Multisensory remission of somatoparaphrenic delusion

Abstract

SummaryThis study investigates whether the rubber hand illusion (RHI) can induce a remission of somatoparaphrenia, a somatic delusion usually following righthemisphere damage, which typically manifests as a defective sense of ownership of one's contralesional body parts. First, we show that patients with somatoparaphrenia can experience a reliable RHI, exhibiting illusory effects similar to those reported by healthy participants. Moreover, synchronous touches applied to the patients' visible disowned left hand (rather than to the rubber hand), and to their right invisible unimpaired hand, induce an immediate self-attribution of the disowned hand, without affecting other sensorimotor or attentional disorders. The higher-level representation of the body concerned with ownership, deranged as a somatic delusion in patients with somatoparaphrenia, is penetrable, and can be restored by multisensory stimulations.

Vestibular contributions to a right-hemisphere network for bodily awareness: Combining galvanic vestibular stimulation and the “Rubber Hand Illusion”

“…Bisiach et al (1991) explained vestibular modulation of somatoparaphrenia as an enhancement in attentional mechanisms that restored spatial representation of the body (Bisiach et al, 1991). However, it has been recently reported that multisensory stimulation can lead to remission from somatoparaphrenia, without affecting concomitant attentional disorders, suggesting a dissociation between attentional mechanisms and bodily awareness (Bolognini et al, 2014). Our results are coherent with this dissociation between attention and bodily awareness.…”

Right insular damage decreases heartbeat awareness and alters cardio-visual effects on bodily self-consciousness

“…crawford/pages/dept/psychom.htm#conflims. See a similar use of the Crawford test in Bolognini et al, 2014). The software tests whether an individual's score is significantly different from a control/normative sample and provides a point estimate of the rarity/abnormality of the score; namely, it estimates the percentage of the population that would obtain a lower score.…”

Illusory hand ownership in a patient with personal neglect for the upper limb, but no somatoparaphenia

“…The RHI elicited by visuo‐tactile stimulation has been previously tested in right‐brain‐damaged patients, but these investigations mainly focused on the presence of explicit disownership for body parts such as somatoparaphrenia. Thus, previous data show that somatoparaphrenic patients suffering right‐brain lesions are more susceptible to integrate a left fake hand after both synchronous and asynchronous visuo‐tactile stimulation (van Stralen et al ., ) and that the RHI can be administered to induce the selective remission of the delusional disownership concerning the affected left hand (Bolognini et al ., ). A recent study has also examined the role of motor impairments in the sense of hand ownership testing a group of right‐brain‐damaged patients with hemiplegia (without proprioceptive and tactile deficits), testing the RHI for the right and left hand (Burin et al ., ).…”

“…No signs of somatoparaphrenia were detected during the neuropsychological evaluation: The feeling of disownership and ownership misattribution was investigated with a standardized interview regarding three body districts (hand, arm, and leg), and done both for the left and the right sides of the body (i.e., the right ones as control sites). The examiner pointed at the body part without touching it and asked the patient: ‘Who is this… hand/arm/leg ?’ (Bolognini, Ronchi, Casati, Fortis, & Vallar, ; Vallar & Ronchi, ). In addition to the standardized interview, no somatoparaphrenia was detected during daily clinical sessions (e.g., during therapies).…”