New method for induction and real-time assessment of hallucinations

© 2022 EPFL

© 2022 EPFL

Fosco Bernasconi and colleagues report in a new paper, published in Nature Protocols, a new robotic method and procedure allowing to induce and investigate specific hallucinations that affect patients with Parkinson’s disease, Dementia with Lewy bodies or schizophrenia.

Although hallucinations are important and frequent symptoms in major psychiatric and neurological diseases, little is known about their brain mechanisms. Hallucinations are unpredictable and private experiences, making their investigation, quantification and assessment highly challenging. A major shortcoming in hallucination research is the absence of methods able to induce specific hallucinations, which resemble clinical hallucinations, can be elicited repeatedly and vary across experimental conditions. By integrating clinical observations and recent advances in cognitive neuroscience with robotics, we have designed a novel device and sensorimotor method able to repeatedly induce a specific, clinically relevant hallucination: presence hallucination. Presence hallucinations are induced by applying specific conflicting (spatiotemporal) sensorimotor stimulation between an upper extremity and the torso of the participant. Another, MRI-compatible, robotic device using similar sensorimotor stimulation permitted the identification of the brain mechanisms of these specific and clinically-relevant hallucinations, affecting many patients suffering from Parkinson’s disease, Dementia with Lewy bodies or schizophrenia. The method has already been applied to patients with schizophrenia (Salomon et al., 2020), patients with Parkinson’s disease (Bernasconi et al., 2021), and patients with Dementia with Lewy bodies (Nicastro et al., 2021).

In the latest report we provide detailed instructions to scientists and clinicians who wish to use our robotic system in their experimental and clinical settings. We suggest that the adaptation and further integration of this robotic procedure to other psychophysical, neuropsychological, clinical and neuroimaging techniques may help early detection of patients (e.g. Parkinson’s disease, dementia with Lewy bodies) at higher risk of psychosis and related cognitive decline.


This research was supported by two generous donors advised by CARIGEST  SA (Fondazione Teofilo Rossi di Montelera e di Premuda and a second one  wishing to remain anonymous) to O.B., Parkinson Suisse to O.B,  Bertarelli Novartis Foundation for Medical-Biological Research  Foundation to O.B., Empiris Foundation to O.B., Swiss National Science  Foundation to O.B. Grant-in-Aid for Scientific Research (B) (19H04187)  of the Japan Society for the Promotion of Science to M.H. Grant-in-Aid  for Scientific Research (A) (22H00526) of the Japan Society for the  Promotion of Science to M.H. E.B. is supported by The National Center of  Competence in Research (NCCR) ‘Synapsy—The Synaptic Bases of Mental  Diseases’ (# 51AU40–125759) to O.B.


Bernasconi, F., Blondiaux, E., Potheegadoo, J., Stripeikyte, G., Pagonabarraga, J., Bejr-Kasem, H., Bassolino, M., Akselrod, M., Martinez-Horta, S., Sampedro, F., Hara, M., Horvath, J., Franza, M., Konik, S., Bereau, M., Ghika, J.-A., Burkhard, P. R., Ville, D. V. D., Faivre, N., … Blanke, O. (2021). Robot-induced hallucinations in Parkinson’s disease depend on altered sensorimotor processing in fronto-temporal network. Science Translational Medicine, 13(591).

Nicastro  N, Stripeikyte  G, Assal F, Garibotto V, Blanke O (2021). Premotor and fronto-striatal    mechanisms associated with presence hallucinations in dementia with Lewy bodies. Neuroimage Clinical. 32:102791. doi: 10.1016/j.nicl.2021.102791

Salomon, R., Progin, P., Griffa, A., Rognini, G., Do, K. Q., Conus, P., Marchesotti, S., Bernasconi, F., Hagmann, P., Serino, A., & Blanke, O. (2020). Sensorimotor Induction of Auditory Misattribution in Early Psychosis. Schizophrenia Bulletin.