Cortical sensory loss : is it always cortical?

Area of Science:

• Neurology
• Neuroimaging
• Stroke Medicine

Background:

• Cardioembolic stroke can lead to significant neurological deficits.
• Cortical sensory loss is typically associated with lesions in the cerebral cortex.
• Subcortical lesions are less commonly associated with primary cortical sensory deficits.

Purpose of the Study:

• To investigate the occurrence and recovery of cortical sensory loss in a patient with a subcortical cardioembolic stroke.
• To explore the relationship between cerebral blood flow, somatosensory evoked potentials (SEPs), and sensory deficits.
• To evaluate the potential role of cerebral diaschisis in subcortical stroke-induced sensory abnormalities.

Main Methods:

• Case study of a 38-year-old male with cardioembolic stroke.
• Clinical assessment of hemiplegia and cortical sensory loss (graphanesthesia, two-point discrimination, tactile inattention).
• Neuroimaging including CT scan and SPECT (Single-Photon Emission Computed Tomography) to assess cerebral infarction and regional cerebral blood flow (rCBF).
• Electrophysiological assessment using cortical somatosensory evoked potentials (SEPs).

Main Results:

• The patient presented with acute left hemiplegia and cortical sensory loss due to a haemorrhagic infarction in the right corona radiata and anterior limb of the internal capsule.
• On day 13, cortical SEPs were absent, and SPECT revealed bifrontal and left parietal hypoperfusion.
• By day 28, both sensory loss and SEPs improved, correlating with improved rCBF, suggesting a resolution of cerebral diaschisis.

Conclusions:

• Cortical sensory loss can occur secondary to subcortical lesions, potentially mediated by cerebral diaschisis.
• Improvements in regional cerebral blood flow are associated with the recovery of both sensory function and neurophysiological measures like SEPs.
• This case highlights the complex pathophysiology of sensory deficits following stroke and the utility of multimodal assessment.