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Assessing Sensory Assessing Sensory NeuropathyNeuropathy

Sanjeev KelkarSanjeev Kelkar

Conjoint LecturerConjoint Lecturer

Faculty of healthFaculty of health

University of Newcastle University of Newcastle

AustraliaAustralia

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Motor Sensory Autonom

MyelinatedMyelinated Thinlymyelinated

Un-myelinated

Thinlymyelinated

Un-myelinated

A A/ A C A C

LARGE SMALLMusclecontrol

Touch,vibration, position

perception

Coldperception,

pain

Warmperception,

pain

Heart rate, bloodpressure, sweating,

GIT function

A simplified view of the peripheral nervous system. GIT, gastrointestinal tract.

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Clinical presentation of large-Clinical presentation of large-

fibre neuropathiesfibre neuropathies

• Impaired vibration perception (often the Impaired vibration perception (often the

first objective evidence) and position first objective evidence) and position

sense.sense.

• Depressed tendon reflexes.Depressed tendon reflexes.

• AA type deep-seated gnawing, dull, like a type deep-seated gnawing, dull, like a

toothache in the bones of the feet or even toothache in the bones of the feet or even

crushing or cramp-like pain.crushing or cramp-like pain.

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Clinical presentation of large-fibre Clinical presentation of large-fibre

neuropathiesneuropathies

• Sensory ataxia (waddling like a duck)Sensory ataxia (waddling like a duck)

• Wasting of small muscles of feet with Wasting of small muscles of feet with

hammertoes (intrinsic minus feet and hammertoes (intrinsic minus feet and

hands) with weakness of hands and feet.hands) with weakness of hands and feet.

• Shortening of the achilles tendon with pes Shortening of the achilles tendon with pes

equinus.equinus.

• Increased blood flow (hot foot).Increased blood flow (hot foot).

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Need to Detect, Quantify and PreventNeed to Detect, Quantify and Prevent

Neuropathy In Diabetes. Neuropathy In Diabetes.

Foot UlcerationFoot Ulceration

GangreneGangrene

AmputationAmputation

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Androclese and the lionAndroclese and the lion• After identifying After identifying

lions foot/paw lions foot/paw problem, problem, Androcleas Androcleas removed the removed the thorn in his paw. thorn in his paw. Treated his ulcers Treated his ulcers and may be they and may be they lived happily ever lived happily ever after…….!!!!after…….!!!!

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Pay backPay back

All patients of diabetes of All patients of diabetes of some duration need testing. some duration need testing.

Every third person is likely to Every third person is likely to be a neuropathic.be a neuropathic.

We must know his relative risk We must know his relative risk to prevent ulceration to prevent ulceration

A worthwhile investment, likely A worthwhile investment, likely to pay back more than usual to pay back more than usual ..

Androcleas says every third Androcleas says every third lion diabetic has the painless lion diabetic has the painless thorn of neuropathy. He thorn of neuropathy. He needs quantification.needs quantification.

The third Lion

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Factors and markers of low-risk versus Factors and markers of low-risk versus high-risk diabetic feethigh-risk diabetic feet

Low-risk foot High-risk footLow-risk foot High-risk foot

All of the following:All of the following: One or more of the One or more of the

following:following: following:following:

Intact protective sensation Loss of protective Intact protective sensation Loss of protective

sensationsensation

Pedal pulses present Absent pedal pulsesPedal pulses present Absent pedal pulses

No severe deformity Significant foot No severe deformity Significant foot

deformitydeformity

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Factors and markers of low-risk versus Factors and markers of low-risk versus high-risk diabetic feethigh-risk diabetic feet

Low-risk foot High-risk footLow-risk foot High-risk footAll of the following:All of the following: One or more of theOne or more of thefollowing:following: following:following:

No prior foot ulcer History of foot ulcer No prior foot ulcer History of foot ulcer or callus pre-ulcerative callus or callus pre-ulcerative callus

No amputation Prior amputationNo amputation Prior amputation Normal joint mobility. Limited joint mobilityNormal joint mobility. Limited joint mobility

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What do we have to assess Neuropathy?What do we have to assess Neuropathy?

Need to assess associated risk

of ulceration in a neuropathic

Need to distinguishNeuropathic and non neuropathic patients

Need to establishwide range of quantitated

gradation of sensory deficitsfor comparison on

Follow up

Needsimple testing

equipment

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Tuning fork - 1Tuning fork - 1

• The sensory exam should be done in a quiet The sensory exam should be done in a quiet and relaxed setting. First apply the tuning and relaxed setting. First apply the tuning fork on the patient’s wrists (of elbow, or fork on the patient’s wrists (of elbow, or clavicula) so that patient knows what to clavicula) so that patient knows what to expect.expect.

• The patient must not be able to see if and The patient must not be able to see if and where the examiner applies the tuning fork. where the examiner applies the tuning fork. The tuning fork is applied on a bony part on The tuning fork is applied on a bony part on the dorsal side of the distal phalanx of the the dorsal side of the distal phalanx of the first toe.first toe.

• It should be applied perpendicularly with a It should be applied perpendicularly with a constant pressure.constant pressure.

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Tuning fork - 2Tuning fork - 2

• Repeat this applications twice, but alternate Repeat this applications twice, but alternate this with at least one “sham” application, in this with at least one “sham” application, in which the tuning fork is not vibrating.which the tuning fork is not vibrating.

• The test is positive if the patient correctly The test is positive if the patient correctly answered at least two out of three answered at least two out of three applications, and negative (at risk for applications, and negative (at risk for ulceration) with two out of three incorrect ulceration) with two out of three incorrect answers.answers.

• If the patient is unable to sense the If the patient is unable to sense the vibrations at the big toe, the test is repeated vibrations at the big toe, the test is repeated more proximally (malleolus, tibial more proximally (malleolus, tibial tuberositas).tuberositas).

• Encourage the patient during testing.Encourage the patient during testing.

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Vibration perception assessed with 128 Hz tuning fork

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The Rydel Seiffer tuning fork : An inexpensive device for screening

diabetic patients with high risk foot.

Vijay Viswanathan et al. Pract. Diab. Int.(In print).

It is a 128HZ graduated tuning fork

which allows quantifiable assessment of

vibration perception in the feet of

diabetic patients.

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Differing methods to measure VPT

Method Technique Usefulness

128-Hz tuning fork Sensation normal(cf.hand/ Only to detect

presence

forehead,reduce or absent or absence of neuropathy

Reidell-Seiffer

graduated tuning fork Ascending method Coefficient of variation compares

(Firma Martin, favorably with more complex

Tuttlingen, Germany) techniques below

Biothesiometer

(Biomedical Instrument Ascending method Largely superseded by

Newbury, OH) Neurothesiometer

Neurothesiometer

(Arnold Howrwell, Ascending method Currently most widely used.

London) Interobserver and intersubje coefficient of variation ~ 10%.

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Pressure perception assessed with 5.07/10g Semmes-Weinstein monofilament.

Plantar aspect of first and fifth metatarso-phalageal joints gives best sensitivity (80%) and specificity (86%)

(McGill.M et al, 1999 – Diabetes Care)

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• In an recent study in an outpatient clinic, In an recent study in an outpatient clinic, which examined the reproducibility of which examined the reproducibility of screening using a monofilament, screening using a monofilament, biothesiometer and palpation of pedal biothesiometer and palpation of pedal pulses, only the monofilament gave pulses, only the monofilament gave adequately reproducible results (over 85%) adequately reproducible results (over 85%) for measurements repeated after 2 weeks.for measurements repeated after 2 weeks.

[Klenerman L, et al. Diabet Med 1996].[Klenerman L, et al. Diabet Med 1996].

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Detection of neuropathyDetection of neuropathy

• Identification of neuropathy based on Identification of neuropathy based on

insensitivity to a 10 gm (5.07) nylon insensitivity to a 10 gm (5.07) nylon

monofilament is convenient and appears to monofilament is convenient and appears to

be cost-effective.be cost-effective.

[Gadsby R, McInnes A. Diabet Med 1998][Gadsby R, McInnes A. Diabet Med 1998]

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Semmes-Weinstein monofilament - 1Semmes-Weinstein monofilament - 1

• Sensory examination should be done in a Sensory examination should be done in a quiet and relaxed setting. First apply the quiet and relaxed setting. First apply the monofilament on the patient’s hands (or monofilament on the patient’s hands (or elbow, or forehead) so the patients know elbow, or forehead) so the patients know what to expect.what to expect.

• The patient must not be able to see if and The patient must not be able to see if and where the examiner applies the filament. where the examiner applies the filament. The three sites to be tested on both feet The three sites to be tested on both feet are indicated.are indicated.

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Semmes-Weinstein monofilament - 2Semmes-Weinstein monofilament - 2

• Apply the monofilament perpendicular to Apply the monofilament perpendicular to the skin surface.the skin surface.

• Apply sufficient force to cause the Apply sufficient force to cause the filament to bend or buckle.filament to bend or buckle.

• The total duration of the approach, skin The total duration of the approach, skin contact, and removal or the filament contact, and removal or the filament should be approximately 2 seconds.should be approximately 2 seconds.

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Semmes-Weinstein monofilament - 3 Semmes-Weinstein monofilament - 3

• Apply the filament along the perimeter Apply the filament along the perimeter of and not on an ulcer site, callus, scar of and not on an ulcer site, callus, scar or necrotic tissue. Do not allow the or necrotic tissue. Do not allow the filament to slide across the skin or filament to slide across the skin or make repetitive contact at the test site.make repetitive contact at the test site.

• Press the filament to the skin and ask Press the filament to the skin and ask the patient IF they feel the pressure the patient IF they feel the pressure applied (yes/no) and next WHERE they applied (yes/no) and next WHERE they feel the pressure applied (left/right feel the pressure applied (left/right foot).foot).

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• Semmes-Weinstein monofilament –Semmes-Weinstein monofilament – 4 4

• Repeat this application twice at the same Repeat this application twice at the same site, but alternate this with at least one site, but alternate this with at least one “sham” application, in which no filament is “sham” application, in which no filament is applied (total three questions per site).applied (total three questions per site).

• Protective sensation is present at each site Protective sensation is present at each site if the patients correctly answers two out of if the patients correctly answers two out of three applications. Protective sensation is three applications. Protective sensation is absent with two out of three incorrect absent with two out of three incorrect answers, and the patient is then considered answers, and the patient is then considered to be at risk of ulceration.to be at risk of ulceration.

• Encourage the patients during testingEncourage the patients during testing. .

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MonofilamentsMonofilaments to detect the foot at risk, to detect the foot at risk, That too for multiple use. That too for multiple use.

Up to five patients can be tested with one Monofilament

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Semmes-Weinstein monofilament - 5Semmes-Weinstein monofilament - 5

Monofilament: When applied perpendicular to Monofilament: When applied perpendicular to thethe

foot it buckles at a force of 10 gms, tests foot it buckles at a force of 10 gms, tests touch &touch &

pressure pressure

Areas to be tested - metatarsal heads of first, Areas to be tested - metatarsal heads of first, third and fifth and the plantar surface of heel. third and fifth and the plantar surface of heel.

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Semmes-Weinstein monofilament Semmes-Weinstein monofilament - 5- 5

The validity of SW monofilament for The validity of SW monofilament for predicting the neuropathy by predicting the neuropathy by nerve conduction study criteria are nerve conduction study criteria are confirmed by Perkins BA, 2001,confirmed by Perkins BA, 2001,

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Semmes-Weinstein monofilament - 5Semmes-Weinstein monofilament - 5

SW Monofilament has a Sensitivity SW Monofilament has a Sensitivity 77%, specificity 98% with a + ve 77%, specificity 98% with a + ve and – ve likelihood ratios of 10.2 and – ve likelihood ratios of 10.2 and 3.4 respectively for 4 to8 and 3.4 respectively for 4 to8 imperceptible stimuli on great toe imperceptible stimuli on great toe bilaterally. (Perkins, BA 2001)bilaterally. (Perkins, BA 2001)

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Semmes-Weinstein monofilament - 6Semmes-Weinstein monofilament - 6

Monofilaments help classify foot at risk forMonofilaments help classify foot at risk for

touch pressure. (5.07/10gms)touch pressure. (5.07/10gms)

Diagnosed clinically by reduced sensitivity Diagnosed clinically by reduced sensitivity

to 10 g Semmes Weinstein monofilament. andto 10 g Semmes Weinstein monofilament. and

pricking sensation using the Waardenbergpricking sensation using the Waardenberg

wheel or similar instrument testing sensation wheel or similar instrument testing sensation toto

light touch and pinprick - Sensitivity 71%light touch and pinprick - Sensitivity 71%

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Semmes-Weinstein monofilament - 7Semmes-Weinstein monofilament - 7

Filament not to be applied over the callusFilament not to be applied over the callus

The advantage of the assessment with The advantage of the assessment with monofilaments is a foot at risk can be monofilaments is a foot at risk can be decided in 2 seconds and segregated for decided in 2 seconds and segregated for detailed analysisdetailed analysis

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Semi-Quantitative test Semi-Quantitative test for for neuropathic assessment neuropathic assessment

Pricking sensation can be tested by Pricking sensation can be tested by using the Waardenberg wheel or using the Waardenberg wheel or similar instrument similar instrument testing testing sensation tosensation to

light touch and pinprick -light touch and pinprick -