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fMRI and psychometrics of visuo-spatial working memory in children with and without ADHD
NeuroImage
13, Number
6, 2001,
Part 2 of 2 Parts 10
E kL@
MEMORY
fMR1 and psychometrics of visuo-spatial working memory in children with and without ADHD Helena Westerberg, Hans Forssberg, Torkel Klingberg Department of Woman and Child Health, Karolinska Institute, Stockholm, Sweden Introduction: Difficulties with working memory are hypothesized to be a core deficit in Attention Deficit/Hyperactivity Disorder (ADHD) (Barkley,1997). For that reason we wanted to investigate how sensitive a test for working memory (WM) would be in comparison with two other tests commonly used in ADHDdiagnostics, - the Continuous Performance Test (CPT) and the Go/No-go test. The CPT was of special interest because it incorporates several cognitive subcomponents in the same task, including WM, Speed of Processing measured through ChoiceReaction time (RT) and Control of Inhibition. A second idea was to administrate and compare several tests that more specifically tax each of these components, among them the WM-test. The purpose was to see if a single component approach would allow us to find more stringent measures of the cognitive deficits in ADHD. We did also compare brain activity in children with and without ADHD while performing a WM task. Methods: There were twelve subjects in the control group and eleven subjects with ADHD. We programmed and administrated four computerized tests in the E-primea software milieu. This was done outside the scanner. The tests were: Choice Reaction Time (RT), Go/No-go (Trommer 1991), Continuous Performance Test (Gordon 1988) and Working Memory (WM) location span (Fry and Hale 1994). A very similar WM-test was also given during fMR1. fMRI was conducted by a 1.5 T GE scanner with T2*-weighted spiral echo-planar image pulse sequence. Data analysis: The data were analyzed with SPM99. Motion during scanning was estimated by six parameters (three translations, three rotations) which were used to realign the functional images to the first image in the series, and later used as confounds in the statistical analysis. Multiple regression was used for the psychometrical data analyses, Results: Psychometrics: We found that visuo-spatial WM and choice RT showed significant differences between the ADHD and the Control group (P=O.O019 and P=O.O017, respectively). Neither the CPT (P= 0.20) nor the Go/No-go test (P= 0.99) separated between the groups. fMR1: The main difference between the ADHD and control groups was found in the cortex lining the intra parietal sulcus and a minor location in the superior frontal sulcus. The activation in these areas correlates with the subjects WM capacity, i.e. more activity and higher level of performance in the control group compared to the performance of the ADHD group. Conclusion: There were significant differences in brain activity between the ADHD and control groups. These differences correlated with the subjects capacity on the WM task. These findings were in agreement with the psychometric results; The WM task and the choice-RT task did discriminate better than the well known CPT and Go/No-go tests between the ADHD and the Control group. REFERENCES Barkley, R. A.1997, Psychological Bulletine, 121, 65-94. Fry and Hale 1996, Psychological Science, 7, 237-241. Gordon, M.1988, Journal of Clinical Psychology, 44. Trommer et al 1991, Journal of Child Neurology, 6, 126-9.
S761
13, Number
6, 2001,
Part 2 of 2 Parts 10
E kL@
MEMORY
fMR1 and psychometrics of visuo-spatial working memory in children with and without ADHD Helena Westerberg, Hans Forssberg, Torkel Klingberg Department of Woman and Child Health, Karolinska Institute, Stockholm, Sweden Introduction: Difficulties with working memory are hypothesized to be a core deficit in Attention Deficit/Hyperactivity Disorder (ADHD) (Barkley,1997). For that reason we wanted to investigate how sensitive a test for working memory (WM) would be in comparison with two other tests commonly used in ADHDdiagnostics, - the Continuous Performance Test (CPT) and the Go/No-go test. The CPT was of special interest because it incorporates several cognitive subcomponents in the same task, including WM, Speed of Processing measured through ChoiceReaction time (RT) and Control of Inhibition. A second idea was to administrate and compare several tests that more specifically tax each of these components, among them the WM-test. The purpose was to see if a single component approach would allow us to find more stringent measures of the cognitive deficits in ADHD. We did also compare brain activity in children with and without ADHD while performing a WM task. Methods: There were twelve subjects in the control group and eleven subjects with ADHD. We programmed and administrated four computerized tests in the E-primea software milieu. This was done outside the scanner. The tests were: Choice Reaction Time (RT), Go/No-go (Trommer 1991), Continuous Performance Test (Gordon 1988) and Working Memory (WM) location span (Fry and Hale 1994). A very similar WM-test was also given during fMR1. fMRI was conducted by a 1.5 T GE scanner with T2*-weighted spiral echo-planar image pulse sequence. Data analysis: The data were analyzed with SPM99. Motion during scanning was estimated by six parameters (three translations, three rotations) which were used to realign the functional images to the first image in the series, and later used as confounds in the statistical analysis. Multiple regression was used for the psychometrical data analyses, Results: Psychometrics: We found that visuo-spatial WM and choice RT showed significant differences between the ADHD and the Control group (P=O.O019 and P=O.O017, respectively). Neither the CPT (P= 0.20) nor the Go/No-go test (P= 0.99) separated between the groups. fMR1: The main difference between the ADHD and control groups was found in the cortex lining the intra parietal sulcus and a minor location in the superior frontal sulcus. The activation in these areas correlates with the subjects WM capacity, i.e. more activity and higher level of performance in the control group compared to the performance of the ADHD group. Conclusion: There were significant differences in brain activity between the ADHD and control groups. These differences correlated with the subjects capacity on the WM task. These findings were in agreement with the psychometric results; The WM task and the choice-RT task did discriminate better than the well known CPT and Go/No-go tests between the ADHD and the Control group. REFERENCES Barkley, R. A.1997, Psychological Bulletine, 121, 65-94. Fry and Hale 1996, Psychological Science, 7, 237-241. Gordon, M.1988, Journal of Clinical Psychology, 44. Trommer et al 1991, Journal of Child Neurology, 6, 126-9.
S761