BlinkLab (ASX:BB1) said the firm and Mental Care Group expanded the Attention Deficit and Hyperactivity Disorder (ADHD) clinical study from one to five European clinical sites to "better capture the clinical heterogeneity of ADHD and ensure broader generalizability," according to a Friday Australian bourse filing.

Including the initial group, the study is estimated to report data from around 300 participants by the end of the year.

The new sites have been recently onboarded and will actively participate in the study enrollment.

The data from the study will form a critical part of BlinkLab's clinical evidence package under the European regulatory framework.

Two clinical sites are actively recruiting participants in the pilot phase of its US autism trial, PriMED Clinical Research in Ohio and North Shore Pediatric Therapy in Illinois. Two more sites are fully onboarded for the main phase of the study, the University of Nebraska Medical Center in Nebraska and the Southwest Autism Research and Resource Center in Arizona.