B - 11 Alien Limb and Corticobasal Degeneration: a Neuropsychological Case Study

Abstract Objective The patient presented with alien limb, frequently associated with corticobasal degeneration, an atypical parkinsonian syndrome with rigidity, akinesia, dystonia, cortical sensory deficit, and apraxia. Subjective memory complaints are also common. Neuropsychological performance typically includes poor performance on verbal fluency and measures tapping into executive functioning, but confrontation naming and verbal comprehension are initially well-preserved. Method The patient is a right-handed 69-year-old male who developed the sensation of alien limb in his left arm 2 years prior, in which his left hand did not feel “real.” Additionally, the patient presented with memory difficulties, mild word-finding problems, and physical/motor complaints (i.e., limb apraxia, tremor, bradykinesia, occasional limb dystonia, and postural instability) for approximately 2 years. The patient sought neuropsychological assessment to clarify his cognitive functioning in light of his neurologic symptoms. Results Premorbid functioning was in the exceptionally high range, with 18 years of education. Neuropsychologically, immediate memory was generally average, and generally low average delayed memory and recognition abilities. Mild inefficiencies were observed in executive functioning and semantic fluency. Otherwise, the patient performed generally average across other tasks of language, including confrontation naming, and attention. Conclusions In light of the literature, it is expected that corticobasal degeneration will be associated with subjective memory difficulties, executive dysfunction and poor verbal fluency. The patient presented with generally intact memory, mild executive dysfunction, and poor semantic fluency abilities. Given the patient’s high intelligence, he may be more sensitive to cognitive lapses. Neuropsychological results, along with his reported parkinsonian features, are fairly consistent with possible incipient corticobasal degeneration.