Diagnostic Testing Part II

After much anticipation I finally had my follow-up and received the results of my diagnostic tests: Electronystagmography (ENG) and Vestibular Evoked Myogenic Potentials (VEMPs).

If you're interested in hearing what my exam entailed, this website entitled, Evaluation of Vestibular Function describes it perfectly, along with why each test is used. Just scroll down toward the middle, where it reads, "Vestibular Laboratory Tests."

The only abnormal results discovered were through caloric testing. As the website above describes:

This is the only vestibular test that stimulates one side of the vestibular system at a time. In this test, patients are placed in a 30 degree from prone position to allow the horizontal semicircular canal to be in a vertical orientation. Warm and cold water or air is then flushed into the external auditory canal at 7 degrees above or below body temperature. Varying temperature causes a non-physiologic stimulation of one labyrinth that may evoke vertigo, nystagmus, and occasionally nausea and vomiting. Warm water for example causes the perilymph to rotate towards the ampula, resulting in stimulation of the ipsilateral labyrinth and a drift of the eyes away from the stimulated side. The eyes compensate with a saccade toward the stimulated side. The opposite occurs with cold water stimulation. The mnemonic COWS is used to remember the direction of nystagmus (Cold Opposite Warm Same). Ice water irrigations can be used if milder stimulation does not result in nystagmus. Because caloric irrigation results in stimulation analogous to head movements of 0.002 to 0.004 Hz, significant vestibular asymmetry can exist in the presence of normal caloric responses as real-life head movements are in the 1 to 6 Hz range. Visual fixation should reduce the strength of caloric responses in the presence of normal CNS function. Failure to suppress nystagmus 50-70% with visual fixation is abnormal.

My results:
This video nystagmogram (VNG) was abnormal. This VNG showed no spontaneous, gaze, or positional nystagmus. Saccade testing showed normal latencies, velocities and accuracies. Smooth pursuit and optokinetic tests were normal and symmetrical. The Dix-Hallpike test for benign paroxysmal positional vertigo (BPPV) was negative for both sides. Bithermal caloric irrigations were remarkable for a 56% Left unilateral weakness. Caloric fixation suppression was normal. Caloric testing suggests a peripheral vestibular lesion on the left side.

There's no official diagnosis of Vestibular Migraine, but I only saw the Physician's Assistant during the follow-up. She believes, along with my PT, that the Vestibular Rehabilitation exercises will help my inner ear issues. And if this vestibular lesion is exacerbating my Chronic Migraines, let's hope healing one will minimize the other.

I appreciate you all taking this journey with me, and I'll keep you posted on my progress.