What is Comprehensive Motor and Sensory Assessment for Special Needs?
A comprehensive motor and sensory assessment for special needs are diagnostic tests conducted in children with special needs who have ophthalmologic conditions. Special needs children can be defined as ones with neuromotor disorders such as autism and down’s syndrome.
Role of Comprehensive Motor and Sensory Assessment in Special Needs
As the eye is an extension of the brain, motor and sensory assessment (neurologic exams) becomes a crucial diagnostic tool. The assessment helps to evaluate and determine the degree of a patient’s ocular findings such as cranial neuropathies, visual field defects, optic neuropathy, double vision, pupillary defects, strabismus (deviating eyes), and loss of vision. The assessment also helps to confirm the suspicion of underlying etiologies such as stroke, demyelinating disease, space-occupying lesion, and many others.
Common Motor and Sensory Problems Associated with Special Needs
Some of the common sensorimotor difficulties experienced by special needs children with visual impairment include trouble with perception of their surroundings; postural problems and trouble with gait acquisition; changes in spatial orientation; trouble with coordinating perceptual information and its adjustment to external reality; and delay in acquisition of functional habits, such as eating and dressing.
Comprehensive Motor and Sensory Assessment
The following motor tests are employed to detect misalignment and deviating eyes and include:
- Hirschberg (H) Test: This test is also known as a corneal reflex test and is a simple and swift way to check for ocular alignment. This test is especially useful for children born with strabismus, poor vision, and who are not able to track well or fixate.
- Krimsky (K) Test: This is a test to measure the level of misalignment of the two eyes and is a reference test to diagnose strabismus. The test employs a prism before the fixating eye until the reflection is similarly positioned in both eyes to quantitate deviation.
- Cover-Uncover Testing: This test is employed on children who have a deviation and are capable of fixating near and distant targets. A cover-uncover test is able to pick up slight manifest deviations that are always present. A cover test confirms whether or not the eyes are straight.
- Alternate Cover Testing: This is a test performed to pick up any latent deviation on top of the manifest deviation. In this test, your physician occludes one eye and then the other, switching the eye occluder back and forth to occlude the eyes without allowing the child to fuse in between occlusion. The alternate cover test is the most dissociative cover test and quantifies a total deviation, including the tropic plus the latent/phoric component.
The following sensory tests help determine the binocularity and fusional status of the child. These tests may include:
- Randot or Titmus tests: These tests are most commonly employed to measure stereopsis (depth perception), as well as detect abnormal retinal correspondence (ARC). The degree of dissociation is moderate. This test can be utilized as a quick screening to find out if the child is utilizing their two eyes together.
- Base Out Test: The main indication for this test is to detect the presence of small central suppression scotoma (blind spot that obstructs a part of the vision). The degree of dissociation is mild. This test can be utilized with children who have reduced depth perception while orthophoric on cover testing, small to intermediate angle deviations, and monofixation syndrome.
- Double Maddox Rod: This test is utilized to find out the presence of a cyclodeviation. This test is extremely dissociating. The test is specifically useful to be employed on children with suspected thyroid eye disease or fourth nerve palsy.
- Worth 4 Dot: The objective of this test is to detect foveal suppression and peripheral sensory fusion. The degree of dissociation is high. This test can be employed for any verbal child with any angle of strabismus particularly with decreased stereopsis.
- Bagolini Glasses: This is a test employed to determine the direction of a pseudofovea (an intact eccentric part of the retina), ARC, and suppression. This test also indicates to the examiner if the child has periphery-sensory fusion. This test is mildly dissociating so it helps to detect small ARC even in large-angle strabismus.