Is ADHD a Left or Right Brain Imbalance? A Neuro-Optometric Perspective
When we think of ADHD, most people picture attention challenges, distractibility, or impulsivity. But beneath those surface behaviors lies a complex story of how different parts of the brain work — or don’t work — together.
Emerging neuroscience and developmental models, including the work of Dr. Robert Melillo, suggest that ADHD may involve more than a “chemical imbalance.” It may also reflect an imbalance between the brain’s two hemispheres — a left-right developmental mismatch that influences attention, motor control, and sensory regulation.
Two Sides of the Same Brain
The human brain is beautifully lateralized.
- The left hemisphere specializes in detail, language, sequencing, and goal-directed action.
- The right hemisphere supports big-picture awareness, spatial orientation, emotional attunement, and sustained attention.
When both sides mature and communicate efficiently, we experience balance — in focus, movement, and emotion. When one side develops faster than the other, that harmony is disrupted.
What Research Shows
Modern brain imaging consistently finds that people with ADHD tend to show reduced activation in the right hemisphere, particularly in areas responsible for sustained attention, spatial awareness, and inhibition.
These include the:
- Right prefrontal cortex — focus and impulse control
- Right parietal lobe — spatial and sensory awareness
- Right cerebellum and basal ganglia — timing, rhythm, motor control
At the same time, the left hemisphere — which drives language and action — may remain relatively dominant. The result? A brain that is quick to act but slower to sustain, reflect, and regulate.
Melillo’s Developmental Imbalance Theory
Dr. Robert Melillo’s “Functional Disconnection Syndrome” builds on this idea. He proposes that ADHD arises from a delay in right-hemisphere maturation during early childhood. If primitive reflexes remain active (for example, Moro or ATNR reflexes) or early motor milestones were delayed, one side of the brain may not fully integrate.
- Right-hemisphere delay → difficulties with attention, spatial awareness, and emotional regulation.
- Left-hemisphere dominance → fast language, impulsivity, and hyperactivity.
- Combined type ADHD → inconsistent switching between the two, with poor timing and coordination.
This model shifts our focus from “chemical imbalance” to developmental imbalance, emphasizing how movement, vision, and sensory experiences shape the growing brain.
Why This Matters in Vision and Neuro-Optometric Care
The right hemisphere plays a crucial role in visual-spatial awareness, body orientation, and peripheral vision — all essential for efficient learning and attention.
When it’s underactive, children and adults may experience:
- Trouble staying visually engaged or “anchored”
- Poor eye-hand coordination
- Postural asymmetry or right-sided drift
- Overreliance on verbal/analytical strategies
- Fatigue with reading or near work
Through targeted neuro-optometric rehabilitation, reflex integration, and sensory-motor activities, we can help re-balance hemispheric activation. When visual, vestibular, and proprioceptive systems synchronize, the brain finds its rhythm again.
Integrating Both Perspectives
Mainstream neuroscience and developmental theories are not opposites — they’re complementary. Both recognize that ADHD involves network dysregulation, especially within the right-sided attention circuits and their communication across the corpus callosum.
By addressing how the eyes, body, and brain coordinate, we can bridge these perspectives into a practical, empowering approach to care.
Our Approach at A-Ha Vision
At A-Ha Vision Neuro-Optometric Rehabilitation Clinic, we look beyond labels. We help each patient strengthen their own neural balance — through vision therapy, movement, light, and sensory integration — so that the brain’s natural potential for focus, calm, and connection can emerge.
ADHD isn’t just about focus — it’s about how the brain connects. And connection is something we can nurture.
Next Step
Curious whether a hemispheric imbalance might be influencing your child’s attention or learning?
Contact us to schedule a Functional Vision and Neuromotor Evaluation.
