P35. Neglect and vestibular failure – Spatial or attentional deficit?

Abstract

Objectives Acute peripheral vestibular failure (VF) and neglect show similarities in clinical presentation and neglect can be ameliorated by vestibular stimulation. Furthermore, cortical areas involved in neglect patients overlap in part with the multisensory cortical vestibular network ( Karnath and Dieterich, 2006 ). Thus, the question did arise whether acute VF can induce spatial neglect. The aim of the current study was to find out whether patients with an acute VF show spatial neglect and if test scores were related to the severity of the deficit. Methods 28 patients with acute VF were assessed for signs of vestibular deficits and spatial neglect clinically as well as with common standard paper pencil neglect testing (bells test ( Gauthier et al., 1989 ), Albert’s test ( Albert, 1973 ), line bisection task ( Schenkenberg et al., 1980 ), figure copying). The laterality in the cancellation tasks was further analyzed using the Center of Cancellation method (CoC) ( Rorden and Karnath, 2010 ). The deficit was correlated with deviation of subjective visual vertical (SVV) and the degree of canal paresis. Results All patients had clear peripheral vestibular deficit at the time of testing. Mean time from symptom onset to neglect testing was 1.8 days (SD 1.7 d), to SVV testing 1.9 days (SD 1.8 d, mean deviation ± 7.3°) and to caloric testing 2.3 days (SD 2.3, mean reduction of caloric excitability 51%). Three patients showed pathologic scores in neglect tests (10%), two contralesionally and one ipsilesionally. One of these patients had a score fulfilling the criteria for spatial neglect in the bells test ( Gauthier et al., 1989 ) but not in the CoC method ( Rorden and Karnath, 2010 ). In contrast, the patient with a pathological CoC score did not meet the criteria for spatial neglect using the original method. One patient omitted one line in the Albert’s test contralaterally. Only one patient had pathological test scores in two tests but deviations in line bisection were both ipsilateral and contralateral. No patient showed congruent bias to one side in two different tests or analysis methods. There was no significant correlation between the total number of omissions in the bells test and the magnitude of SVV deviation or canal paresis. A group wise comparison of patients with and without pathological scores was carried out but the effect size was not strong enough to produce reliable results due to the small number of three patients. Conclusions VF patients occasionally showed pathological scores on single and different neglect tests. No correlation was found between omissions and SVV deviation or canal paresis. The three patients with pathologic scores did not show neglect behavior and the pattern of omissions is far less pronounced in the patients with VF compared to neglect patients. Thus, we suggest that these findings represent an attentional deficit and that novel tools to assess this deficit are needed. These should take spatial exploration and attention in a three-dimensional space into account to differentiate an attentional from a true spatial deficit. Acknowledgements This study was supported by the German Federal Ministry of Education and Research (BMBF, grant code 01 EO 0901) and the German Foundation for Neurology to MD.