IGF1 treated patients do not show the same decrease in endurance to testing as untreated RTT patients. Endurance refers to the decrease in social/cognitive rating (RSS) from the beginning to the end of each visit (T0 and T1). In untreated patients, there is a significant decrease in scores from the start to the end of testing at T1. In treated patients, such a decrease was not seen following IGF-1 treatment. Recall that an increasing (positive on the graph above) score indicates improvement in social and cognitive ability.