The sailor who won’t follow orders
Mr. L is rehospitalized 9 times in 3 months but repeatedly fails to adhere to outpatient treatment. What is the cause of his exasperating behavior?
These results suggest Mr. L has difficulty with attention and working memory, short-term memory, fund of general information and long-term memory, and ability to perform simple calculations. Most important, they indicate the need for further study, especially a neuropsychological test battery.
Mr. L’s abnormal neuropsychological test results are summarized in the Table. He manifests concretization of thought. His loss of conceptual fluidity is documented formally by measures of perseverative errors and categories completed on the Wisconsin Card Sorting Test (WCST). These findings support a diagnosis of acquired dementia.
Table
Abnormal findings on Mr. L’s neuropsychological testing
| Cognitive domain | Test | Score | Interpretation |
|---|---|---|---|
| Mental status and effort | |||
| Mental status | MMSE total score | 28/30 | 2 of 3 items recalled after delay |
| Orientation | MMSE orientation questions | 9/10 | Date off by 4 days |
| Premorbid IQ estimate | WRAT-4 Reading Standard | 66th percentile | Within normal limits. Inconsistent with educational attainment, but could be impacted by temporal lobe findings |
| Verbal memory | |||
| Immediate memory | RBANS Immediate Memory Index (List and Story Learning) | 1st percentile | Severe impairment |
| Delayed memory | RBANS Delayed Memory Index | 1st percentile | Severe impairment |
| Recognition memory | List Learning | Severe impairment | |
| Visuospatial memory | |||
| Delayed memory | RBANS Figure Recall | 3rd percentile | Severe impairment |
| Executive functioning | |||
| Cognitive flexibility | Trails B | 10th percentile | Severe impairment based on educational attainment |
| WCST | Low scores: Nonperseverative errors, perseverative errors, and categories completed | ||
| * Tests of mental status effort, visuomotor processing speed, confrontation naming, visuospatial function, attention, and executive functioning fluency/initiation were within normal limits | |||
| MMSE: Mini Mental State Exam; WRAT: Wide Range Achievement Test; RBANS: Repeatable Battery for the Assessment of Neuropsychological Status; WCST: Wisconsin Card Sorting Test | |||
The authors’ observations
Mr. L’s history, cognitive testing, head imaging, and behavioral observations suggest that several pathogenic factors contribute to his impaired functioning. First, he describes a TBI of unknown severity occurring in 1975. Although brain scans did not show evidence of midline shift or encephalomalacia, a direct blow to the head after falling from a height combined with possible post-injury seizures suggests a TBI of at least moderate severity.
Second, Mr. L describes an incident in which he required inpatient respiratory assistance. Although the precipitating medical event was unclear, anoxia or hypoxia is likely. A recent CT revealed low attenuation in the left temporal region that could represent an infarct.
Mr. L’s severe memory impairment and moderate to severe impairment in cognitive flexibility are commonly reported after a TBI of moderate severity. If an ischemic incident were the primary contributor, a lateralized pattern of cognitive dysfunction—which Mr. L does not exhibit—would be expected.
Although Mr. L likely has vascular dementia, his MRI findings do not indicate sufficient disease to account for his memory scores. Vascular dementia is associated with slow, stepwise cognitive deterioration, which is not consistent with severely impaired memory in a 56-year-old patient.
Finally, alcoholism is associated with cognitive difficulty in memory, visuospatial functioning, and abstract reasoning. Mr. L demonstrated significant difficulty in memory and abstract reasoning, but his visuospatial functioning was largely intact. In the absence of Wernicke’s encephalopathy, chronic alcoholics generally do not show memory decrements in line with Mr. L’s. His MRI results indicated only minimal ventricular and sulcal enlargement. Because atrophy is present in approximately 60% of chronic alcoholics, this finding provides evidence of a contribution, but the other contributory factors are associated with more definitive medical outcomes. Thus, alcoholism must be viewed as a secondary contributor to Mr. L’s impaired functioning.
Taking into account all known contributors, TBI emerges as the primary diagnosis.
Consider neurologic injury
Recognizing and characterizing personality changes related to neurologic injury and disease is often problematic and unreliable, even when psychometrically validated instruments and structured diagnostic interviews are used (Box 1).1-5 Mr. L’s presentation differed from the more commonly reported “impulsive aggression” associated with closed head injury. Sequelae from TBI were contributing to his clinical presentation but was obscured by his shallow and silly affect, inability to accurately assess social cues, and lack of empathy.
Mr. L reported suffering a head injury from falling off a ladder. Personality changes that result from traumatic brain injury (TBI) of the sudden deceleration type—even when mild—are frequently referable to the frontal lobe, especially focal orbital and/or ventromedial damage of the prefrontal cortex.1-5 This is because of the physical proximity of the sphenoid wing to the orbitofrontal region and effects of shearing.
As a result of this damage, patients lack insight into their accompanying cognitive and behavioral abnormalities, such as the egocentricity and impaired empathy shown by Mr. L. These changes might not be detected in clinical interviews and over brief periods.2 Appreciating an acquired personality disturbance may require evaluating the patient’s behavior over months or years.2
