Influence of sensory loss on the perception of verticality in stroke patients

Purpose: The aim of this study was to investigate the relationship between somatosensory loss and perception of verticality in stroke patients suffering single-hemisphere lesions. Method: Somatosensory loss was measured using the Rivermead Assessment for Somatosensory Performance (RASP). Perception of verticality was assessed with the Subjective Visual Vertical (SVV) and the Subjective Postural Vertical (SPV) tests. Absolute Values of SVV and SPV were used to analyze the amount of deviation in relation to somatosensory loss. Results: Thirty-two patients were included in the study (mean age = 45.91 SD = 31.88 years). Analysis showed that somatosensory loss was related to results of the SVV (r = -0.552, p = 0.001, Pearson Rank) and the SPV (r = -0.661, p < 0.001, Spearman.). Furthermore, results showed that both joint-related (SVV: r = -0.411, p = 0.019, Pearson Rank; SPV: r = -0.597, p = 0.001, Spearman.) and skin-related (SVV: r = -0.595, p < 0.001, Pearson Rank; SPV: r = -0.663, p < 0.001, Spearman rho) somatosensory information is related to verticality perception. Conclusions: This study provides evidence that perception of verticality is related to somatosensory loss, which means that somatosensory loss will lead to a larger amount of deviation of SVV and SPV in relation to the gravitational vector. Furthermore, it is interesting to note that both SVV and SPV are influenced by somatosensory loss.