Inefficient cognitive control in adult ADHD: evidence from trial-by-trial Stroop test and cued task switching performance.
BACKGROUND
Contemporary neuropsychological models of ADHD implicate impaired cognitive control as contributing to disorder characteristic behavioral deficiencies and excesses; albeit to varying degrees. While the traditional view of ADHD postulates a core deficiency in cognitive control processes, alternative dual-process models emphasize the dynamic interplay of bottom-up driven factors such as activation, arousal, alerting, motivation, reward and temporal processing with top-down cognitive control. However, neuropsychological models of ADHD are child-based and have yet to undergo extensive empirical scrutiny with respect to their application to individuals with persistent symptoms in adulthood. Furthermore, few studies of adult ADHD samples have investigated two central cognitive control processes: interference control and task-set coordination. The current study employed experimental chronometric Stroop and task switching paradigms to investigate the efficiency of processes involved in interference control and task-set coordination in ADHD adults.


METHODS
22 adults diagnosed with persistent ADHD (17 males) and 22 matched healthy control subjects performed a manual trial-by-trial Stroop color-word test and a blocked explicitly cued task switching paradigm. Performance differences between neutral and incongruent trials of the Stroop task measured interference control. Task switching paradigm manipulations allowed for measurement of transient task-set updating, sustained task-set maintenance, preparatory mechanisms and interference control. Control analyses tested for the specificity of group x condition interactions.


RESULTS
Abnormal processing of task-irrelevant stimulus features was evident in ADHD group performance on both tasks. ADHD group interference effects on the task switching paradigm were found to be dependent on the time allotted to prepare for an upcoming task. Group differences in sustained task-set maintenance and transient task-set updating were also found to be dependent on experimental manipulation of task preparation processes. With the exception of Stroop task error rates, all analyses revealed generally slower and less accurate ADHD group response patterns.


CONCLUSIONS
The current data obtained with experimental paradigms deliver novel evidence of inefficient interference control and task-set coordination in adults with persistent ADHD. However, all group differences observed in these central cognitive control processes were found to be partially dependent on atypical ADHD group task preparation mechanisms and/or response inconsistency. These deficiences may have contributed not only to inefficient cognitive control, but also generally slower and less accurate ADHD group performance. Given the inability to dissociate these impairments with the current data, it remains inconclusive as to whether ineffecient cognitive control in the clinical sample was due to top-down failure or bottom-up engagement thereof. To clarify this issue, future neuropsychological investigations are encouraged to employ tasks with significantly more trials and direct manipulations of bottom-up mechanisms with larger samples.
King
Joseph A
JA
Max Planck Institute for Human Cognitive and Brain Sciences, Department of Cognitive Neurology, Stephanstr, 1A, D-04103 Leipzig, Germany. king@cbs.mpg.de.
Colla
Michael
M
Brass
Marcel
M
Heuser
Isabella
I
von Cramon
Dy
D
Biol Psychiatry. 2000 Jul 1;48(1):9-20
10913503
Psychol Res. 2000;63(3-4):234-49
11004878
Psychol Med. 2004 May;34(4):681-92
15099422
Biol Psychiatry. 1999 Jun 15;45(12):1542-52
10376114
Behav Brain Funct. 2006;2:4
16441891
Eur Arch Psychiatry Clin Neurosci. 2004 Dec;254(6):365-71
15538605
Am J Psychiatry. 2005 Sep;162(9):1621-7
16135620
Biol Psychiatry. 2007 Jun 15;61(12):1361-9
16950217
Am J Psychiatry. 1999 Jun;156(6):891-6
10360128
Neuroimage. 2004 Dec;23(4):1317-25
15589096
Psychol Med. 2005 Jun;35(6):807-16
15997601
Cereb Cortex. 2002 Sep;12(9):908-14
12183390
Brain. 2003 Nov;126(Pt 11):2363-80
12876148
Psychol Med. 2005 Aug;35(8):1097-108
16116936
Psychol Bull. 2006 Jul;132(4):560-81
16822167
Arch Clin Neuropsychol. 2003 Apr;18(3):317-30
14591462
Neurosci Biobehav Rev. 2003 Nov;27(7):593-604
14624804
Biol Psychiatry. 2005 Jun 1;57(11):1424-35
15950017
J Am Acad Child Adolesc Psychiatry. 2004 Nov;43(11):1430-40
15502603
Biol Psychiatry. 2003 Dec 15;54(12):1465-8
14675812
J Atten Disord. 2006 Feb;9(3):534-42
16481670
Behav Brain Sci. 2005 Jun;28(3):397-419; discussion 419-68
16209748
J Clin Exp Neuropsychol. 2006 Oct;28(7):1113-26
16840239
Nervenarzt. 2003 Nov;74(11):987-93
14598035
J Child Psychol Psychiatry. 2005 Feb;46(2):150-65
15679524
Cereb Cortex. 2007 Jun;17(6):1364-75
16920883
Trends Cogn Sci. 2006 Mar;10(3):117-23
16460990
Biol Psychiatry. 2006 Nov 15;60(10):1088-97
16806097
J Psychiatr Res. 2007 Dec;41(11):934-41
17303167
Neurosci Biobehav Rev. 2000 Jan;24(1):3-5
10654653
J Consult Clin Psychol. 2002 Feb;70(1):153-7
11860041
Clin Psychol Rev. 2006 Aug;26(4):433-44
16480802
Neuroimage. 2004 Oct;23(2):604-12
15488410
J Exp Psychol Learn Mem Cogn. 2005 Nov;31(6):1477-91
16393058
Biol Psychiatry. 2005 Jun 1;57(11):1263-72
15949998
Am J Psychiatry. 1998 Apr;155(4):493-8
9545994
Biol Psychiatry. 2005 Jun 1;57(11):1336-46
15950006
J Clin Exp Neuropsychol. 2005 Apr;27(3):278-98
15969353
J Abnorm Psychol. 2005 May;114(2):197-215
15869351
JAMA. 2002 Oct 9;288(14):1740-8
12365958
J Atten Disord. 2002 Jun;6(1):1-4
12045755
Psychol Bull. 1991 Mar;109(2):163-203
2034749
J Abnorm Psychol. 2005 Nov;114(4):706-17
16351391
Psychiatry Res. 1995 Jan 31;56(1):59-70
7792343
Neuropsychology. 2004 Jul;18(3):485-503
15291727
Dev Psychopathol. 2005 Summer;17(3):785-806
16262992
Am J Psychiatry. 2005 Sep;162(9):1605-13
16135618
J Child Psychol Psychiatry. 2006 Jun;47(6):568-72
16712633
Arch Gen Psychiatry. 2006 May;63(5):540-9
16651511
J Am Acad Child Adolesc Psychiatry. 2001 Nov;40(11):1277-84
11699801
Biol Psychiatry. 2005 Jun 1;57(11):1273-84
15949999
Nervenarzt. 2003 Oct;74(10):939-46
14655655
J Psychiatr Res. 2008 Jun;42(7):587-95
17698080
Acta Psychol (Amst). 2000 May;104(2):167-90
10900704
Child Neuropsychol. 2006 Apr;12(2):125-40
16754533
J Abnorm Child Psychol. 2000 Jun;28(3):213-26
10885680
Trends Cogn Sci. 2003 Mar;7(3):134-140
12639695
Neuropsychology. 1998 Jul;12(3):414-25
9673997
J Atten Disord. 2003 Nov;7(2):93-100
15018358
Biol Psychiatry. 2005 Jun 1;57(11):1416-23
15950016
Nervenarzt. 2002 Sep;73(9):830-8
12215873
Biol Psychiatry. 2004 Sep 1;56(5):333-9
15336515
Behav Brain Funct. 2006;2:30
16925830
Psychol Bull. 1997 Jan;121(1):65-94
9000892
Trends Neurosci. 2006 Aug;29(8):474-80
16820224
Neuron. 2003 Aug 14;39(4):713-26
12925284
Dev Psychol. 2001 Sep;37(5):715-30
11552766
Biol Psychiatry. 2006 Nov 15;60(10):1071-80
16876137
Biol Psychiatry. 2006 Apr 1;59(7):643-51
16197925
Arch Clin Neuropsychol. 2004 Sep;19(6):725-43
15288327
Eur Arch Psychiatry Clin Neurosci. 2002 Aug;252(4):177-84
12242579
Eur Arch Psychiatry Clin Neurosci. 2006 Sep;256 Suppl 1:i32-41
16977550
Neurosci Biobehav Rev. 2003 Nov;27(7):583-92
14624803
Exp Brain Res. 2003 Oct;152(4):444-52
12879174