Long-Term Neuropsychological Outcomes of Childhood Onset Acute Disseminated Encephalomyelitis (ADEM): a Meta-Analysis

The long-term neurocognitive prognosis of childhood onset acute disseminated encephalomyelitis (ADEM) is unclear. This review and quantitative synthesis of the available literature examined whether there are long-term impacts of childhood ADEM on neurocognitive functioning. A search of online databases (MEDLINE, EMBASE, EBSCO CINAHL, PsycINFO and the Cochrane Database of Systematic Reviews) from their inception to October 2015 and reference lists identified 13 papers eligible for inclusion in the systematic review; seven of these were eligible for inclusion in meta-analyses. The systematic review indicated that, at a group level there is a positive long-term neuropsychological outcome from childhood onset ADEM. However, despite the apparent absence of long-term negative impacts of ADEM at a group level, at an individual level impairments in the areas of IQ, attention, executive functioning, processing speed, learning and memory, visuospatial skills and internalising symptoms were found in up to 43% of patients when aggregated across the studies. No significant negative effect of ADEM for any of the neuropsychological domains examined was found in meta-analyses. However, the effects for Processing Speed (r _mean = −0.296 (CI 95% = −0.605-0.013)) and Internalising symptoms (r _mean = 0.242 (CI 95% = −0.014-0.564)) approached significance (p = 0.06), suggesting a trend towards ADEM leading to long-term reduced processing speed and elevated internalising symptoms. Together, our findings suggest that despite a generally positive neurocognitive outcome post childhood ADEM there are a subset of individuals who can suffer from ongoing specific cognitive impairments. Clinical implications and research priorities are discussed.