The purpose of this qualitative retrospective case study was to measure the impact that intervention methods derived from Arwood's Neuro-Education Model had upon the learning and development of one young adult with moderate to severe developmental disabilities. One participant received the intervention methods over the course of 2 years from a single practitioner operating in a private clinic setting. Drawings, writings, and oral language samples were coded and analyzed to track how the participant evolved over time in the developmental domains of cognition, language, and social-emotional functioning. Additionally, these same artifacts were coded and analyzed to identify changes to the participant's capacity for learning, as measured by language function. At the onset of the study the participant was 16 years of age, yet functioned at levels associated with 3- to 4-year-old developmental milestones. Results demonstrated that the participant exhibited approximately 3 years of growth in language development, 2 years of growth in cognitive development, and 3 years of growth in social-emotional development during the time period studied. Similarly, results showed that the participant advanced in all measured language functions including semanticity function, referential function, productivity function, flexibility function, and displacement of ideas. These advancements were observed in multiple literacy processes including thinking, speaking, listening, reading, writing, drawing, observing, and calculating. The participant was also reported to have experienced demonstrable changes to their quality of life including greater social-emotional engagement with family members and peers at school. Though this study was not experimental by design, and thus causation could not be confirmed, the changes observed in the participant throughout this study were hypothesized to have occurred primarily due to their exposure to the Neuro-Education based methods, as these particular interventions had not been experienced by the participant prior to them initiating services at the clinic setting. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]