After a concussion, lights and sounds often feel overwhelming because the brain’s ability to process sensory information is disrupted. Normally, the brain acts like a conductor, coordinating various sensory inputs—such as sight and sound—so they feel balanced and manageable. When a concussion occurs, this coordination is impaired, making everyday stimuli seem much sharper, louder, or more intense than before. This condition is known as sensory overload.
The brain injury affects how different sensory systems communicate and work together. For example, the visual system may struggle to track moving lights or adjust to changes in brightness, causing eye strain or dizziness. Similarly, the auditory system may become hypersensitive, making normal sounds feel too loud or jarring. This happens because the brain’s filtering mechanisms, which usually help ignore unnecessary or repetitive stimuli, are not functioning properly after the injury. As a result, even familiar environments with typical levels of light and sound can feel overwhelming and exhausting.
Additionally, the brain’s repair cells, called microglia, become activated after a concussion, leading to inflammation. This inflammation can further disrupt normal brain function, including sensory processing. Neurons may also receive less oxygen and nutrients, which can worsen symptoms and prolong recovery.
Sensory overload is closely linked to neurofatigue, a state of mental exhaustion common after brain injury. Neurofatigue can both cause and result from sensory overload, creating a cycle where the brain becomes increasingly sensitive to stimuli and tires more easily. This means that people with sensory overload often experience fatigue and need longer recovery times after exposure to bright lights or loud sounds.
Because of these changes, people recovering from a concussion may find that holiday lights, music, or crowded places feel particularly intense and uncomfortable. Rehabilitation therapies that focus on improving sensory integration and brain coordination can help reduce these symptoms over time, allowing the brain to better manage sensory input again.
Sources
https://www.plasticitycenters.com/blog/holiday-lights-and-music-after-brain-injury
https://www.braininjury-explanation.com/coping/dealing-with-neurofatigue
https://www.anewchiroclinic.com/blog/concussions
https://smart.dhgate.com/why-are-concussions-bad-understanding-the-risks-long-term-effects/
