In the world of somatic education and yoga therapy, we often talk about Sensory Motor Amnesia (SMA)—a term coined by Thomas Hanna to describe the way parts of our body “go offline” after stress, trauma, injury, or long-term postural habits. But what’s really happening beneath the surface? And how does this concept map onto what modern neuroscience tells us? Let’s explore.
WHAT IS SENSORY MOTOR AMNESIA?
SMA refers to a ‘loss of voluntary control and awareness of certain muscles‘, particularly the postural muscles that should work reflexively to support our movement. This isn’t paralysis—it’s more subtle. It’s the body forgetting how to move with ease and the brain losing accurate sensory feedback about those forgotten areas.
This is often seen in:
- People with chronic pain or tension
- Repetitive stress injuries or postural collapse
- Trauma survivors who have dissociated from parts of their body
- High-functioning individuals under prolonged stress
In somatic-based practice, we use slow, mindful movements to re-educate the brain and restore communication between body and mind. This is how we move from amnesia to integration—from disconnection to embodied presence.
THE NEUROSCIENCE BEHIND IT: CORTICAL INHIBITION AND SMUDGING
While SMA comes from somatic education, similar phenomena have been documented in neuroscience under different names:
CORTICAL INHIBITION
- Refers to the brain’s suppression of motor activity in specific muscles or regions.
- It is often caused by chronic pain, trauma, disuse, or prolonged stress.
- It results in the inability to fully access or voluntarily control parts of the body – echoing SMA almost exactly.
CORTICAL SMUDGING
- A term used in pain neuroscience (especially by researchers like Lorimer Moseley).
- It describes a blurring of the brain’s sensory map in the somatosensory cortex.
- It leads to poor sensory awareness and motor control – your brain literally doesn’t have a clear picture of that part of the body anymore.
DISRUPTED SENSORIMOTOR INTEGRATION
At the core of both SMA and its scientific cousins is the concept of disrupted sensorimotor integration: the loop between sensation (input) and movement (output) gets distorted. The brain isn’t accurately receiving or interpreting messages from the body, and as a result, movement becomes inefficient, uncoordinated, or missing altogether.
This can present as:
- One side of the body feeling “dead” or overactive
- Difficulty finding stability or grounding
- A lack of proprioception (body-in-space awareness)
FROM DISCONNECTION TO INTEGRATION
In a world that encourages speed, output, and tension, disconnection from the body is almost inevitable. But reconnection is possible. And it doesn’t require force – it requires listening.
The journey from Sensory Motor Amnesia to integration is, in essence, a journey back to the felt sense of self. It’s where somatics, neuroscience, and healing meet.
WHY IT MATTERS FOR YOGA THERAPY AND SOMATIC EDUCATION
Whether we use somatic movement, yoga therapy, or neuromuscular techniques, the aim is the same: to restore awareness and coordination. We re-pattern the brain-body loop through slow, refined movement, breath, and attention. We teach the nervous system how to listen again, how to update its maps, and how to move toward wholeness.
By bridging the language of SMA with the neuroscience of cortical inhibition and sensorimotor integration, we not only affirm the wisdom of somatic traditions – we give our students, clients, and peers a common language that validates both experience and science.
