Working memory and response inhibition as one integral phenotype of adult ADHD? A behavioral and imaging correlational investigation.
OBJECTIVE
It is an open question whether working memory (WM) and response inhibition (RI) constitute one integral phenotype in attention deficit hyperactivity disorder (ADHD).


METHODS
The authors investigated 45 adult ADHD patients and 41 controls comparable for age, gender, intelligence, and education during a letter n-back and a stop-signal task, and measured prefrontal oxygenation by means of functional near-infrared spectroscopy.


RESULTS
The authors replicated behavioral and cortical activation deficits in patients compared with controls for both tasks and also for performance in both control conditions. In the patient group, 2-back performance was correlated with stop-signal reaction time. This correlation did not seem to be specific for WM and RI as 1-back performance was correlated with go reaction time. No significant correlations of prefrontal oxygenation between WM and RI were found.


CONCLUSIONS
The authors' findings do not support the hypothesis of WM and RI representing one integral phenotype of ADHD mediated by the prefrontal cortex.
University Regensburg, Germany. martin.schecklmann@medbo.de
Martin
M
Schecklmann
Ann-Christine
AC
Ehlis
Michael M
MM
Plichta
Thomas
T
Dresler
Monika
M
Heine
Andrea
A
Boreatti-Hümmer
Marcel
M
Romanos
Christian
C
Jacob
Paul
P
Pauli
Andreas J
AJ
Fallgatter
D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000145:classification / Q000378:metabolism / Q000503:physiopathology*; D005260:Female; D059907:Functional Neuroimaging; D006801:Humans; D007175:Impulsive Behavior / Q000378:metabolism / Q000503:physiopathology; D007266:Inhibition, Psychological; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009483:Neuropsychological Tests; D010100:Oxygen; D010641:Phenotype; D017397:Prefrontal Cortex / Q000378:metabolism / Q000503:physiopathology*; D011569:Psychiatric Status Rating Scales; D019265:Spectroscopy, Near-Infrared / Q000295:instrumentation / Q000379:methods*; D055815:Young Adult
D010100:Oxygen