Filipino Version of Penn Facial Pain Scale: Phase 1 Validation Study
Genevieve Lynn Tan Yu, Raymond L. Rosales
Apr 2018 DOI 10.35460/2546-1621.2017-0075

Introduction
Trigeminal neuralgia (TN) or tic douloureux is a chronic, paroxysmal, unilateral neuropathic pain of the fifth cranial nerve. It has been described in literature as early as first century AD by Arateus (1).
Its overall incidence of TN was reported to be at 4.3 – 4.7 per 100,000 persons per year for both genders and was noted to be more common in females with a ratio of 3:2 (age adjusted female 5.9 vs. male 3.4) (1,2). More recent studies done in Europe, however, have shown a significantly higher incidence of TN at 26-28.9 per 100,000 person years (3–5). Mean age of onset is 52-58 years old in its idiopathic form and 30-35 years in those with secondary causes of TN such as demyelinating disease, neoplasms or trauma. TN incidence increases with age in both genders.
TN is mainly a clinical diagnosis where the key feature is the paroxysmal excruciating pain felt within the trigeminal nerve distribution over the maxillary (35%), mandibular branches (30%), both maxillary and mandibular (20%), ophthalmic and maxillary (10%), ophthalmic (4%) and all branches of the trigeminal nerve (1%) (6). Most patients would describe the pain as sharp, superficial, burning, stabbing or electric-like in quality usually of high intensity. These attacks may last for a few seconds to a maximum of 2 minutes with spontaneous remissions but would recur repeatedly. TN can be precipitated by sensory stimulation of trigger zones usually over the nasolabial or intraoral area (7) but may be located within any region of dermatome of the trigeminal nerve. Stimuli can be as simple as light touch, flow of air, talking, drinking or eating. (8,9)
Pain, in general, is associated with a negative impact on patients’ quality of life especially when uncontrolled. Patients have reported changes in physical, psychological and social well-being (10,11). Between neuropathic and somatic pain, neuropathic pain has been found to have higher degree of impairment in patients’ quality of life, mood (anxiety and depression) and sleep (12–14). Because of this, it is prudent to assess patients’ pain and the degree of impairment in TN.
This is a validation study where the Penn Facial Pain Scale (PFPS) was translated to our native Filipino language. The authors believe that adequate pain assessment not only includes pain severity but also the influences it dictates over a person’s life and activities of daily living. It is only with understanding and knowledge that we will be able to treat our patients adequately.
Methodology
- Preparation. The author of the PFPS (Appendix 1), Dr. JY Lee was contacted through email to ask for his permission to translate this scale into the Filipino language. His reply and consent can be seen on Appendix 2.
- Forward Translation. One (1) native speaker and expert in the Filipino language, with experience in translation and cultural adaptation measures, forward translated the scale. The translator was assisted by the investigators for concepts or terms that were not familiar. Appendix 3 contains the forward translated questionnaire.
- Content and face validity with
experts. 10 experts in the field of Neurology were recruited
to review the translated questionnaire. Prior to instituting
the questionnaire, informed consent was taken.
Each item was rated by the experts as to its relevance (1-not relevant, 2- somewhat relevant, 3-quite relevant, 4-highly relevant). Their comments and suggestions were recorded. - Analysis was done using item level content validity index i-CVI - the proportion of experts who agreed that the item is either quite or highly relevant; items with i-CVI higher than 0.80 were accepted, while those lower were subjected to discussion by investigators on whether to include the item or not.
- The forward translated questionnaire was edited according to the suggestions of the experts (Appendix 4). This revised questionnaire was the one used for evaluation of face validity in patients with trigeminal neuralgia.
- Face Validity and Cognitive
Debriefing
Eight patients with TN were recruited using the following inclusion criteria: patients aged 18 years or older, able to speak and to understand the Filipino language suffering from Trigeminal Neuralgia diagnosed by a neurologist. Exclusion criteria were as follows: psychogenic pains, pain associated with mood disorders, patients with substance use, poor cognitive function and those unable to read or write. No one among the TN patients recruited withdrew from the study.
This study was conducted in the University of Santo Tomas Hospital, Clinical Division, Out-patient Department of Neurology and Psychiatry and in the clinics of participating consultants. The study protocal was approved by the hospital Institutional Review Board. Prior to instituting the scales, an informed consent was taken from the participants and their corresponding attending physicians.
All participants were asked to answer the Filipino version of the PFPS. All patients’ general data (age, sex, height, weight, occupation, level of education, duration of symptoms) were taken. Each of the 8 patients answered the edited Filipino questionnaire and was asked the following questions: - Do you have difficulty answering each question?
- If yes, how will you restate them?
- Are the responses difficult to understand?
- If yes, how will you restate them?
- Are the questions relevant to your condition?
- Are the questions offensive / upsetting to you as a patient?
- If yes, how will you restate them?
- Problematic items and/or reports were recorded. Suggestions or alternative wording and phrasing were documented.
- Back Translation. The final Filipino version of the PFPS questionnaire was back translated by another independent native speaker of the Filipino language. The back translated version can be seen on Appendix 5.
- Comparison of the final and back translated PFPS questionnaires. The back translated questionnaire was compared to the original version of the questionnaire by the investigators.
Results
Ten experts in the field of Neurology from the University of Santo Tomas Hospital were recruited to assess the content and face validity of the translated PFPS. Each respondent was tasked to rate each of the items as 1- not relevant, 2-somewhat relevant 3 – quite relevant and 4 – highly relevant. Based on the item level content validity index score (i-CVI), all of the items scored equal or greater than 0.8 and were accepted and maintained in the questionnaire. See table 2 below.
Face validity was also initially evaluated by the experts and their comments and suggestions were recorded (Table 3). For item number 2, there was some confusion regarding the meaning of the statement “Lagay ng damdamin”. The authors opted to rephrase it to “kalagayan ng damdamin” which was clearer. For item number 3, one expert suggested to use “paglalakad” instead of “paglakad” which we adapted. For item number 5, there was a suggestion to change “pakikisama sa ibang tao” to “pakikitungo sa ibang tao” however, the authors deemed that “pakikisama” was a much simpler word which can be understood by patients hence it was retained. For item number 14, we likewise retained the word “pagkonsumo” since “paglunok” would mean swallowing and facial pain would point more to difficulty in opening mouth and pain when food touches the inner portion of the cheeks. The revised Filipino translated PFPS questionnaire can be seen in Appendix 4.
Eight patients with TN were recruited to appraise the face validity of the revised Filipino questionnaire. Cognitive debriefing was done and they were interviewed regarding their understanding of the items, its relevance, on whether they had any suggestions regarding improvement, aptness of response choices, clarity of instructions and whether the statements were offensive or upsetting. Almost all of the TN participants commented that all the items, instructions and response choices were well understood and that there were no changes necessary. Only one TN participant commented that the response choices were hard to understand or “mahirap lang intindihin”. However, she did not have any other suggestions on how to better state the choices (Table 2). We opted to retain the 0-10 (11-item) scale as this was the most commonly used rating system for pain.
The final version of the Filipino translated PFPS questionnaire (Appendix 4) was back translated (Appendix 5) and compared to the original English version. The original PFPS and back translated English versions were therefore found similar.
Discussion
Classical TN is caused by compression of the trigeminal nerve at the root entry zone usually by an aberrant vessel in 80-90% of cases (15,16). The looping and elongation of the intracranial blood vessels that occurs in natural aging increases the chances of vessel contact with the nerve root. Pulsations cause indentations and damages leading to a circumscribed area of demyelination and remyelination (7,15). Electron microscopy of samples taken during microvascular decompressive surgery has shown dysmyelination, juxtaposition of denuded axons, axonal loss and degeneration as well as collagen deposition (17).
A number of other compressive lesions can cause secondary TN such as solid tumours, cysts, saccular aneurysms (18) and arteriovenous malformations. In some cases, primary demyelination (eg. Multiple sclerosis [MS], 1-5%) or changes in neural function by an MS plaque can be the source of the neuralgia (8,15,16).
An infiltrative lesion of the trigeminal nerve, nerve root and gasserian ganglion as well as infarctions over the pons and medulla have also been implicated as sources of TN(15).
The pain ascribed to TN has been attributed to the hyperactivity or abnormal discharges from the Gasserian ganglion. Demyelinated areas of the axons release ectopic signals stimulating the already active fibers and transiently increasing activity in previously electrically silent ones (8). Ephaptic cross-talk between fibers mediating light touch and those involved in pain may account for the precipitation of neuralgia by tactile stimulation of facial trigger zones (so called, Allodynia) (8,15).
TN is mainly a clinical diagnosis and no specific tests are currently used for its diagnosis. A detailed history taking and clinical examination of the patient will clinch the diagnosis and hence, should always be performed (8).
Since pain is the main symptom in TN, generally, the most commonly used scale is the visual analogue scale (VAS). It is an instrument with a 10 cm horizontal line and 2 descriptors at each end representing pain intensity (eg. No pain and worst pain). It is used to estimate pain intensity and can be used to check for efficacy of pain alleviation. Patients then are asked to rate their pain intensity by making a mark on the line representing their pain intensity. The VAS is scored by measuring the distance between the “no pain" end and the patient’s mark. The 11-point numerical scale likewise assesses pain intensity where the patient is asked to grade pain from a scale of 0 (no pain) to 10 (severe pain). Categorical ratings (mild, moderate, severe) of pain intensity may also be used.
Another frequently used measurement tool is the McGill Pain Questionnaire (MPQ) which asks the patient to indicate the sensory, affective, evaluative and miscellaneous aspects of pain. This scale contains 78 descriptors of the pain where the rank value of the descriptor is based on its position in the word set.
In terms of assessing medication effect, the Barrow Neurological Institute Pain Intensity Score rates the pain from I to V by evaluating pain severity along with need and adequacy of medications (19). The other domains of pain and its effect on quality of life can be assessed using different outcome measurements (i.e. use of Beck Depression Inventory for emotional function; Multidimensional Pain Inventory Interference Scale for physical functions; global assessment in change for improvement post treatment among others).
For this study, the PFPS, which is more specific for facial pains, was selected and translated into the Filipino language.
The original Brief Pain Inventory is a simple, self-administered validated scale which has been used for years and has been translated to multiple languages. It was originally developed by Cleeland in 1984 for pain mainly of oncologic in etiology. It was found to be more advantageous compared to the VAS because it can assess pain intensity and degree of interference with lifestyle and functionality (20).
The Penn Facial Pain Scale (Appendix 1), previously Brief Pain Inventory –Facial, is a validated multidimensional tool that contains 18 questions measuring the 3 domains of pain namely: intensity, interference with general activities and face specific pain interference. It was developed and tested by JY Lee et al last 2010 and was published in the Journal of Neurosurgery (21–23).
General Interference with activities of daily living is measured for 7 different activities namely general activities, mood, walking, normal work, relationship with other people, sleep and ability to enjoy life. It is measured using the Likert scale from 0 (“does not interfere”) to 10 (“completely interferes”).
Interference with activities related to the face is also measured using 7 different conditions namely eating, grooming, brushing or flossing teeth, smiling and laughing, talking, opening the mouth and eating hard foods.
Pain intensity is measured in 4 items as pain at its worst, least, average and at present. A Likert number rating scale ranging from 0 (“no pain”) to 10 (“pain as bad as you can imagine”) is also used.
Ease of administration and comparison between assessments, as well as inclusion of face specific activities were essential considerations in the decision for choosing PFPS as a tool for assessing pain of TN hence the impetus to translate the scale into our native language
Conclusion and Limitations of the Study
The final translated Filipino version is similar to the original PFPS and can be used in the evaluation of pain in TN. However, a Phase 2 study regarding reliability should be done ideally prior to utilizing it in clinical setting.
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Conflict of Interest
The authors did not receive any monetary incentives for this study and it is not funded or supported by any pharmaceutical company. The principal investigators have nothing else to disclose.
Acknowledgement
The authors would like to thank Dr. JY Lee, the developer for Penn Facial Pain scale for giving us the opportunity to translate this evaluation tool. We would also like to acknowledge Dr. Venus Rosales and her team of statisticians for helping us from day 1 of protocol writing until the completion of the article and to the expert respondents for sharing their time and knowledge. Our deepest and most sincere gratitude to our patients, you are the heart and essence of our being as doctors and researchers.
Table 1 Methodology
Table 2 Test on the content validity of the forward translated Penn Facial Pain Scale questionnaire among ten experts rating
|
Item Relevance Rating |
I-CVI |
Decision |
|||
Not Relevant |
Somewhat Relevant |
Quite Relevant |
Highly Relevant |
|||
Frequency (%) |
||||||
Circle the ONE number that describes how, during the past week, pain has interfered with your: |
|
|
|
|
|
|
Q1 General activity Pangkalahatang mga Gawain |
0 |
1 (10) |
2 (20) |
7 (70) |
0.9 |
Accepted |
Q2 Mood Lagayan ng damdamin/kalooban |
0 |
2 (20) |
3 (30) |
5 (50) |
0.8 |
Accepted |
Q3 Walking ability Paglakad |
1 (10) |
1 (10) |
4 (40) |
4 (40) |
0.8 |
Accepted |
Q4 Normal work (includes both work outside the home and housework) Regular na Trabaho (kasama ang trabaho sa labas ng tahanan at mga gawaing bahay) |
0 |
0 |
0 |
4 (100) |
1.00 |
Accepted |
Q5 Relations with other people Pakikisama sa ibang tao |
0 |
1 (10) |
4 (40) |
5 (50) |
0.9 |
Accepted |
Q6 Sleep Pagtulog |
0 |
0 |
1 (10) |
9 (90) |
1.00 |
Accepted |
Q7 Enjoyment of life Pamumuhay/Pagsasaya sa Buhay |
0 |
0 |
0 |
4 (100) |
1.00 |
Accepted |
Q8 Eating a meal Pagkonsumo ng pagkain |
0 |
0 |
1 (10) |
9 (90) |
1.00 |
Accepted |
Q9 Touching your face (including grooming) Paghaplos ng mukha (kabilang na ang pag-alaga sa katawan) |
0 |
1 (10) |
0 |
9 (90) |
0.9 |
Accepted |
Q10 Brushing or flossing your teeth Pagsipilyo ng ngipin |
0 |
0 |
2 (20) |
8 (80) |
1.00 |
Accepted |
Q11 Smiling or laughing Pagngiti at Pagtawa |
0 |
0 |
1 (10) |
9 (90) |
1.00 |
Accepted |
Q12 Talking Pagsasalita |
0 |
0 |
0 |
4 (100) |
1.00 |
Accepted |
Q13 Opening your mouth widely Pagbuka ng bibig nang malaki |
0 |
0 |
3 (30) |
7 (70) |
1.00 |
Accepted |
Q14 Eating hard foods like apples Pagkonsumo ng matitigas na pagkain tulad ng mansanas |
0 |
0 |
2 (20) |
8 (80) |
1.00 |
Accepted |
Q15 Circle the ONE number that describes your pain at its WORST in the last week. Bilugan ang bilang na naglalarawan ng PINAKAMALUBHANG antas ng pananakit na naranasan mo sa nakaraang linggo. |
0 |
1 (10) |
1 (10) |
8 (80) |
0.9 |
Accepted |
Q16 Circle the ONE number that describes your pain at its LEAST in the last week. Bilugan ang bilang na naglalarawan ng PINAKABAHAGYANG antas ng pananakit na naranasan mo sa nakaraang linggo. |
0 |
0 |
0 |
4 (100) |
1.00 |
Accepted |
Q17 Circle the ONE number that describes your pain at its AVERAGE in the last week. Bilugan ang bilang na naglalarawan ng KATAMTAMANG antas ng pananakit na iyong naranasan sa nakaraang linggo. |
0 |
0 |
0 |
4 (100) |
1.00 |
Accepted |
Q18 Circle the ONE number that describes your pain RIGHT NOW. Bilugan ang bilang na naglalarawan ng iyong pananakit SA KASALUKUYAN. |
0 |
0 |
0 |
4 (100) |
1.00 |
Accepted |
Overall |
0 |
0 |
0 |
4 (100) |
1.00 |
Accepted |
Table 3. Test on the face validity of the forward translated Penn Facial Pain Scale questionnaire
|
Major comments among ten experts |
Major comments by eight patients |
Circle the ONE number that describes how, during the past week, pain has interfered with your: |
|
|
Q1 General activity Pangkalahatang mga Gawain |
No modification required |
No modification required |
Q2 Mood Kalagayan ng damdamin/kalooban |
One expert commented “what does this mean?” |
No modification required |
Q3 Walking ability Paglalakad |
One expert suggested to use “paglalakad” |
No modification required |
Q4 Normal work (includes both work outside the home and housework) Regular na Trabaho (kasama ang trabaho sa labas ng tahanan at mga gawaing bahay) |
No modification required |
No modification required |
Q5 Relations with other people Pakikisama sa ibang tao |
One expert suggested to rephrase the question to “Pakikitungo sa ibang tao?” |
No modification required |
Q6 Sleep Pagtulog |
No modification required |
No modification required |
Q7 Enjoyment of life Pamumuhay/Pagsasaya sa Buhay |
No modification required |
No modification required |
Q8 Eating a meal Pagkonsumo ng pagkain |
No modification required |
No modification required |
Q9 Touching your face (including grooming) Paghaplos ng mukha (kabilang na ang pag-alaga sa katawan) |
No modification required |
No modification required |
Q10 Brushing or flossing your teeth Pagsipilyo ng ngipin |
No modification required |
No modification required |
Q11 Smiling or laughing Pagngiti at Pagtawa |
No modification required |
No modification required |
Q12 Talking Pagsasalita |
No modification required |
No modification required |
Q13 Opening your mouth widely Pagbuka ng bibig nang malaki |
No modification required |
No modification required |
Q14 Eating hard foods like apples Pagkonsumo ng matitigas na pagkain tulad ng mansanas |
One expert suggested to rephrase the question to “Paglunok?” |
No modification required |
Q15 Circle the ONE number that describes your pain at its WORST in the last week. Bilugan ang bilang na naglalarawan ng PINAKAMALUBHANG antas ng pananakit na naranasan mo sa nakaraang linggo. |
No modification required |
No modification required |
Q16 Circle the ONE number that describes your pain at its LEAST in the last week. Bilugan ang bilang na naglalarawan ng PINAKABAHAGYANG antas ng pananakit na naranasan mo sa nakaraang linggo. |
No modification required |
No modification required |
Q17 Circle the ONE number that describes your pain at its AVERAGE in the last week. Bilugan ang bilang na naglalarawan ng KATAMTAMANG antas ng pananakit na iyong naranasan sa nakaraang linggo. |
No modification required |
No modification required |
Q18 Circle the ONE number that describes your pain RIGHT NOW. Bilugan ang bilang na naglalarawan ng iyong pananakit SA KASALUKUYAN. |
No modification required |
No modification required |
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