Assesment of vestibulo-ocular system by video head impuls test in chronic inflammatory demielynating polyneuropathy

Objective: Vestibular impairment has been shown in some of the polyneuropahty patients and it was suggested that it may worsen the imbalance. In this study, we aimed to investigate the vestibuloocular reflex (VOR) with video head impulse testing in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Our second aim is to show the effect of vestibular impairment on balance and gait in CIDP patients. Method: There were 24 CIDP patients and no controls in the study. Balance was tested by Berg Balance Scale, Dynamic gait index, Fall efficacy scale and Clinical test of sensory interaction on balance. Six patients could not do test due to severe imbalance. VOR was tested by video head impulse (vHIT) googles (OtosuiteV, GN, Otometrics, Denmark) which investigates 3 semicircular canals with 5-10 angles and with a speed of 750-600der/sec head impulses. Spearman and Kendall's correlation analysis were used in clinical signs, scales and variables for statistics. Results: There were 17 male (70.8 %) and 7 female (29.2%) with a mean age of 53.9±14.1 years and age range (26-83 years). There was significantly positive correlation between disease duration and foam head back eyes open, head rotated right and eyes open, head rotated left eyes open and closed(p<0,05). There was a significant correlation between foam head back eyes open and closed Berg Balance scale, Dynamic gait index, Fall efficacy scale. Firm and foam head back, eyes open, eyes closed right and left rotated were siginificantly correlated. vHIT showed bilateral vestibular loss in 8 patients, 8 patients had VOR gain loss without catch up saccades, 6 patients had normal VOR and gain. Duration of disease was significantly different with the right lower sensory response in Kruskal –Wallis test (p= 0,044). Conclusion: Our study showed that 8 patients had bilateral vestibular loss which was documented by the vHIT testing in 3 different semicircular canals. Vestibular testing was not routine examination in patients with polyneuropathy. After showing the involvement of vestibular system in CIDP patients, we like to suggest that at least head impulse test should take a place in routine examination in these patients. Additional effect of vestibular impairment to imbalance is unquestionable in CIDP patients, vestibular rehabilitaion should be considered in these patients. Lastly, it is very important to follow patients who had low VOR gain without catch up saccades or normal gain longitudinally in order to show the possible vestibular impairment in CIDP. Key words: CIDP, video head impulse , vestibular impairment, balance