1. needed for early learning
2. affects motor performance
3. is essential for effective movement
4. reception, transmission, interpretation
5. sensory stimuli conveyed to the central interpretive centers by afferent nerves
6. ANY loss of sensation in the HAND
7. impairs tactile feedback
1. slows the patient
2. increases risk of injury
3. vision needed to compensate

1. Assess the extent of sensory loss
2. Evaluate & document sensory recovery
3. Assist in diagnosis
4. Provide prognostic information
5. Determine impairment & functional limitation
6. Provide direction to OT treatment

1. sensory retraining
2. compensatory techniques
3. splints

**Tests of sensory function DO NOT always accurately predict functional use of the hand.

Special Sensory Systems Somatosensory

-auditory -touch
-gustatory -movement
-olfactory -temperature
-vestibular -pain
-visual

As OT's:

Evaluate FUNCTION
        -fn. hand tests
        -simulated activities
        -ADL performance

Who can benefit from sensory testing?

1. CNS dysfunction
2. PNS dysfunction

Recovery depends on:
etiology

1. severity
2. location of the lesion
3. learning to use alternative strategies
4. motivation
5. cognitive level

Patients with:

1. CNS dysfunction- loss of sensation over generalized areas
2. PNS dysfn. - loss of sensation over specific areas

-burns: skin sensory receptors are destroyed
-arthritis: possible nerve compression
-traumatic hand injuries

Somatosensory Physiology:

1. Primary or Protective System

1. receives & interprets simple sensations
2. awareness of touch
3. awareness of pain & temperature
4. uses spinothalamic route

1. Discriminative System

1. + complex, integrated experiences (location of touch; 2pt discrimination; stereognosis)
2. Fn: Perceptual

General Principles for testing:

1. Pt. needs to be comfortable & relaxed
2. Comfortable room temperature
3. Decrease distractions
4. Understanding of language
5. Hand or instrument applying stimulus needs to be stabilized
6. Note any differences in skin thickness, callouses. Expect decreased sensation in these areas.

1. Present test stimulus randomly
2. Multiple trials for each modality & each area to be tested
3. Establish time limit for the response to occur.
4. Learning trials precede
5. Test contralateral UNINVOLVED areas before affected ones
6. Apply stimuli proximally to distally (CONTROVERSIAL)
7. Vision occluded
8. Uniform scoring
9. Note accuracy & speed
10. Avoid fatigue

Type of Test What it measures

1. superficial pain - detects painful stim.

(sharp/dull) - (necessary to decrease risk of injury)

2. light touch - ability to recognize & localize light touch
                            localization of stimuli

- (necessary for knowing an object is in the hand)

**Contraindicated for receptive aphasic

3. pressure sensation - threshold of pressure sensation

• ( needed for ADL)

4. Temperature - hot/cold discrimination

• (necessary for prevention of injury)

5. olfactory - sense of smell

-(fumes, dec. taste)

6. gustatory - sense of taste

-(necessary for salivation & swallowing)

7. proprioception - position sense

-(necessary for posture)

8. stereognosis - tactile perception

-(identify objects without vision)

9. graphesthesia    - recognizes "writing" on skin

10. vibration - sense of vibration

11. 2-point - innervation density

-stationary
-moving

Semmes - Weinstein:

  4.31- Purple- Diminished protective sensation

• Pt. will have difficulty manipulating objects
• Pt. may complain of weakness in the hand
• appreciation of pain & temperature is present but may be decreased

Moving Two Point Discrimination:

TESTING:

1. The pt's vision is occluded
2. An area of normal sensation is tested as a reference, using calipers
3. The fingertip is supported by the examining table or the examiner's hand
4. The caliper, separated 5mm to 8mm, is moving longitudinally from proximal to distal in a linear fashion along the surface of the fingertip. One & two points are randomly alternated. The patient must correctly identify the stimulus 7 out of 8 responses before proceeding to a smaller value. The test is repeated down to a separation of 2mm.

• two point values increase with age in both sexes
• females tens to have smaller values than men
• there are no significant differences between dominant & non-dominant hands

Static Two Point Discrimination:

TESTING:

1. Pt's. vision is occluded
2. An area of normal sensation is tested as a reference, using calipers
3. Calipers are set 10 mm apart & randomly applied starting at fingertip & moving proximally & longitudinally in line with the digital nerves, with two points touching. The skin should not be blanched by the caliper.
4. The distance is decreased until the pt. no longer feels two distinct points, and that distance is measured.

SCORING:

*normal 2 point discrimination at fingertips is 6mm
*3 to 4 seconds should be allowed between applications and the pt. should have 4 out of 5 correct responses

Objective Tests:

1.) Ninhydrin Test -identifies dec. sweat secretion 
                              -sympathetic function

2.) O'Riain Wrinkle Test
                            -identifies areas of denervation

3.) Nerve Conduction Studies
                            -invasive

1. Tinel's Sign

   -tapping skin over damaged peripheral nerve

   -elicits tingling or "pins & needles"

2.) Phalen Test -wrist flexion

WHAT ARE EMG & NCS?

*they are special tests used to detect neuromuscular disorders

EMG (Electromyography)- can measure the electrical activity of muscles

NCS (Nerve Conduction Studies)- also called nerve conduction velocity tests

Can measure the speed & intensity of electrical signals that travel along nerves and the time it takes muscles to respond to these signals.

WHAT ARE THE MAJOR USES OF EMG & NCS?

They can help diagnose:

• pinched nerves & inflamed muscles, due to injury, a ruptured disc, disease or other conditions
• carpal tunnel syndrome- pressure to median nerve, causing pain in the wrist or hand
• primary muscle disorders, such as muscular dystrophy
• neuromuscular disorders, such as myasthenia gravis
• nerve disorders, such as amyotrophic lateral sclerosis

1. Desensitization

1. grade stimulus from soft to hard to rough
2. grade force of application from touch to:

1. Compensation- Ex: padding objects

 

Tx for Hyposensitivity (dec. sensation)

1. Sensory Retraining- learn the meaning of new sensation

1. vigorous, generalized cutaneous stimulation (Ex: rub affected area briskly with terrycloth)
2. cognitive cueing (Ex: OT & pt. discuss stimuli)
3. feedback (Ex: visual feedback)

1.Teach pt. precautionary techniques

2.Compensatory techniques

• visual
• auditory