OBJECTIVES: In this study we investigated the effect of polarity-related differences in short-duration very low-intensity galvanic vestibular stimulation (GVS), not perceived by the subject, by evaluating the minimal postural sway responses in healthy people. We also verified its possible usefulness as a differential diagnostic tool in patients with postural instability disturbances related to polyneuropathy or peripheral vertigo. METHODS: We applied bimastoid opposite polarity direct current GVS (0.7 mA for 1 s) and recorded the induced postural response with an electromagnetic head position tracker. Latency, amplitude, velocity and an asymmetry index were measured between two reverse polarity sessions. RESULTS: The postural response was easily recorded and was statistically wider in amplitude and velocity in the polyneuropathy group than in the other groups. Postural responses were asymmetric only in the group with mild peripheral vertigo. CONCLUSION: These findings suggest that even weak GVS affects vestibular excitability: cathodal polarization increases whereas anodal GVS decreases excitability. Symmetry and amplitude or velocity of the postural responses, particularly in the eyes closed condition, can differentiate the three groups of subjects tested.
OBJECTIVES: In this study we investigated the effect of polarity-related differences in short-duration very low-intensity galvanic vestibular stimulation (GVS), not perceived by the subject, by evaluating the minimal postural sway responses in healthy people. We also verified its possible usefulness as a differential diagnostic tool in patients with postural instability disturbances related to polyneuropathy or peripheral vertigo. METHODS: We applied bimastoid opposite polarity direct current GVS (0.7 mA for 1 s) and recorded the induced postural response with an electromagnetic head position tracker. Latency, amplitude, velocity and an asymmetry index were measured between two reverse polarity sessions. RESULTS: The postural response was easily recorded and was statistically wider in amplitude and velocity in the polyneuropathy group than in the other groups. Postural responses were asymmetric only in the group with mild peripheral vertigo. CONCLUSION: These findings suggest that even weak GVS affects vestibular excitability: cathodal polarization increases whereas anodal GVS decreases excitability. Symmetry and amplitude or velocity of the postural responses, particularly in the eyes closed condition, can differentiate the three groups of subjects tested.
Authors: Steno Rinalduzzi; Carlo Trompetto; Lucio Marinelli; Alessia Alibardi; Paolo Missori; Francesco Fattapposta; Francesco Pierelli; Antonio Currà Journal: Biomed Res Int Date: 2015-01-14 Impact factor: 3.411
Authors: Steno Rinalduzzi; Marco Serafini; Marco Capozza; Neri Accornero; Paolo Missori; Carlo Trompetto; Francesco Fattapposta; Antonio Currà Journal: PLoS One Date: 2016-03-15 Impact factor: 3.240