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Feeling touches in someone else's hand.
Gabriella Bottini1, Edoardo Bisiach, Roberto Sterzi
1Psychology Section, Department of Philosophy, University of Pavia, Piazza Botta 6, 27100 Pavia, Italy.
Neuroreport
|March 15, 2002
Summary
A rare neurological disorder, somatoparaphrenia, causes patients to disown limbs. In a unique case, tactile sensation in a disowned limb temporarily returned when the patient focused on another person’s touch, suggesting a shared origin for sensory and delusional deficits.
Area of Science:
- Neuroscience
- Psychiatry
- Body Perception
Background:
- Cerebral damage can lead to somatoparaphrenia, a delusion where patients disown body parts.
- This condition often co-occurs with tactile sensory loss (hemianesthesia) in the affected limb.
- Somatoparaphrenia is distinct from general delirium and points to specific neurological impairments.
Observation:
- A patient with somatoparaphrenia exhibited profound tactile imperception in her left hand.
- Remarkably, tactile sensation in the 'non-belonging' left hand improved when the patient focused on touch sensations applied to her niece's hand.
- This suggests a transient resolution of the sensory deficit through altered attentional focus.
Findings:
- The study presents a unique case linking somatoparaphrenia and tactile imperception.
- Verbal instructions to focus on another's touch transiently restored tactile perception in the disowned limb.
- This intervention suggests a temporary recomposition of the body schema by altering the sensory-attentional mismatch.
Implications:
- Both elementary sensory deficits (hemianesthesia) and complex delusional states (somatoparaphrenia) may stem from a common impairment in body image representation.
- This finding offers new insights into the neural basis of body ownership and sensory processing.
- Understanding the interplay between body schema and sensory perception could inform therapeutic strategies for neurological and psychiatric disorders.