Dissociated Sensory Loss

It is a useful generalization to state that pain/temperature sensation and touch/vibration/joint position sensation follow two distinct pathways.
1. Pain/temp in spinothalamic pathway
2. Touch/vibration/jt position in dorsal column

Damage to either pathway in isolation results in dissociated sensory loss. The damage usually occurs in the spinal cord.

1. Causes of spinotahlamic loss

• Syringomyelia
• Brown-Sequard syndrome - contralateral leg
• Lateral medullary syndrome - contralateral to other signs
• Anterior spinal artery thrombosis

2. Causes of doral column loss

• Subacute degeneration of the spinal cord
• Multiple sclerosis
• Brown-Sequard syndrome - the ipsilateral leg
• Tabes dorsalis
• Spinocerebellar degeneration e.g. Friedreich's ataxia