42 - Despite inattention, visuomotor task correlates with dorsal stream function after neonatal encephalopathy.

Poster Number: 42
Publication Number: 42.222

Background: The dorsal stream pathway is involved in processing visuospatial relationships and visually guided actions, and is impacted by hypoxia-ischemia. The role of attention to the assessment of visuospatial function in children after neonatal encephalopathy (NE) needs to be better understood.

Objective: To evaluate the role of attention in assessing dorsal stream pathway function using a visuomotor task in early school-aged children after NE.

Design/Methods: We assessed reaction time (RT) in a sustained attention visuomotor task during magnetoencephalography (MEG) recording in participants 5.5±0.3 years, a prospective cohort of NE following therapeutic hypothermia. Participants were instructed to press a button as quickly as possible after the offset of a visual grating stimulus. Trials with RT >2 secs were discarded. Inattention was evaluated by standard deviation of RT, RT difference between the first and last 15 trials, and percentage of missed visual stimuli and additional pressed buttons. These measures were compared with measures of attention on the Child Behavior Checklist (CBCL) parent questionnaire. Dorsal stream pathway function was assessed by correlating RT with standardized neuropsychological testing using Wechsler Preschool and Primary Scale of Intelligence 4th edition (WPPSI-IV).

Results: RT was available for 28 participants (71% male, Sarnat mild 2/moderate 26, 25% brain injury on MRI) with a median of 95.5 trials. The mean individual RT standard deviation (403msec) corresponded to 54% of the mean RT (740±198msec). Paired t-tests showed slower mean (p=0.008) and median RT (p=0.012) in the last block of trials. Median missed visual stimuli (17.2%) and additional pressed buttons (41.9%) were high. CBCL Attention (57.5±8.3) and ADHD (54.8±6.3) Problem scales were higher than norm (50, p< 0.001) but less than clinical significance (≥70, p>0.05). Pearson correlation was not associated with any measure of RT inattention and CBCL attention (p>0.05). For WPPSI-IV (Table 1), mean RT showed a significant inverse correlation with Full-scale IQ (r=-0.39, p=0.049), and Processing Speed Index (r= -0.41, p=0.032), the latter measures visual discrimination and motor response.

Conclusion(s): At early school-age after NE, inattention in a MEG sustained attention visuomotor task does not correlate with clinically reported measures of attention abilities. Still, the sustained attention task is an appropriate measure of dorsal stream pathway function given the correlation with neuropsychological tests of processing speed. These findings will be important foundation in further analysis of dorsal stream functioning.