Individual differences in lateralisation of hallucinations associated with sleep paralysis

Area of Science:

• Neuroscience
• Sleep Medicine
• Psychology

Background:

• Sleep paralysis is often accompanied by vivid hallucinations.
• Hallucinations during sleep paralysis can be categorized into vestibular-motor (V-M) and intruder types.
• Individual differences in hallucination experiences are not well understood.

Purpose of the Study:

• To investigate individual differences in the lateralization of V-M and intruder hallucinations.
• To explore the association between limb preferences (handedness and footedness) and hallucination lateralization.
• To test the hypothesis that V-M hallucinations stem from a bodily-self neuromatrix, while intruder hallucinations involve a threat-activated vigilance system.

Main Methods:

• A web-based survey was administered to 201 participants experiencing sleep paralysis.
• Participants reported on their experiences with V-M and intruder hallucinations.
• Handedness, footedness, and the lateralization of hallucinations were assessed.

Main Results:

• Vestibular-motor (V-M) hallucinations showed a significant positive association with limb preferences.
• Intruder hallucinations did not show a significant association with handedness or footedness.
• These findings support the hypothesis of distinct neural origins for V-M and intruder hallucinations.

Conclusions:

• Limb preferences are associated with the lateralization of V-M hallucinations during sleep paralysis.
• The findings suggest that V-M hallucinations may arise from the activation of sensorimotor and vestibular systems.
• Intruder hallucinations appear to be independent of limb lateralization, possibly linked to different neural pathways.