An ERP investigation of response inhibition in adults with DCD Elisabeth Hill Duncan Brown José van Velzen
Background Response inhibition - crucial for goal-directed behaviour in changing environment Frontoparietal network implicated (behavioural / ERP) Mixed findings in children with DCD (e.g. Wilson et al., 1997; Mandich et al. 2002, 2003; Querne et al. 2009) Adults?
Aims Enhance understanding of response inhibition in DCD (Go/NoGo task) Identify neurological mechanisms involved (with benefits for theory and intervention?) Provide behavioural and neurophysiological evidence for continuation of coordination difficulty in adults with DCD
Movement battery: p<.001 Participants
MIDLINE CROSSING STRAIGHT Infra-red starting position Possible probe LED Target button Experimental set-up Go/NoGo (delayed response) paradigm
1000 msec between trials Experimental set-up
1000 msec between trials 900msec Hand cue: 200 msec
1000 msec between trials 900msec Hand cue: 200 msec
1000 msec between trials 900msec Probe flashed: 100 msec Hand cue: 200 msec
GO 1000 msec between trials 900msec 200msec Probe flashed: 100 msec STOP Hand cue: 200 msec **
GO 1000 msec between trials 900msec 200msec Response initiated or withheld Probe flashed: 100 msec STOP Hand cue: 200 msec ** N msec post STOP P msec post STOP
Dependent variables Compare: Group (DCD vs. typical) Movement type (straight vs. midline) Behavioural results: Inhibitory errors (fail to STOP) ERPs: N200; P300
ERP predictions N200 / P300: increased in midline vs. straight movement (typicals) decreased and delayed in DCD (vs. typical)
Behavioural results group p<.001; movement p.001 group x condition p<.05
N200 ( msec post STOP) Frontal regions group.005; movement ns group x movement ns
P300 ( msec post STOP, shown msec ) Central regions group ns; movement ns group x movement ns
Summary More inhibitory errors in DCD vs. typical group N200: Greater enhancement in typical vs. DCD group P300: No differences between groups
Implications Inhibition (Go/No go) difficulties in adults with DCD Biological underpinning (electrophysiological correlates) Possible involvement of anterior cingulate cortex (ACC), prefrontal cortex (PFC) cf. N200? Lifespan development
–EEG was recorded continuously with Ag/AgCl electrodes via 64 channel Biosemi system with linked earlobe reference. –Signals were amplified with a bandpass width of Hz and sampling rate was set at 512 Hz. –Data segments were epoched to 100 ms prior to onset of probe onset and 500 ms after probe onset for each movement condition. –Individual trials containing eye movement artifacts and errors were rejected before the averaging process. –Early visual-spatial potential N1(amplitude) was isolated (defined as negative going peak ms post probe onset) and used for comparison of sensory gating of attended locations within visual perception EEG acquisition