Contra-lesional somatosensory cortex activity and somatosensory recovery in two stroke patients

We describe here 2 stroke patients who showed activation of the contra-lesional somatosensory cortex without activation of the ipsi-lesional somatosensory cortex during proprioceptive input on the affected hand.

One patient with intracerebral haemorrhage (a 52-year-old man), 1 patient with middle cerebral artery infarct (a 54-year-old man), and 8 control subjects were recruited. The subscale for kinaesthetic sensation (full mark: 24) of the Nottingham Sensory Assessment improved from 2 points (patient 1 and 2; onset) to 8 points (patient 1) and 12 points (patient 2) at 6 months after onset. Functional magnetic resonance imaging was conducted at 6 months after onset using a 1.5-T Philips MR scanner. Passive movements were performed at the metacarpophalangeal joint.

On functional magnetic resonance imaging the contra--lesional (left) primary somatosensory cortex and posterior parietal cortex were activated during passive movements of either hand, which was not observed in control subjects.

The activation of only the contra-lesional somatosensory cortex during passive hand movements in these patients suggests the involvement of this area in somatosensory processing for passive movements after stroke. This area appeared to contribute to recovery of proprioceptive function of the affected hands after stroke.