Re:Eye tracking Deficit

[Guest guest]

Issues of convergence are primarily a lesion of the 4th

cranial nerve, the Trochlear Nerve, which activates the medial rectus muscle

and originates from the contralateral Pons. You mention that there is lack of

convergence and excessive convergence. I assume that this means one eye does

not converge well and the other converges too much or too rapidly. This would

strike me as a cerebellar issue. You could check some basic cerebellar

functions (increased or decreased postural sway with eyes closed, they will

fall to their cerebellar lesion, eyes closed finger-to-nose test, watch for

inaccuracy, stopping short and hitting the nose too hard [hypometria and hypermetria

respectively]) to identify a cerebellar lesion and then have them work with a

Chiropractic neurologist, occupational therapist, or physical therapist for

tools to address a cerebellar deficit. I am not aware of any way to target the

cerebellum with NFB but would love to hear about it if anyone knows a way to do

so.

As far as general eye movements, the parietal lobe drives

pursuits (slowly following a moving object or moving the eyes L to R with

reading), the frontal lobe initiates a saccade (quickly drawing the eye to a

particular target such as going to the beginning of the next line of text) and

the opposite cerebellum stops the saccade at the exact right spot. So, to read,

the L parietal lobe pushes the eyes to the R and the L frontal lobe pulls them

back to the L and the R cerebellum stops the eyes in exactly the right spot.

Ascertaining more specifically what his or her eye tracking problem is can help

guide where you might want to train or if you need to refer them to someone that

can deal with cerebellar issues more directly.

The cerebellum’s biggest source of input is the mechanoreceptors

in the spinal joints and the muscle spindles of the postural muscles so

Chiropractic care is probably the biggest benefit to a cerebellar problem.

Adjusting the spine on the side of the cerebellar deficit only will create some

neuroplastic changes in that side of the cerebellum.

Pete mentioned in one of his training modules that the Delta

rhythm originates from the brainstem. I wonder if there is any type of training

of the Delta rhythm that can change brainstem function.

Steve Ranicki, DC