Maayke Hunfeld

214 Chapter 7 Neuropsychological outcomes At 3-6 months a selection bias may have occurred because of a trend ( p =0.07) towards more favourable PCPC scores in the neuropsychologically tested group compared with the non-tested group. Therefore the finding that OHCA children only scored worse on sustained attention and processing speed and not on other outcomes at this time- point should be interpreted with caution. At 24 months follow-up, OHCA children obtained worse intelligence scores compared to norms, which is consistent with outcomes of other paediatric post- CA studies (11, 12, 30) . Additionally, worse scores for attention, cognitive flexibility, and processing speed were detected. This was also found in the THAPCA trial in which CA survivors were tested one year after CA (30) . This is remarkable, since there are differences between the present study and the THAPCA study. The THAPCA trial 1). Included IHCA and OHCA children when they were unresponsive and mechanically ventilated after ROC, creating a population with possibly more severely affected children, 2). Included a fraction of eligible children presenting to the hospital (295/1355, 22%), 3). Had a different study design comparing the efficacy of therapeutic hypothermia with therapeutic normothermia, 4). Had a smaller inclusion period; 2009- 2012 in THAPCA versus 2012-2017 in present study, and 5). The follow-up included a cross-sectional assessment moment at 1 year follow-up versus longitudinal follow-up over 2 years in the present study. Lower intelligence scores were also found at 2 years follow-up in a large heterogeneous cohort of critically ill PICU survivors (n=786), implicating that critical illness itself has negative impact on intelligence (31) . In those children who were assessed repeatedly, no significant changes were found in intelligence scores and neuropsychological outcomes over time. Unfortunately, the sample with repeated measures was small (median n=5 per domain) with a wide age range. This makes it difficult to draw definite conclusions. Intelligence scores of OHCA children did not correlate with PCPC scores. Silverstein et al. found that PCPC scores were correlated with scores on the Vineland Adaptive Behavior Scales (VABS) (29). However, their inclusion criteria and assessment method (parent-reported versus objectively tested intellectual functioning) differed from our study, and it is not possible to compare the score of the VABS with tested intellectual functioning. In conclusion, although the gross outcome during follow-up was favourable in our OHCA children, they do have cognitive deficits, making them cognitively vulnerable during development. What does this mean for the future of these children? Due to several factors, this is difficult to predict from our study: the median age in our cohort was 48 months at arrest, with a wide age range of 3 months up to 18 years. Besides, the