Parent-reported outcome measures evaluating communication in individuals with rare neurodevelopmental disorders: A systematic review.

Only English-language publications were included, and the authors accept they may have missed some rare conditions and that the list of disorders may not be exhaustive. Independent double screening was done, but agreement between reviewers was formally compared on only a randomly selected 10% of records. The validation studies are mostly small: three of the four studies testing how items group together were rated only 'adequate' because the sample was too small for the number of items in the measure. Content validity was rated 'doubtful' for some measures because they were checked as a whole rather than item by item, and comparisons against other measures were rated only 'adequate' because those comparator measures are themselves not validated in these disorders. No measure had been checked for measurement error or for behaving the same way across cultures, and only one (the Vineland II) had data on detecting change, so no one knows what a change in score means for these children. Psychometric data exist for only a handful of conditions, so a measure validated in one disorder may not transfer to another, and the review does not appraise the quality of the 56 included studies or of the trials whose communication results it counts. The paper is not always consistent about the number of validated measures, describing six in its conclusion and seven in one table.

Several authors have consultancy or clinical-trial relationships with companies developing treatments for these conditions, including Marinus, Acadia, Avexis, Anavex, Newron, Stoke Therapeutics, Takeda, Ionis, Neurogene, Ovid, Ultragenyx, Zogenix/UCB, Encoded and Capsida, with payment made to their departments, and some sit on advisory boards of rare-disease foundations. Two report grant funding from the NIH and from rare-disease charities. Three authors declare no interests that could pose a conflict. The authors state their consultancies are unrelated to this work.

Do not read this review as evidence that any treatment improves communication in these conditions. It catalogues and appraises the measuring tools, not the trials. It reports that 6 trials found a significant group difference and 9 did not, but states these results are difficult to interpret because no one has worked out what a change in score actually means for these children, and several measures bottom out in the most severely affected.