Rett syndrome, a neurodevelopmental disorder caused by MECP2 mutations, is associated with loss of purposeful hand function. The Rett Syndrome Hand Function Scale (RSHFS), an 8-level scale assessing ability to grasp and manipulate objects, is used to support consistent evaluation of standardized video footage.¹

Participants reached consensus on 2 levels of meaningful hand function improvement: First, progressing from no or assisted grasp (RSHFS 1–3) to unassisted ulnar or raking grasp (RSHFS 4–5); second, progressing further to higher RSHFS levels (pincer grasp, transfer between hands, and good approximation of hand position to object size). Rater scores were compared with established ratings with a mean (95%CI) weighted Kappa statistic above 0.5 and Fleiss Kappa of 0.52.

A standardized video recording of hand function by parents is feasible, and consensus was reached regarding a meaningful change in hand skills. Given that gains in hand function are rare in classic Rett syndrome, any consistent improvement in a clinical trial may indicate therapeutic benefit. Clinicians can be readily trained in assessing video-recorded hand function using the RSHFS and achieve moderate inter-rater reliability after short-term training. We are optimizing training material and conducting further inter- and intra-rater reliability testing. The availability of a validated, harmonized outcome measure is expected to accelerate progress towards better treatments for Rett syndrome.

¹Downs J, Dev Med Child Neurol 2010;52:817-23