INTRODUCTION
- Clinical assessment of a peripheral nerve lesion requires 1) the knowledge of the unique sensory territory and motor functions of the particular nerve, 2) the availability of a few examination tools, such as a tuning fork, a Disk-Criminator or paper clip and 3) calm environment.
- We will be dividing the assessment into performance components & performance areas for each nerve.
PERFORMANCE COMPONENTS
Sensori-motor
- Sensory assessment
- For sensory assessment, it’s good to keep in mind the order of recovery of sensation after PNI. The recovery is in the following order: pain & temperature, 30 cps vibration, moving touch, constant touch, 256 cps vibration.
- We have talked about light touch & pin prick assessment in our dermatome & myotome blog, we will be talking about other sensory assessments here in brief.
Temperature- test tubes of hot(40–45 degree celsius or 115- 120 fahrenheit, Trombly CA)) & cold(5–10 degree celsius, 40 degree fahrenheit) are used. Test tubes are placed over the skin areas & patient is asked to indicate ‘cold’ & ‘hot’.
Examination should be proximal-distal & to be performed on the non- affected limb first.
2 point discrimination- it is a good test for receptor density, use a device such as Disk-criminator, test only the fingertips as they have the highest receptor density & are used for exploration of objects, begin with a distance of 5 mm( for static 2 point) & 8 mm(moving 2 point). place or move the ends of disk-criminator on radial and ulnar aspects of the fingertips. Client will respond whether he felt just one point or 2 points or nothing at all.
Norms for interpreting results are as follows:
- 1–5mm — normal static 2 point discrimination
- 6–10mm — fair static 2 point discrimination
- 11- 15mm- poor static 2 point discimination
- one point indicates protective sensation
For moving 2 point- 2–4mm for ages 4- 60 & 4–6 mm for ages 60 & older is normal.
proprioception & kinesthesia- hold the lateral aspect of digits(IP joint), move the part into flexion/extension, for proprioception- client will mimic the movement on the other limb. For kinesthesia, client is asked to indicate the direction of movement as up/down. Avoid excess tactile stimulation.
vibration- use a tuning fork of 30,128 or 256 cps, hit the arms of tuning fork against your own hypothenar eminence or a pad and place the bottom of the fork on a bony point(styloid process, medial malleolus, cmc joint,etc). patient should be able to distinguish between vibrating & non-vibrating tuning fork.
tactile localization- ability to localize touch sensation on the skin, considered to be a test of functional sensation, can be done with constant or moving touch. Apply the finest semmes- weinstein monofilament that the client can perceive on th skin. when the client feels the touch, have him or her open his eyes and point to the spot where stimulus was felt. Correct identification of the area within 1 cm of actual placement indicates intact touch localization.
stereognosis- take familiar objects, or some nuts and bolts and ask the patient to identify the object without looking. Inability to identify an object through touching is called astereognosis.
*IMPORTANT- Check the autonomous zones of the nerves.These are the regions where single nerve roots supply distinct and non-overlapping areas of skin. Anesthesia in an autonomous zone indicates a complete lesion of that particular nerve.*
- MOTOR
- observe for atrophy.
- check muscle strength through MMT grading.
Special tests used in PNI
- EGAWA’S TEST- to test dorsal interossei(ulnar nerve).With hand kept flat on the table, patient is asked to move his middle finger sideways. For palmar interossei, the examiner inserts a card between 2 extended fingers & the patient is asked to hold it tightly as the examiner tries to pull the card out, known as CARD TEST.
- PEN TEST- to test abductor pollicis brevis(median nerve), a pen is kept at a level higher than the thumb & asked to touch the tip of the pen.
- FROMENT’S SIGN- compensatory thumb IP flexion by FPL during key pinch instead of adductor pollicis. Occurs due to ulnar nerve lesion.
TINEL’S SIGN- it is elicited by lightly percussing along the course of the affected nerve from distal to proximal. When the finger percusses over the zone of regenerating fibers, the patient will announce the sensation of pins and needles, which may be quite painful, into the cutaneous distribution of the nerve.
Reflexes- superficial(polysynaptic) reflexes- in a peripheral nerve disorder, superficial reflexes are normal.
deep tendon(monosynaptic) reflexes- in a peripheral nerve disorder, DTR is decreased or absent.
DTR’s are graded as : 0- no response, 1+present but depressed, 2+ average or normal, 3+increased or brisker than average,4+ hyperactive with clonus.
Muscle tone- decreased, as it is a lower motor neuron condition.
In lower limb, gait is also affected & if proprioception is affected, the person might be walking with a high- steppage gait, commonly seen in sensory ataxia.
psychosocial/psychological component
- Several research studies exist that have proven the detrimental effect of peripheral nerve injury on quality of life, anxiety, depression & social participation.
- PNI hinders with not only quality of life but also affects role performance, social conduct, self concept & self expression of a person.
- Some common scales/checklists that can be used for assessment are: COTE, COPM, Occupational therapy psychosocial assessment of learning, role checklist, MOHOST, etc.
PERFORMANCE AREAS
Since motor & sensory functions are affected of the hands & feet, ADL’S are commonly affected. we will be talking about the ADL’s in an order based on normal development in children:-
- Feeding- when hands are affected, ability to hold a spoon or breaking a chapati into pieces, holding a glass of water and the ability to cook food for self and others is also affected. Depending upon the severity, the level of assistance can vary.
- Continence- This activity might not be directly affected by PNI, but a person should be thoroughly assessed.
- Toileting- patient may face difficulty in arranging clothes & using self cleaning appliances.
- Undressing/dressing- client won’t be able to arrange, don/doff & button/unbuttoning due to involvement of hands.
- Bathing- client won’t be able to use soap, pour water, use shower appliances.
other ADL’s affected(not in order)
- Writing- client won’t be able to write in case dominant hand is involved.
- Using the phone/laptop
- Meal preparation
- Home management
Considering the holistic approach an OT takes, there are many aspects to OT assessment.
Thank you for reading!
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REFERENCES
- Pedretti’s occupational therapy: practice skills for physical dysfunction 7th edition
- Neurological examination- Geraint Fuller
- DeJong’s neurological exam
