Construct-irrelevant cognitive complexity of some items in the statewide grade-level assessments may impose performance barriers for students with disabilities who are ineligible for alternate assessments based on alternate achievement standards. This has spurred research into whether items can be modified to reduce complexity without affecting item construct. This study uses a generalized linear mixed modeling analysis to investigate the effects of item modifications on improving test accessibility by reducing construct-irrelevant cognitive barriers for persistently low-performing fifth-grade students with cognitive disabilities. The results showed item scaffolding was an effective modification for both mathematics and reading. Other modifications, such as bolding/underlining of key words, hindered test performance for low-performing students. We discuss the findings' potential impact on test development with universal design.