Sensory Exam

Question 1

Sensory Intregration

Answer 1

• Sensory integration is the ability of the brain to organize, interpret, and use sensory info
• somatosensation (somatosensory) refers to sensation received from the skin and musculoskeletal system (as opposed to that from specialized senses such as sight or hearing)
• examination of sensory function involves testing patient’s ability to interpret and discriminate among sensory info

Question 2

The sensory system

Answer 2

sensory info, detected at peripheral receptors, travels via peripheral nerves, nerve roots, spinal cord, brainstem and thalamus to the sensory cortex

pain and temp sensation
-carried by small unmyelinated fibers
-carried in the spinothalamic tract
-decussates (crosses over) immediately in the spinal cord
-exteroreceptors

Vibration and proprioception (joint position)
-carried by large myelinated fibers
-carried on dorsal columns
-ascend on the same side of SC
-cross over in brain stem
-proprioceptors in joints, muscles, ligaments, ect

Combined cortical sensations
-steregnosis, barognosis, 2 point descimination
-recognition of texture

Question 3

Normal sensory examination

Answer 3

Normal sensation allows a patient to detect
* pain (pin prick) and temp in whichever area is tested
* vibration at tips of fingers and toes
* joint postion (i.e. small amplitude movements) at distal joints

Localization of problems can be determined by knowlege of area skin supplied by peripheral nerves, sensory dematomes, decussation of spinothalamic tract and dorsal columns

Question 4

Examination

Answer 4

• allow the pt. to describe the change in sensation
  -what it feels like (pins & needles, numbness, etc)
  -location of symptoms
• based on subjective report-determine tests needed and proceed
• test area reported to be abnormal as well as normal
• map area affected
• decide if it makes anatomical sense

Question 5

Patterns of sensory loss

Answer 5

• The pattern of sensory loss or abnormality helps to localize the lesion to specific parts of the NS
• The initial distinction is whether the lesion is in the central or peripheral NS
• A good way of achieving this to recognize patterns of sensory loss caused by
  -sc lesions
  -nerve root lesions
  -peripheral neuropathy
  -peripheral nerve lesion

Question 6

Spinal cord lesion pattern

Answer 6

• sensation is lost or altered below the level of the lesion
• the extent of the lesion determines whether the loss of sensation uni- or bilateral
• familiarity with cross sections of cord and sites of where the main tracts decussate will enable you to understand in details of the pattern of sensory loss

Question 7

Peripheral Neuropathy

Answer 7

• loss, altered or abnormal sensation starts at the periphery (distal ends of longest nerves) and spreads proximally
• toes and feet will ne affected before fingers and hands
• this produces a “glove and stocking” pattern of sensory loss
• the types of nerve fibers affected (myelinated, unmyelinated, or both) determine which sensations are involved
• common with diabetic pts.

Question 8

Sporadic sensory loss

Answer 8

systemic pathology can produce unpredictable or scattered patterns of sensory loss
ex. Multiple sclerosis & guillon barre