VESTIBULAR DYSFUNCTION IN CHRONIC INFLAMMATORY DEMYELINATING POLYNEUROPATHY

Chronic inflammatory demyelinating polyneuropathy (CIDP) has occasiona lly been associated with clinical or laboratory evidence (magnetic res onance imaging, [MRI], visual evoked response, and brainstem auditory evoked response [BAER]) of cranial neuropathy. In most cases, the rela tionship of cranial nerve involvement to CIDP remains unclear. A 45-ye ar-old woman noted foot numbness, limb weakness, gait and postural ins tability, and oscillopsia. An IgG kappa monoclonal gammopathy of undet ermined significance was found. Bilateral vestibulopathy was documente d by clinical examination, bithermal calorics, rotary chair testing, B AERs, and dynamic posturography. MRI with gadolinium demonstrated enha ncement of cranial nerve VIII bilaterally. Over the next 6 years, the patient's relapsing and remitting course of CIDP and vestibulopathy wa s assessed by quantitative muscle and vestibular function testing (cli nically and neurophysiologically), and dynamic visual acuity. There wa s a striking synchronization between her CIDP and vestibulopathy with respect to clinical course including relapses and responses to immune therapy. The response to therapy, and evidence derived from clinical a nd laboratory investigations, suggest that the vestibular dysfunction was immune mediated.