title: When solving 22-7 is much more difficult than 99-12.
abstract: We describe the case of a 69-year-old professor of mathematics (GV) who was examined 2 years after left-hemispheric capsular-thalamic haemorrhage. GV showed disproportionate impairment in subtractions requiring borrowing (22 - 7). For large subtraction problems without borrowing (99 - 12) performance was almost flawless. Subtractions with borrowing mostly relied on inadequate attempts to invert subtractions into the corresponding additions (22 - 7 = x as 7 + x = 22). The hypothesis is advanced that difficulty in the inhibitory components of attention tasks (Stroop test, go-no-go task) might be the responsible factor of his calculation impairment. A deficit in subtractions with borrowing might be related to left-hemispheric damage involving thalamo-cortical connections.
authors.affiliation: Hildebrand Clinic, Rehabilitation Center, Brissago, Switzerland.
authors.forename: Antonio
authors.initials: A
authors.lastname: Carota
authors.forename: Paola
authors.initials: P
authors.lastname: Marangolo
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Markowitsch
authors.forename: Pasquale
authors.initials: P
authors.lastname: Calabrese
mesh_terms: D000368:Aged; D001288:Attention / Q000502:physiology; D001921:Brain / Q000473:pathology; D003071:Cognition / Q000502:physiology; D056344:Executive Function; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D020300:Intracranial Hemorrhages / Q000523:psychology*; D008297:Male; D008433:Mathematics; D008568:Memory / Q000502:physiology; D008606:Mental Processes / Q000502:physiology; D011340:Problem Solving; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D057190:Stroop Test; D013786:Thalamic Diseases / Q000523:psychology*