fj me Malik revised

7/23/2019 fj me Malik revised

1/5

ARTICLE

The Neuropathic Pain Scale and its reliabilityand validity for diabetic neuropathy

Tauqeer Ahmed Malik, Hussam Eddine Saleh Itani, Nashat Ali Gandoura

Pain is a subjective experience and as such is difficult to assess objectively. The

common method of assessment is to use a pain scale so that patients can rate

different aspects of their experience of pain. Neuropathic pain, which is caused

by a dysfunction of the nervous system and is often associated with the diabetic

foot, can be assessed using the Neuropathic Pain Scale. This article reviews theliterature for the Neuropathic Pain Scale to assess its reliability and validity in

identifying levels of neuropathic pain. The authors conclude that the NPS is a

valid and reliable tool.

Pain is a sensation that the majority of us

will have experienced in varying degrees

throughout our lives. Various definitions of

pain have been used over the years. In 1986, the

International Association for the Study of Pain

(IASP)[1]described it as:

an unpleasant sensory or emotional experience

associated with actual or perceived tissue damage

or expressed in terms of such damage.

In Bonicas Management of Pain[2], it is argued

that the IASP should have included definitions of

acute, chronic, recurrent and cancer pain. In 2008,

the World Union of Wound Healing Societies

(WUWHS)[3]defined wound pain as:

a noxious symptom or unpleasant experience

directly related to an open skin ulcer.

Wound pain may arise from various wound

aetiologies, such as the diabetic foot, pressure ulcers

and arterial and venous leg ulcers[46]. Acute pain

is temporally related to injury. It is felt instantly,

it is localised, and it is often described as a sharp,

pinprick type of pain which eventually subsides

as the wound heals[7,8]. In contrast, chronic pain

is background pain that is persistent at rest and

between wound-related procedures, and extends

for more than three months or lasting longer than

a wound that is healing on a normal trajectory[7,9].

Pain is multidimensional, experienced by

an individual and not only involves physical

sensation, but also has a psychological impact[10,11].

Mood, personality, coping style, the degree of

preparation, uncertainty, control over the pain,

past experience of pain, and social and religious

influences are various psychological and social

factors that can affect an individuals ability to

cope with pain[10,12,13]. Carr[14] highlighted the

presence of bias among healthcare professionals

in their assessment of pain based on their

expectations of how certain individuals should

cope with pain. He concluded that the experience

of pain is influenced by age, past experience of

pain, gender, and culture, therefore, all need to

be considered while planning for appropriate

and effective care. However, pain and suffering

are private, internal events that cannot be

directly and empirically observed by clinicians,or assessed via blood tests or X-rays [11], and as

expressed by McCaffery[12]:

pain is what the experiencing individual tells

you it is and exists when he/she says it does.

In order to understand pain, communication

between the patient and the clinician is mandatory.

This may help to achieve a correct diagnosis and

determine the intensity, quality and duration

of pain, as well as evaluating the effectiveness

of pain therapy[16]. Therefore, the assessment of

pain requires a psychosocial, behavioural and

organic approach, which encompasses not only

the severity of pain and related pathology, but

AuthorDr Tauqeer Ahmed Malik isa Senior Registrar G Surgery,Diabetic Foot Surgeon and WoundCare at the King Fahad ArmedForces Hospital Jeddah, KSA; DrNashat Ali Gandoura is ConsultantGeneral and Diabetic Foot Surgeonat, King Fahad Hospital in Jeddah,KSA; Dr Hussam Eddine SalehItani, Wound Care Consultant andEducator, Dubai, UAE

12 The Diabetic Foot Journal Middle East Vol 1 No 1 2015


2/5

THENEUROPATHICPAINSCALEANDITSRELIABILITYANDVALIDITYFORDIABETICNEUROPATHY

also of the individual[17]. Failure to assess wound

pain may lead to significant distress for the

patient[18].Pain assessment tools are generally simple to

use, efficient and minimally intrusive and are

used primarily for acute pain management in

hospital settings. They include: verbal rating

scales (VRS), numerical rating scales (NRS), and

visual analogue scales (VAS)[16]. The NRS asks the

patient to rate their pain from 0 to 10 (11 point-

scale) or from 0 to 100 (101-point scale), with 0

equal to no pain and 10 or 100 equal to the worst

possible pain. NRSs are valid, reliable, easy to

administer and score, and include the Brief PainInventory (BPI)[19], LANNS Pain Scale[20]and the

Neuropathic Pain Scale (NPS)[21,22]. This article

will consider the NPS in detail using a literature

review to identify studies that have evaluated its

effectiveness.

The Neuropathic Pain ScaleThe IASP defines neuropathic pain (NP) as:

pain initiated or caused by a primary lesion

or dysfunction of the nervous system

and it is a group of neurological disorders

characterised by chronic pain and typically

includes reports of burning, hyperpathia, and

lancinating pain regardless of aetiology[23].

Peripheral neuropathy is one of the most common

complications of diabetes, and is associated

with long standing periphera l neuropathic pain

affecting the life of a patients with diabetic foot.

The NPS was developed by Galer and Jensen

in 1996 [21] to assess NP based on their clinical

experience of identifying the most frequent

words used by patients with NP to de scribe theirpain. The NPS includes two descriptors of pain

including intensity and unpleasantness, that have

previously been identified as global descriptors

of pain[24,25], and eight descriptors that assess

specific qualities of NP: sharp, hot, dull, cold,

sensitive, itchy, deep and surface pain. Each of

these 10 dimensions has a 0 to 10 NRS, in which

0 is equal to no pain and 10 equals the most

intense pain.

Psychometrics and clinimetricsPsychometrics or clinimetrics is the process of

scientific development and evaluation of an

evidence-based clinical assessment tool, which

assesses the accuracy, internal consistency,

reliability, and validity of a tool[2628]. Although

both terms have been used in the medical literaturesearch, the majority of new developments in scale

construction like new variations of the intraclass

correlation, item response theory, structural

equation modeling, and cognitive theories

are reported in the psychometric literature, so

continued use of clinimetrics not only leads

to confusion and misunderstanding, but cuts

the scale developer off from a long, rich, and

flourishing literature[29]. Hence Streiner has

questioned the use of the term clinimetrics and

suggests that the term psychometrics might bemore useful[29].

Literature reviewValidity

Validity of a measured tool determines whether the

tool truly measures what it claims to measure [30,31],

and it may be achieved by various means, such as by

how the test measures what it is meant to measure

(content validity), by asking the opinion of an

expert group (face validity), by comparing it with

results of other established pain assessment scales

(concurrent validity), by considering whether it is

able to predict pain-related outcomes (predictive

validity) or by questioning whether a test designed

to measure a construct described by a theory really

measures this construct (construct validity)[27].

There are a number of aspects of the NPS design

that suggest it is a valid tool. In 1996, Galer and

Jensen[21] enrolled 288 consecutive patients with

one of four NP conditions: post-herpetic neuralgia

(PHN), reflex sympathetic dystrophy (RSD),

traumatic peripheral nerve injury (TPNI), and

diabetic neuropathy (DN). The authors evaluatedthe predictive validity of the NPS, using analysis of

variance (ANOVA) for each of the 10 descriptors.

The authors concluded that the NPS descriptors

were able to distinguish PHN from RSD, TPNI,

and DN, with PHN being described as more

sharp (F=5.74; P


3/5

ARTICLE

of covariance (ANCOVA) model and responder

analysis were used for the study outcome. The

authors concluded that, relative to placebo,the opioid analgesic produced a statistically

significantly greater decrease in global pain

intensity (P


4/5

THENEUROPATHICPAINSCALEANDITSRELIABILITYANDVALIDITYFORDIABETICNEUROPATHY

ANOVA were performed with treatment (lidocaine

versus phentolamine) and time (immediately

before versus immediately post-treatment) as theindependent variables, and responses to each of

the NPS descriptors as the dependable variables.

The authors concluded that two treatments were

effective, on average, for reducing pain, with most

pain qualities decreasing post-treatment. Lidocaine

was found to be particularly effect ive for unpleasant

and deep qualities of pain, whereas lidocaine

and phentolamine were similarly effective for the

remaining qualities of NP. Moreover, the authors

did mention the limitations of their second study

in generalising the results, as the study was notperformed in a randomised, double-blind fashion

rather the study was done to assess the ability of the

NPS to detect the treatment effect, not to assess

the efficacy of the therapies.

The study by Galer and Jensen[21] not only

indicates high sensitivity and specificity of the

NPS, but also suggests discriminant validity

(an ability for changes to individual dimensions

to reflect specific pain treatments and provide

evidence of their distinct value [34]). Jensen et al[42]

studied the use of the lidocaine patch 5% in

patients with peripheral NP, lower back pain (LBP),

and osteoarthritis with exception of cold pain

in the LBP group. Each of the NPS descriptors

showed significant change after using a lidocaine

patch with relative larger changes in intensity,

unpleasantness, sharp and deep pain, and relatively

smaller changes in cold, sensitive and itchy pain.

The results support the potential use of the NPS for

assessing the patterns of changes in pain qualities

that can be observed after treatment for pain.

Similarly, Galer et al[43] deployed the NPS as the

only pain assessment tool specifically designed tomeasure the distinct components of NP, and Argoff

et al[44], studied the impact of the lidocaine patch

5% on pain associated with PHN, DN and LBP.

Both studies demonstrated the improved sensitivity

and reliability of the NPS in differentiating various

pain states and also in assessing the treatment

outcomes for various pain qualities associated with

given pain states. However, in contrast, Lynch et

al[45] showed adenosine affecting only five of the

NPS descriptors, suggesting that it has a different

treatment mechanism.

The overall usability is important for any

screening tool and to become accepted it needs

to save users time and offer practicality, resulting

in better patient care and cost savings [26]. For the

readability and clarity of the tools, it is important

that users are able to easily understand, interpretand comprehend the questionnaire in order to

self-administer the tool. Galer and Jensen [21]

and Jensen et al[42] addressed these concerns

and provided explanations and instructions,

prompting the patients to note that pain can have

many different qualities and then asked them to

rate their pain according to 10 descriptors of NPS.

However, Backonja and Stacy[23] argued against

this by showing that in the results f rom the NPS

and Neuropathic Pain Questionnaire (NPQ)[46],

the burning pain from NPQ and hot pain fromNPS were essentially the same feeling of hot and

burning, but the frequency and severity of these

two descriptors were different.

ConclusionScreening tools should be easy and quick to

perform, acceptable to the patients and healthcare

workers, and have good reproducibility and valid ity

(Stratton et al, 2004). Precision is necessary,

as patients who are in pain may not want to

spend time, possibly in an uncomfortable position,

completing lengthy charts or questionnaires[47].

However, diagnostic tests are seldom 100%

accurate and both false positive and false negative

results can occur[48].

The NPS is the first pain measure designed

specifically for NP. It assesses various qualities

of NP and has sensitivity and specificity in

relation to NP[21,42,45]. Its short-term test/re-test

and long-term test/re-test reliabilities have been

demonstrated by Rog et al[32] in a study of patients

with MS. They demonst rated that the NPS

could discriminate between different categoriesof NP, and that NPS scores changed in response

to various treatments. However, the NPS cannot

discriminate NP from non-NP, and its ability to

do so remains untested[46].

The literature search has shown that the NPS is a

valid and reliable tool. It captures a large proportion

of the patients own description of their NP and it is

largely free from ambiguity. It can be administered

both by post and in hospital, and it shows both

convergent and discriminant validity with other

commonly-used scales[32]. Thus it is evident that the

NPS is sensitive and specific to the neuropathic pain

experience in the clinical setting, demonstrating a

range of psychometric principles. n

The Diabetic Foot Journal Middle East Vol 1 No 1 2015 15


5/5

ARTICLE

16 The Diabetic Foot Journal Middle East Vol 1 No 1 2015

1. International Association for the Studyof Pain Subcommittee on Taxonomy.Classification of chronic pain syndromesand definitions of pain terms.Pain 1986;3: S1226

2. Fishman S, Ballantyne J, Rathmell JP eds.Bonicas Management of Pain. LippincottWilliams & Wilkins, 2010

3. World Union of World Healing Societies.Principles of Best Practice: MinimisingPain at Dressing-related Procedures. AConsensus Document. MEP Ltd, 2004.Available at: www.wuwhs.org

4. Hareendran A, Bradbury A, Budd J, etal. Measuring the impact of venous legulcers on quality of life. J Wound Care2005; 14(2): 537

5. Rastinehad D. Pressure ulcer pain. JWound Ostomy Cont Nursing 2006;33(3): 2527

6. Cole BE. Diabetic peripheral neuropathicpain: recognition and management. PainMedicine 2007; 8(S2): S2732

7. Duarte RA Classification of pain. In: RKanner ed. Pain Management Secrets.Hasley & Belfus Inc, 1997

8. Douglas V, Way L The assessment ofwound pain: a review. Practice Nursing2006; 17(11): 53242

9. Woo K, Sibbald G, Fogh K et al. Assessmentand management of persistent (chronic)and total wound pain.Int Wound J 2008;5(2): 20515

10. Parsons EP Cultural aspects of pain.Surgical Nurse 1992; 5(2): 1416

11. Kehlet H1, Jensen TS, Woolf CJ. Persistentpostsurgical pain: risk factors andprevention. Lancet 2006; 367(9522):161825

12. Zola I Socio-medical Enquiries:Recollections, Reflections. TempleUniversity Press, 2008

13. Benbow M. A practical guide to reducingpain in patients with wounds. Br JNursing 2009; 18(11): S208 14.Carr E.Factors influencing the experience ofpain. Nursing Times1997; 93(39): 534

14.Carr E. Factors influencing the experienceof pain. Nursing Times 1997; 93(39):534

15. McCaffrey M. Narcotic analgesia for theelderly.Am J Nursing 1985; 85: 2967

16. Melzack R, Katz J. Pain measurement inpersons in pain. In: R Melzack R, WallPD eds. The Textbook of Pain.ChurchillLivingstone, 1999

17. Turk DC, Okifuji A. Assessment ofpatients reporting of pain: an integrated

perspective. Lancet 1999; 353(9166):17848

18. Soon K Acton C. Pain-induced stress: abarrier to wound healing. Wounds UK2006; 2(4): 92

19. Cleeland CS, Ryan KM. Pain assessment:global use of the Brief Pain Inventory.

Ann Acad Med; 1994 23: 12938

20. Bennett M. The LANSS Pain Scale:the Leeds assessment of neuropathicsymptoms and signs. Pain 2001; 92(1):14757

21. Galer BS, Jensen MP. Developmentand preliminary validation of a painmeasure specific to neuropathic pain:The Neuropathic Pain Scale. Neurology1996; 48: 3327

22. Jensen MP, Friedman M, BonzoD, Richards P. The validity of theNeuropathic Pain Scale for assessingdiabetic neuropathic pain in a clinicaltrial. Clin J Pain 2006; 22(1): 97103

23. Backonja MM, Stacey B. Neuropathicpain symptoms relative to overall painrating.J Pain2004; 5(9): 4917

24. Gracely RH, McGrath PA, Dubner R.Validity and sensitivity of ratio scalesof sensory and affective verbal pain

descriptors: manipulation of affect bydiazepam. Pain1978; 5(1): 1929

25. Jensen MP Karoly P Self-Report Scalesand Procedures for Assessing Pain in

Adults. Guilford Press, 1992

26. Feinstein AR. An additional basicscience for clinical medicine: IV. Thedevelopment of clinimetrics. Ann InternMed 1983; 99(6): 8438

27. de Vet HCW, Terwee CB, Bouter LMCurrent challenges in clinimetrics.J ClinEpidemiol2003; 56: 113741

28. Dijkers MP. Psychometrics andclinimetrics in assessing environments.J

Allied Health2004; 32(1): 3843

29. Streiner D. Clinimetrics vs. psychometrics:an unnecessary distinction. J ClinEpidemiol2003; 56: 11425

30. Golafshani N. Understanding reliabilityand validity in qualitative research. TheQualitative Report 2003; 8(4): 597607

31. Schneider G, Wachter M, Driesch Get al. Subjective body complaints asan indicator of somatization in elderlypatients. Psychosomatics 2003; 44(2):919

32. Rog DJ, Nurmikko TJ, Young CAOromucosal tetrahydrocannabinol/cannabidiol for neuropathic painassociated with multiple sclerosis:An uncontrolled, open-label, 2-yearextension trial. Clin Ther 2007; 29(9):206879

33. Selai CE, Trimble MR. Patientsassessments of disability in multiplesclerosis. Most patients have difficultyin rating themselves on visual analoguescales. BMJ 1997; 315(7118): 1305

34. Fishbain DA, Lewis JE, Cutler R etal. Can the neuropathic pain scalediscriminate between non-neuropathicand neuropathic pain? Pain Med 2008;9(2): 14960

35. Victor TW, Jensen MP, Gammaitoni AR etal. The dimensions of pain quality: factoranalysis of the Pain Quality AssessmentScale. Clin J Pain 2008; 24(6): 5505

36. Verhaegen PD1, van der Wal MB,Middelkoop E, van Zuijlen PP. Objectivescar assessment tools: a clinimetricappraisal. Plast Reconstr Surg 2011;127(4): 156170

37. Shrout PE, Fleiss JL Intraclass correlations:uses in assessing rater reliability. PsycholBull1979; 86(2): 4208

38. Jones JM. Reliability of nutritionalscreening and assessment tools.Nutrition 2004; 20: 30711

39. Aaronson N, Alonso J, Burnam A et al.Assessing health status and quality-of-life instruments: attributes and reviewcriteria. Qual Life Res2002; 11: 193205

40. Osterberg A, Boivie J, Thuomas KA.Central pain in multiple sclerosis

prevalence and clinical characteristics.Eur J Pain2005; 9(5): 53142

41. LoBiondo-Wood G, Haber J eds.Nursing Research: Methods and Critical

Appraisal for Evidence-based Practice.Elsevier Health Sciences, 2013

42. Jensen MP, Dworkin RH, GammaitoniAR et al. Assessment of pain qualityin chronic neuropathic and nociceptivepain clinical trials with the NeuropathicPain Scale.J Pain2005; 6(2): 98106

43. Galer BS, Jensen MP, Ma T et al. Thelidocaine patch 5% effectively treatsall neuropathic pain qualities: results ofa randomized, double-blind, vehicle-controlled, 3-week efficacy study withuse of the neuropathic pain scale.Clin JPain2002; 18(5): 297301

44. Argoff CE, Galer BS, Jensen MP et al.Effectiveness of the lidocaine patch 5%on pain qualities in three chronic painstates: assessment with the NeuropathicPain Scale. Curr Med Res Opin 2004;20(2): S218

45. Lynch ME, Clark AJ, Sawynok J. A pilotstudy examining topical amitriptyline,ketamine, and a combination of both inthe treatment of neuropathic pain. Clin JPain2003; 19(5): 3238

46. Krause SJ, Backonja MM. Developmentof a neuropathic pain questionnaire.Clin

J Pain2003; 19(5): 30614

47. Stratton RJ, Hackston A, Longmore D etal. Malnutrition in hospital outpatientand inpatients: prevalence, concurrentvalidity and ease of use of the

malnutrition universal screening tool(MUST) for adults. Br J Nutr 2004; 92:799808

48. Greenhalgh T. How to Read a Paper: TheBasics of Evidence-Based Medicine. 4thedn. Wiley Blackwell, 2010

Precision is necessary,as patients who are inpain may not want tospend time, possiblyin an uncomfortableposition, completinglengthy charts orquestionnaires.

Documents

fj me Malik revised