TRAUMATIC BRAIN INJURY

ion The Oxford English Dictionary notes that the term “abstraction” came into the English language in 1647� It is defined as the act of processing separately in thought, or considering a thing independently of its associations, or acknowledging a substance independent of its attributes, or separating an attribute or quality independent of the substance to which it belongs (Simpson and Weiner 1989)� In other words, the ability to abstract is the mental act of interpreting observations and associations beyond their apparent or literal meaning� The lack of ability of abstract thought is termed “concrete thinking�” Persons with executive function impairment, particularly frontal lobe disease, often lose the ability to think abstractly� The common test taught to all psychiatric residents is that of interpretation of proverbs or being able to draw a similarity between terms or words (similarities)� The classic forms of asking the patient to interpret “A rolling stone gathers no moss,” is known to all psychiatric residents� Obviously, the clinician can increase the complexity of proverb interpretation by ultimately asking the patient to interpret “He who chooses to eat with the tiger must remember that the tiger eats last�” The FAB asks the patient to determine in what way a banana and an orange are alike� If the patient fails the question, she is asked “What makes a table and a chair alike?” In the alternative, she is asked “What makes a tulip, a rose, and a daisy alike?” (Dubois et al� 2000)� Clearly, one must take into account the culture, language, educational level, and socioeconomic background of the person when interpreting their ability to abstract correctly� Table 4�14 lists common signs and symptoms of dysexecutive disorders� SENSORY DOMAIN-SPECIFIC RECOGNITION This domain of mental status testing is used to determine the presence of agnosia (a lack of knowing)� Agnosia may present as impairment in any of the five senses and may occur in myriad diseases� Therefore, for proper assessment, elementary sensory function has to be present in the patient, and the clinician must ensure that there is no presence of blindness, deafness, inability to smell, a dense hemisensory loss, or peripheral neuropathy� Agnosia is sensory domain-specific, and, therefore, the stimulus used must be specific to the sense in which agnosia is identified� If visual agnosia is considered in the patient, a simple test can be performed to have the individual sit across from the clinician, place her palms face up on her TABLE 4.14 Signs and Symptoms of Executive Dysfunction • Outrageous and disinhibited behavior • Impulsiveness or perseveration of oral or written information • Reduced ability to express words • Poor visual or auditory attention • Reduction in motivation or drive • Inability to switch sets or inhibit responses • Inability to plan for the future • Inability to organize 150 Traumatic Brain Injury: Methods for Clinical and Forensic Neuropsychiatric Assessment knees, and close her eyes� The clinician then places a common object, such as a key, in the palm and then instructs the patient to feel the object with eyes closed and name it� If she cannot do so, the clinician asks her to open her eyes and look at the object and to demonstrate how it is used� This will test for recognition and appropriate use of the object� It should be remembered that a person may have visual agnosia and yet be able to name an object when it is presented tactily or auditorily� If she cannot identify the object by active touching, despite her inability to recognize it visually, she is described as having astereognosia� If the patient cannot name the object regardless of the sensory domain in which it is presented, this finding is consistent with anomia, and other elements of impaired language function should be sought� As will be discussed further in Chapter 6, sensory motor elements of the Halstead–Reitan Battery can be used to examine for astereognosia, agraphesthesia (inability to recognize letters and numbers drawn on the fingertip or hand), or other tactile recognition failures� As another example in the auditory domain, pure word deafness is an inability to recognize words when spoken, despite the patient’s ability to read them� Simultanagnosia is the inability to recognize the Gestalt or wholeness of an image or picture, despite being able to recognize parts of the image or picture� Finger agnosia is the inability to recognize one’s fingers on the hand and often presents as a component of the Gerstmann syndrome� Olfactory agnosia (parosmia) is the inability to recognize odors, even though nerve I is intact�