What theoretical basis for EMDR's effectiveness involves the idea that bilateral stimulation helps the brain to process and integrate traumatic memories that were previously maladaptively stored?

The theoretical basis for EMDR's effectiveness that involves bilateral stimulation helping the brain process and integrate traumatic memories is the Adaptive Information Processing (AIP) model. This model posits that mental health symptoms, particularly those related to trauma, arise from distressing experiences that have not been fully processed and integrated into the brain's existing adaptive memory networks. When a traumatic event occurs, the brain's natural information processing system can become overwhelmed or blocked, leading to the memory being “maladaptively stored.” This means the memory remains in an isolated, fragmented, raw, and emotionally charged state, retaining the original sensations, emotions, thoughts, and physical responses from the time of the trauma, rather than being processed and filed away as a completed past event. Bilateral stimulation, which typically involves guided eye movements, alternating auditory tones, or alternating tactile sensations, is thought to activate or stimulate the brain's innate information processing system, similar to the processing that occurs naturally during Rapid Eye Movement (REM) sleep. While the individual focuses on the maladaptively stored traumatic memory, the bilateral stimulation helps to re-engage and facilitate this blocked or incomplete natural processing. This process allows the brain to make new connections, linking the previously isolated traumatic memory with more adaptive information and existing memory networks in the brain. The continuous bilateral stimulation supports the brain in desensitizing the distressing aspects of the memory and re-evaluating the associated beliefs. This leads to the “integration” of the memory, meaning it is transformed from a disturbing, emotionally charged experience into a more neutral, coherent, and resolved narrative that is stored like any other non-traumatic memory. The emotional distress decreases, and the associated negative beliefs are replaced with more positive and adaptive ones, demonstrating that the brain has successfully processed and assimilated the information.