3) Performing a Lower Extremity Neurological Exam

Question 1

Neuropathic ulcers and neuropathic joints develop because of

Answer 1

• Lack of pain perception

- Pain is a protective mechanism

Question 2

When inspecting the motor system, the following points should be assessed

Answer 2

• Resting posture (unusual rotation or posture of a joint)
• Is the patient symmetrical
• Muscle wasting or hypertrophy (focal or diffuse)
• Involuntary movements (tremor, tics, myoclonic jerks, chorea or athetosis)
• Muscle fasciculation (LMN disease)
• Subcutaneous twitches over a muscle belly at rest (tapping the belly may stimulate fasciculation)

Question 3

Sharp touch

Answer 3

• Disposable pin
• Sternal area to establish a baseline
• Follow the same progression as with light touch, comparing both lower limbs
• Ask the patient to report hypoaesthesia (feels blunter) or hyperesthesia (feels sharper)

Question 4

Temperature

Answer 4

• Compare the quality of temperature sensation on arms, face, trunk, hands, legs and feet
• Containers of warm and cool water may be used for more accurate assessment
• Ask the patient to distinguish between warm and cool on different areas of the skin with their eyes closed

Question 5

Proprioception

Answer 5

• Test at IPJ of the big toe
• Hold the proximal phalanx with one thumb and finger and hold the medial and lateral sides of the distal phalanx with the other
• Move the distal phalanx up and down
• Ask the patient to tell you the direction of movement each time
• Test on both feet
• If there is an abnormality, move backwards to the MPJ and so on until joint position sense is normal

Question 6

Vibration sense

Answer 6

• 128 Hz tuning fork
• Place it on the sternum to start with so that the patient can feel the sensation
• Then place it on the big toe
• No vibration? move backwards to the bony malleolus of the ankle, the tibial shaft and tuberosity and the anterior iliac crest

Question 7

2-point discrimination

Answer 7

• Calipers or areshaped paperclip
• Alternate randomly between touching the patient with one point or with two points on the area being tested (finger, arm, leg, toe)
• The patient is asked to report whether one or two points was felt
• NOT usually performed on the soles of the feet because the distinguishing distance is usually much greater than that on the fingers

Question 8

If there is a spinal cord lesion, there may not be equal diminution across all the sensory modalities

Answer 8

• Light touch, vibration and joint position sense may remain intact while sharp touch and temperature are lost
• This is because the lateral spinothalamic pathways may be damaged while the dorsal columns remain intact

Question 9

Tone

Answer 9

• The resistance felt when a joint is moved passively through its normal range of movement

Question 10

Hypertonia vs. hypotonia

Answer 10

• Hypertonia is found in upper motor neuron lesions

- Hypotonia is found in lower motor neuron lesions and cerebellar disorders

Question 11

Clonus

Answer 11

• Rhythmic and involuntary muscle contraction that can be provoked by stretching a group of muscles

Question 12

Testing tone

Answer 12

• Ask the patient to let their legs ‘go floppy’
• Internally and externally rotate the ‘floppy’ leg
• Assess for any increased or reduced tone
• Then lift the knee off the bed with one of your hands
• Note whether the ankle raises off the bed as well, signifying increased tone

Question 13

Testing for ankle clonus

Answer 13

• Flex the patient’s knee, resting the ankle on the bed
• Dorsiflex the foot quickly and keep the pressure applied
• You will be able to see the foot moving up and down if clonus is present

Question 14

When assessing power, you must test the following

Answer 14

• Hip flexion, extension, adduction and abduction
• Knee flexion and extension
• Foot dorsiflexion, plantar flexion, eversion and inversion
• Toe plantar flexion and dorsiflexion

Question 15

Deep tendon reflexes can be

Answer 15

• Hyperactive (+++)
• Normal (++)
• Sluggish (+)
• Absent (-)
• (±) is used when the reflex is only present on reinforcement

Question 16

Muscle stretch reflexes (deep tendon reflexes) grade scale

Answer 16

• 0 = absent
• 1 = present with reinforcement
• 2 = normal
• 3 = enhanced
• 4 = unsustained clonus
• 5 = sustained clonus

Question 17

Interpretation of DTR

Answer 17

• Upper motor neuron lesions usually produce hyperreflexia

- Lower motor neuron lesions usually produce a diminished or absent response

Question 18

Superficial tendon reflexes

Answer 18

• An extensor plantar response (upgoing big toe) is pathological (+ Babinski’s sign) and signifies an upper motor neuron lesion

Question 19

Babinski’s sign

Answer 19

• Dorsiflexion of the big toe and abduction of the other toes
• Physiologically, it is normally present in infants from birth to 12 months
• After 12 months = non-specific upper motor neuron lesion

Question 20

Heel-shin test (cerebellar/coordination exam)

Answer 20

• Ask the patient to lift one of their legs and flex it at the knee, keeping the other leg straight
• They should then place the heel of the flexed leg on the knee of the other leg and run it down the shin towards the ankle and back again towards the knee
• Ask them to repeat this several times

Question 21

Heel-toe test (coordination)

Answer 21

• This tests balance mechanisms that rely on the cerebellar, vestibular and proprioceptive systems
• The patient either needs to be barefoot or wearing flat shoes
• Walk in a straight line so that the heel of the second foot touches the toes of the first foot, repeat
• Look at how well they are able to perform this
• Is there any staggering which would suggest a lesion of the cerebellum

Question 22

Romberg’s test (coordination)

Answer 22

• This also tests balance mechanisms that rely on the cerebellar, vestibular and proprioceptive systems
• Ask the patient to keep their eyes open and stand with their feet together, arms by their sides
• Then ask them to maintain this position when they close their eyes
• Patients who have cerebellar lesions often cannot stand in this position, even with their eyes open
• If balance is only lost when the eyes are closed, this signifies a proprioceptive or vestibular lesion
• Be ready to catch the patient by standing behind

Question 23

Examination of gait

Answer 23

• Assess cerebellar function
• Romberg’s test
• Finger-nose pointing
• Dysdiadochokinesia
• Heel-to-shin testing

Question 24

Significant observations during gait exam

Answer 24

• Shuffling gait
• Balance
• Postural sway
• Rate of walking
• Steppage gait
• Difficulty turning
• Widened base
• Difficulty rising from chair

Question 25

Shuffling gait

Answer 25

- May suggest Parkinsonism | - This is also associated with a flat foot strike in heel-to-toe testing with a reduced loading at the heel

Question 26

Balance

Answer 26

- Do they veer off course? | - This suggests cerebellar dysfunction

Question 27

Postural sway

Answer 27

- Feature of late-stage Parkinson's disease and other conditions of poor balance - Balance cannot be maintained through standing, turning or walking - In Parkinson's disease it relates to lack of flexibility in shifting postural responses

Question 28

Rate of walking

Answer 28

- Do they start off slowly and then speed up (a Parkinsonian characteristic) - Is there general slowness (eg, joint degenerative disease, weakness)

Question 29

Steppage gait

Answer 29

- Due to foot drop (loss of dorsiflexion) | - Needs to lift leg higher than normal

Question 30

Steppage gait is associate with conditions such as

Answer 30

- Peroneal nerve injury - Fibular injury - Multiple sclerosis - Guillain-Barré syndrome - Prolapsed intervertebral disc

Question 31

Difficulty turning

Answer 31

- Common with any gait disorder; turning is generally more difficult than walking - No balance or gait problems? about-face in one or two steps - Nonspecific problems? three or four steps - Five or more steps likely to have cerebral or basal ganglia dysfunction

Question 32

If a patient has less trouble turning than walking forwards

Answer 32

- A psychogenic disturbance is likely

Question 33

Widened base

Answer 33

- With frank ataxia, base width is about 12 inches - If base width approaches two feet, the likelihood of psychogenic gait disorder rises (unless the patient has morbid obesity or an obvious structural explanation)

Question 34

The assessment and examination of gait and balance need to be supplemented by

Answer 34

- Appropriate history and examination of all systems | - Attention must be paid to speed of onset and rate of any deterioration

Question 35

Acute deterioration in gait

Answer 35

- Feature of many serious conditions requiring urgent assessment and intervention - Vascular, infective, neoplastic, neurological, metabolic and toxicological conditions and acute confusional states