic (of unknown origin).
• There may also be issues with swallowing and excessive salivation. Another of the many varied potential consequences of PD is rapid eye movement sleep behavior disorder which is a condition characterized by an “acting out” of dreams with vocalizations or gestures. A wide variety of symptoms that are not properly neuromuscular in nature may also be evident in patients with PD. 
• Unfortunately, many of the medications available for the treatment of PD come with their own “baggage” in terms of potential side effects. For example, dyskinesias (involuntary, jerking-type movements) may result from the long-term use of some of these medications.
• First described by Frederick H. Lewy in the early 1900s, what are now known as Lewy bodies are clusters of stuck-together proteins that have the effect of depleting available dopamine and other brain substances (such as acetylcholine) critical for normal functioning. 
• DBS is a neurosurgical treatment for use with patients who have advanced PD. The procedure entails the surgical implantation of electrodes at specific sites in the brain. 
• Lewy body dementia results from the formation of a number of Lewy bodies in the brain stem and cerebral cortex that cause Parkinsonian-like symptoms, Alzheimer-like symptoms, and other symptoms of dementia. 
• In some cases, the neurologist may order additional tests, such as one called a DaTscan (pronounced in a way that rhymes with “cat scan”). A DaTscan entails the use of high-tech imaging equipment to visualize the substantia nigra and gauge the amount of dopamine present. 
• Because certain patterns of test response indicate particular deficits, the examiner looks beyond performance on individual tests to a study of the pattern of test scores, a process termed pattern analysis. 
• A number of researchers intent on developing a definitive sign of brain damage have devised various ratios and quotients based on patterns of subtest scores. David Wechsler himself referred to one such pattern, called a deterioration quotient or DQ (also referred to by some as a deterioration index). 
• Sorting tests measure one element of executive function, which may be defined as organizing, planning, cognitive flexibility, and inhibition of impulses and related activities associated with the frontal and prefrontal lobes of the brain.
• A test used to quickly screen for certain executive functions is the clock-drawing test (CDT). As its name implies, the task in this test is for the patient to draw the face of a clock, usually with the hands of the clock indicating a particular time (such as “ten minutes after eleven”). 
• The testtaker’s task on the Boston (as it is often abbreviated) is confrontation naming; that is, naming each stimulus presented.
• The term perceptual test is a general reference to any of many instruments and procedures used to evaluate varied aspects of sensory functioning, including aspects of sight, hearing, smell, touch, taste, and balance. 
• Similarly, motor test is a general reference to any of many instruments and procedures used to evaluate varied aspects of one’s ability and mobility, including the ability to move limbs, eyes, or other parts of the body. 
• The term perceptual motor test is a general reference to any of many instruments and procedures used to evaluate the integration or coordination of perceptual and motor abilities.
• Once widely used neuropsychological test is the Bender Visual-Motor Gestalt Test, usually referred to simply as the Bender-Gestalt or even just “the Bender.” 
• Not to be confused with aphagia, aphasia refers to a loss of ability to express oneself or to understand spoken or written language because of some neurological deficit.2 A number of tests have been developed to measure aspects of aphasia.
• Procedural memory is memory for things like driving a car, making entries on a keyboard, or riding a bicycle. Most of us can draw on procedural memory with little effort and concentration. 
• Declarative memory refers to memory of factual material—such as the differences between procedural and declarative memory
• Semantic memory is, strictly speaking, memory for facts.
• Episodic memory is memory for facts in a particular context or situation.