Unravelling developmental disregard in children with unilateral cerebral palsy by measuring event-related potentials during a simple and complex task

Abstract

BackgroundIn a subset of children with unilateral Cerebral Palsy (CP) a discrepancy between capacity and performance of the affected upper limb can be observed. This discrepancy is known as Developmental Disregard (DD). Though the phenomenon of DD has been well documented, its underlying cause is still under debate. DD has originally been explained based on principles of operant conditioning. Alternatively, it has been proposed that DD results from a diminished automaticity of movements, resulting in an increased cognitive load when using the affected hand. To investigate the amount of involved cognitive load we studied Event-Related Potentials (ERPs) preceding task-related motor responses during a single-hand capacity and a dual-hand performance task. It was hypothesised that children with DD show alterations related to long-latency ERP components when selecting a response with the affected upper limb, reflecting increased cognitive load in order to generate an adequate response and especially so within the dual-hand task.MethodsFifteen children with unilateral CP participated in the study. One of the participants was excluded due to major visual impairments. Seven of the remaining participants displayed DD. The other seven children served as a control group. All participants performed two versions of a cue-target paradigm, a single-hand capacity and a dual-hand performance task. The ERP components linked to target presentation were inspected: the mid-latency P2 component and the consecutive long-latency N2b component.ResultsIn the dual-hand performance task children with DD showed an enhancement in mean amplitude of the long-latency N2b component when selecting a response with their affected hand. No differences were found regarding the amplitude of the mid-latency P2 component. No differences were observed regarding the single-hand capacity task. The control group did not display any differences in ERPs linked to target evaluation processes between both hands.ConclusionThese electrophysiological findings show that DD is associated with increased cognitive load when movements are prepared with the affected hand during a dual-hand performance task. These findings confirm behavioural observations, advance our insights on the neural substrate of DD and have implications for therapy.

Event-related Potentials During Target-response Tasks to Study Cognitive Processes of Upper Limb Use in Children with Unilateral Cerebral Palsy

“…Although DD has been extensively described in the literature and different theories have emphasized the possible contribution of altered cognitive processes 5,[9][10][11] 1. Participants 1. Only include children that are diagnosed with unilateral CP as diagnosed by a medical specialist (i.e., neurologist, pediatrician).…”

“…In this respect DD has been compared to the phenomenon of post-stroke motor neglect, suggesting visuo-spatial attention deficits 9,11,12, . Alternatively, it has been proposed that the lack of use of the affected hand during crucial developmental periods does not only affect motor development, but is also associated with a delay of cognitive processes related to motor behavior 5,10 .…”

“…Apart from the traditional explanations of DD based on behavioral reinforcement theories 4 , more recent studies have emphasized the importance of cognitive factors for understanding DD 5,[9][10][11] . These theories are based on the idea that certain motor deficits in children with unilateral CP are actually caused by dysfunctional cognitive processes that are necessary for successful goal-directed motor behavior, rather than by the movement restrictions itself.…”

“…2. Only include children older than 5 years old 10,11 . NOTE: Younger children might not be able to pay attention to the task during the whole procedure.…”

Impact of mastery motivation on occupational performance outcomes following upper limb intervention for school-aged children with congenital hemiplegia

“…Therapy has been provided on either an individual basis or in groups with 1:1 or 1:2 therapist child ratio. Group models are reported to enhance motivation and allow children opportunities to problem solve with peers Zielinski, Jongsma, Baas, Aarts, & Steenbergen, 2014). To date, there has been no direct comparison of intensive group therapy with distributed models of individualized UL therapy for children with UCP.…”