Useful Selected Questions to Ask/Facts to Establish?

• Establish the character of the sensory disturbance (e.g. an absence of sensation (numbness), an uncomfortable sensation (dysaesthesia) or a burning or painful sensation).
  
• Location: Distribution of sensory symptoms and signs is important for anatomical localisation of the problem, i.e. brain, cord, root or roots, plexus, peripheral nerve or nerves. For example

Are the symptoms and signs in a specific dermatomal pattern implying a radiculopathy (nerve root entrapment) or in an area innervated by a single nerve (little and lateral half of ring finger in ulnar nerve entrapment)?

Is the problem more widespread and if so is this likely to be central or peripheral?

If central, is the problem in the brain where a contralateral hemisensory disturbance may be seen or in the cord where a bilateral sensory loss below the level of the lesion may occur?

If peripheral, are multiple nerves involved (polyneuropathy), and if so, are they large fibres (vibration and proprioceptive loss with loss of reflexes) or small fibres (burning pain) that are predominantly affected?

• Mode of onset and duration: Establish whether sudden versus gradual and transient versus permanent? This helps in distinguishing between the different causes (e.g. transient disturbances in a migrainous episode, a focal seizure or a transient ischaemic attack; permanent sensory disturbance may imply a structural pathological lesion at different levels of the CNS and PNS, including a neoplasm or haematoma (subdural or intraparenchymal) or an infarct in the brain, spondylotic changes compressing the spinal cord and radiculopathy related to disc herniation in lumbar or cervical spine; demyelination, for example related to multiple sclerosis, may cause transient or permanent sensory disturbances).
  
• Associated disturbances (e.g. associated motor signs or sphincter (bowel and bladder) disturbances, specifically the presence of bowel and bladder dysfunction (e.g. urinary retention) in association with saddle anaesthesia (in the region of anus, perineum, genitals, and buttocks) and sciatica may raise the suspicion of cauda equina syndrome related to a herniated lumbar disc).