Exceptional calendar calculation ability after early left hemispherectomy.
An 18-year-old male subject who had had his left hemisphere removed at age eight was better than chance at calculating the day of the week upon which dates in the past and future fell. He was able to describe his method of calculation, which relied upon both visual memory and serial calculations. The use of a serial calculation method was supported by evidence that both response time and accuracy were related to the distance in years from the current year. The use of both visual and verbal "working" memory was supported by interference effects from calendar calculations and delayed visual and verbal memory tasks. The case is discussed in terms of theories regarding similar calculation skills in idiot savants.
Dorman
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School of Human Behavior, United States International University, San Diego, CA 92131.
D000293:Adolescent; D001925:Brain Damage, Chronic / Q000503:physiopathology; D002540:Cerebral Cortex / Q000002:abnormalities / Q000601:surgery*; D004292:Dominance, Cerebral / Q000502:physiology*; D006801:Humans; D008607:Intellectual Disability / Q000503:physiopathology; D008297:Male; D011939:Mental Recall / Q000502:physiology; D009949:Orientation / Q000502:physiology; D011183:Postoperative Complications / Q000503:physiopathology*; D011340:Problem Solving / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012640:Seizures / Q000503:physiopathology / Q000601:surgery*; D012691:Serial Learning / Q000502:physiology; D013998:Time Perception / Q000502:physiology*; D014705:Verbal Behavior / Q000502:physiology; D014796:Visual Perception / Q000502:physiology