What vestibular constraint is not.
You can name the four signals. The next discipline is keeping them separate from the domains they most often get confused with.
Nine neurodevelopmental domains produce behavioral signals that overlap in their surface presentation. A vestibular constraint can look proprioceptive. A frontal executive constraint can look vestibular. A vestibular constraint can look like non-compliance. These misidentifications follow predictable patterns. This unit trains the discriminating observations that separate them.
Vestibular vs. Proprioceptive
The student who seeks postural support at the desk edge AND applies heavy pressure when writing is expressing both vestibular and proprioceptive signals simultaneously. The vestibular signal is the postural seeking. The proprioceptive signal is the pressure modulation. They co-occur. Rate each in its own domain. Do not collapse one into the other because they appear together.
Discriminating question
Is the behavior about the body's relationship to the environment and gravity? Vestibular. Is it about the force and position of body parts relative to each other? Proprioceptive.
Vestibular vs. Frontal Executive
The student whose threshold pauses create delays in task initiation appears to have a frontal executive constraint. The discriminating observation is context-specificity. Frontal initiation delays appear across all demand types regardless of movement context. Vestibular threshold delays appear specifically at points of postural transition.
Discriminating question
Does the initiation difficulty occur across all task types, or primarily at transition moments involving movement or spatial change? All types: Frontal. Transitions specifically: Vestibular.
Vestibular vs. Behavioral Non-Compliance
The student whose angular acceleration avoidance is read as non-compliance is the most clinically consequential misidentification in this domain. The behavioral intervention that follows requires the student to attempt the demand that her system cannot manage. She becomes dysregulated. The dysregulation is documented. The vestibular constraint remains unaddressed.
Discriminating question
Is the avoidance specific to activities involving rapid head position change, spinning, or spatial disorientation? If yes: vestibular. If the avoidance is general across demand types: consider frontal or limbic-prefrontal.