Association between response inhibition and working memory in adult ADHD: a link to right frontal cortex pathology?
BACKGROUND
We sought to assess the relationship between response inhibition and working memory in adult patients with attention-deficit/hyperactivity disorder (ADHD) and neurosurgical patients with frontal lobe damage.


METHODS
The stop-signal reaction time (SSRT) test and a spatial working memory (SWM) task were administered to 20 adult patients with ADHD and a group of matched controls. The same tasks were administered to 21 patients with lesions to right frontal cortex and 19 patients with left frontal lesions.


RESULTS
The SSRT test, but not choice reaction time, was significantly associated with search errors on the SWM task in both the adult ADHD and right frontal patients. In the right frontal patients, impaired performance on both variables was correlated with the volume of damage to the inferior frontal gyrus.


CONCLUSIONS
Response inhibition and working memory impairments in ADHD may stem from a common pathologic process rather than being distinct deficits. Such pathology could relate to right frontal-cortex abnormalities in ADHD, consistent with prior reports, as well as with the demonstration here of a significant association between SSRT and SWM in right frontal patients.
Clark
Luke
L
Department of Experimental Psychology, University of Cambridge School of Clinical Medicine, Addenbrooke's Hospital, Cambridge, United Kingdom. lc260@cam.ac.uk
Blackwell
Andrew D
AD
Aron
Adam R
AR
Turner
Danielle C
DC
Dowson
Jonathan
J
Robbins
Trevor W
TW
Sahakian
Barbara J
BJ
D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology*; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology*; D008570:Memory, Short-Term; D009483:Neuropsychological Tests; D011930:Reaction Time; D012720:Severity of Illness Index; D013028:Space Perception / Q000502:physiology