Pusher syndrome, formally known as contraversive pushing or lateropulsion, is a clinical disorder observed in patients following a brain injury. This condition is characterized by a severe alteration in the perception of vertical orientation, causing individuals to feel upright when they are actually tilted to one side. The disorder significantly complicates and prolongs the rehabilitation process, as patients actively resist attempts by therapists to correct their posture. Pusher syndrome affects roughly 10% of stroke survivors, and its presence is associated with a need for several additional weeks of therapy to achieve the same functional outcome level as non-pushing patients.
The Underlying Cause and Perceptual Deficit
The behavior seen in this syndrome stems from a neurological miscalculation of the body’s position relative to gravity. The problem is traced to a lesion, most commonly a stroke, affecting the posterior thalamus, the parietal lobe, or the insular cortex, often in the right hemisphere of the brain. These regions are believed to house the neural network responsible for integrating sensory input that determines upright body posture.
The core deficit is a disruption of the internal sense of verticality, known as the subjective postural vertical, not muscle weakness. Patients experience their body as “upright” when it is tilted approximately 18 to 20 degrees toward the side of their brain lesion. This sensory distortion drives the outward behavior, as the patient attempts to correct what their senses perceive as a fall toward the unaffected side. The ability to judge the vertical orientation of the surrounding visual world (subjective visual vertical) remains intact.
Identifying the Characteristic Pushing Behavior
The defining sign of the syndrome is the active, forceful use of the non-paretic (unaffected) extremities to push the body toward the hemiparetic (weaker) side. This behavior is clearly visible when the patient is sitting or standing, leading to a severe loss of balance and a high risk of falling. The patient’s push is a deliberate action, using the strong arm or leg to extend and abduct, forcefully displacing their weight laterally toward the side of their paralysis.
When a clinician attempts to gently guide the patient back to a true vertical position, the patient strongly resists, perceiving the correction as being pushed off balance. This resistance confirms the perceptual nature of the problem, as the patient genuinely believes they are defending against a fall. Standardized tools like the Scale for Contraversive Pushing (SCP) are used to formally diagnose and quantify the severity of this behavior. The SCP assesses the symmetry of the patient’s spontaneous posture, the active use of the non-paretic limbs to push, and the degree of resistance to passive correction.
Strategies for Rehabilitation and Recovery
Rehabilitation for this condition requires a specialized approach that bypasses the patient’s faulty internal perception and relies on external sensory information. The primary goal is to teach the patient to visually and tactilely re-establish their true vertical orientation. Since the patient’s visual perception of verticality is preserved, therapy leverages visual cues present in the environment.
Therapists use vertical objects like door frames, mirrors, or lines taped on the wall to provide a reference point for upright posture. Placing a mirror in front of the patient allows them to visually align their body with an objective vertical line, providing immediate feedback on their tilted position. Physical intervention focuses on blocking the pushing limb to prevent the behavior and promoting weight-bearing on the affected side.
Tactile feedback is also heavily utilized, often by having the patient sit or stand with their non-paretic side against a wall or in a corner. This contact provides a reliable external reference that confirms the actual position of their body in space. Therapists must avoid physically forcing the patient to the midline, as this triggers the strong resistance reaction. Instead, they guide the patient to actively shift their weight toward the unaffected side while maintaining contact with the external reference. While the syndrome complicates early recovery, most patients see a resolution of the pushing behavior within six months of the brain injury.