Deficits in Sense of Body Ownership, Sensory Processing, and Temporal Perception in Schizophrenia Patients With/Without Auditory Verbal Hallucinations

Abstract

It has been claimed that individuals with schizophrenia have difficulty in self-recognition and, consequently, are unable to identify the sources of their sensory perceptions or thoughts, resulting in delusions, hallucinations, and unusual experiences of body ownership. The deficits also contribute to the enhanced rubber hand illusion (RHI; a body perception illusion, induced by synchronous visual and tactile stimulation). Evidence based on RHI paradigms is emerging that auditory information can make an impact on the sense of body ownership, which relies on the process of multisensory inputs and integration. Hence, we assumed that auditory verbal hallucinations (AVHs), as an abnormal auditory perception, could be linked with body ownership, and the RHI paradigm could be conducted in patients with AVHs to explore the underlying mechanisms. In this study, we investigated the performance of patients with/without AVHs in the RHI. We administered the RHI paradigm to 80 patients with schizophrenia (47 with AVHs and 33 without AVHs) and 36 healthy controls. We conducted the experiment under two conditions (synchronous and asynchronous) and evaluated the RHI effects by both objective and subjective measures. Both patient groups experienced the RHI more quickly and strongly than HCs. The RHI effects of patients with AVHs were significantly smaller than those of patients without AVHs. Another important finding was that patients with AVHs did not show a reduction in RHI under asynchronous conditions. These results emphasize the disturbances of the sense of body ownership in schizophrenia patients with/without AVHs and the associations with AVHs. Furthermore, it is suggested that patients with AVHs may have multisensory processing dysfunctions and internal timing deficits.

Excitation/Inhibition imbalance increases the proneness to experience the sound-induced flash illusion by impairing multisensory causal inference in the schizophrenia spectrum

“…Individuals within this spectrum are known to have impairments in primary somatosensory functions such as tactile sensitivity 1–3 and proprioception 4,5 . Moreover, there is consistent evidence of higher-order somatosensory impairments observed in body ownership 6–9 , bodily-self boundary 10–13 and self-recognition 14,15 processes within the spectrum.…”

“…Speculatively, our predictions about multisensory causal inference impairments due to E/I imbalance could be related to bodily self-aberrations observed in the SCZ spectrum [4, 13, 15, 96]. Empirical evidence consistently shows a co-occurrence of reduced spatiotemporal discrimination and impaired body ownership indexed by a higher proneness to experience the Rubber Hand Illusion (RHI) in the SCZ spectrum [6–9]. We tentatively suggest that a stronger prior of sensory stimuli (visual and tactile) coming from a common source produced by an imbalance of E/I in multisensory integration networks increases susceptibility to RHI and bodily perceptual symptoms observed in the SCZ spectrum [9, 97, 98].…”

“…Empirical evidence consistently shows a co-occurrence of reduced spatiotemporal discrimination and impaired body ownership indexed by a higher proneness to experience the Rubber Hand Illusion (RHI) in the SCZ spectrum [6][7][8][9] . We tentatively suggest that a stronger prior of sensory stimuli (visual and tactile) coming from a common source produced by an imbalance of E/I in multisensory integration networks E/I imbalance increases the proneness to experience the sound-induced flash illusion by impairing multisensory causal inference in the schizophrenia spectrum 20 increases susceptibility to RHI and bodily perceptual symptoms observed in the SCZ spectrum 9,97,98 .…”

“…Individuals within this spectrum are known to have impairments in primary somatosensory functions such as tactile sensitivity [1][2][3] and proprioception [4,5]. Moreover, there is consistent evidence of higher-order somatosensory impairments observed in body ownership [6][7][8][9], bodily-self boundary [10][11][12][13] and self-recognition [14,15] processes within the spectrum. E/I imbalance impairs multisensory causal inference by increasing the proneness to experience the sound-induced flash illusion in the schizophrenia spectrum 3…”

Reduced learning rate and E/I imbalance drive Peripersonal Space boundaries expansion in Schizophrenia

“…Unusual PPS representations have been theoretically linked to bodily self-aberrations in the SCZ spectrum [20,25,79]. According to this view, weaker or unstable PPS representations observed in patients could be behind the higher proneness to experience bodily self-illusory phenomena, such as the observed in the Rubber Hand [30,36,80,81],…”