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[Virtual dystonia due to posterior ventrolateral thalamic infarct: case report]
R de Oliveira-Souza1, M E Martins, P A Andreiuolo
1Clínica Médica III, Hospital Universitário Gaffrée Guinle (HUGG, UNI-RIO), Brasil.
Arquivos De Neuro-Psiquiatria
|September 1, 1996
Summary
A thalamic infarct caused a patient to experience painful toe cramping, a phantom dystonia. This sensory illusion resolved with pressure, highlighting how brain lesions can create false bodily sensations.
Area of Science:
- Neuroscience
- Neurology
- Sensory processing
Background:
- Phantom sensations and purely mental movements can occur without outward motor signs.
- The Dejerine-Roussy syndrome involves thalamic lesions causing sensory disturbances.
Observation:
- A 43-year-old man with diabetes and hypertension developed Dejerine-Roussy syndrome with illusory toe cramping.
- The cramping sensation occurred when lying down or lifting the foot and resolved with pressure.
- Severe proprioceptive loss was noted in the affected toes, despite intact superficial sensation.
Findings:
- MRI revealed a posteroventrolateral thalamus (VPL) lesion with thalamo-cortical degeneration.
- SPECT showed thalamic hypoperfusion, ipsilateral parietal cortex, and bilateral basal ganglia hypoperfusion.
- The findings suggest a disconnection between the somatic sensory cortex (S-1) and proprioceptive input.
Implications:
- This case illustrates how thalamic lesions can lead to "autochthonous" (self-generated) sensory experiences.
- It highlights the role of proprioception in maintaining accurate body representation.
- Understanding these mechanisms is crucial for diagnosing and treating complex sensory disorders.