Digital Pain Mapping and Tracking in Patients With Chronic Pain: Longitudinal Study

Pain trajectories and neuropathic pain symptoms following lung cancer surgery: A prospective cohort study

BACKGROUND

Persistent postsurgical pain (PPSP) after lung cancer surgery is common and current definitions are based on evaluations at a single time point after surgery. Pain intensity and symptoms may however fluctuate and change over time, and be impacted by multiple and shifting factors. Studies of postoperative recovery patterns and transition from acute to chronic pain are needed for further investigation of preventive measures and treatments to modify unfavourable recovery paths.

METHODS

In this explorative study, 85 patients undergoing surgery due to either presumptive or confirmed lung cancer reported pain intensities bi-monthly for 12 months. Pain trajectories during recovery were investigated, using group-based trajectory modelling. Associations with possible risk factors for PPSP, including clinical variables and anxiety and depression score (HADS), were also explored.

RESULTS

A trajectory model containing three 12-month pain recovery groups was computed. One group without PPSP fully recovered (50%) within two to three months. Another group with mild-intensity PPSP followed a protracted recovery trajectory (37%), while incomplete recovery was observed in the last group (13%). Acute postoperative pain and younger age were associated with a less favourable recovery trajectory. More neuropathic pain symptoms were observed in patients with incomplete recovery.

CONCLUSIONS

Three clinically relevant recovery trajectories were identified, based on comprehensive pain tracking. Higher acute postoperative pain intensity was associated with an unfavourable pain recovery trajectory.

SIGNIFICANCE STATEMENT

Understanding the transition from acute to chronic postoperative pain and identifying preoperative risk factors is essential for the development of targeted treatments and the implementation of preventive measures. This study (1) identified distinct recovery trajectories based on frequent pain assessment follow-ups for 12 months after surgery and (2) evaluated risk factors for unfavourable postoperative pain recovery paths. Findings suggest that early higher postoperative pain intensity is associated with an unfavourable long-term recovery path.

Reliability of the Pen-on-Paper Pain Drawing Analysis Using Different Scanning Procedures

INTRODUCTION

Pen-on-paper pain drawing are an easily administered self-reported measure that enables patients to report the spatial distribution of their pain. The digitalization of pain drawings has facilitated the extraction of quantitative metrics, such as pain extent and location. This study aimed to assess the reliability of pen-on-paper pain drawing analysis conducted by an automated pain-spot recognition algorithm using various scanning procedures.

METHODS

One hundred pain drawings, completed by patients experiencing somatic pain, were repeatedly scanned using diverse technologies and devices. Seven datasets were created, enabling reliability assessments including inter-device, inter-scanner, inter-mobile, inter-software, intra- and inter-operator. Subsequently, the automated pain-spot recognition algorithm estimated pain extent and location values for each digitized pain drawing. The relative reliability of pain extent analysis was determined using the intraclass correlation coefficient, while absolute reliability was evaluated through the standard error of measurement and minimum detectable change. The reliability of pain location analysis was computed using the Jaccard similarity index.

RESULTS

The reliability analysis of pain extent consistently yielded intraclass correlation coefficient values above 0.90 for all scanning procedures, with standard error of measurement ranging from 0.03% to 0.13% and minimum detectable change from 0.08% to 0.38%. The mean Jaccard index scores across all dataset comparisons exceeded 0.90.

CONCLUSIONS

The analysis of pen-on-paper pain drawings demonstrated excellent reliability, suggesting that the automated pain-spot recognition algorithm is unaffected by scanning procedures. These findings support the algorithm's applicability in both research and clinical practice.

Digital mapping of shoulder pain in patients with shoulder disorders: a reliability study

INTRODUCTION

Digital body mapping can be used to document and quantify the area and location (distribution) of pain and discomfort and support assessment, monitoring, and treatment in clinical populations. This study determines the test-retest reliability of drawings detailing pain and pins and needles using digital body charts and their relationship to pain intensity and patient-reported shoulder function.

METHODS

Sixty-two participants with shoulder disorder completed pain and pins and needles drawings with test-retest interval of 30 minutes. Pain intensity in the last week and the patient-reported shoulder function questionnaires were completed. Area and radiating extent were determined using customized software. To assess relative and absolute test-retest reliability, the intraclass correlation coefficient (ICC3,1), standard error of measurement (SEM) and minimal detectable change (MDC95) were calculated. Regression analysis evaluated relation between area and radiating extent of pain and pins and needles with patient-reported function questionnaires.

RESULTS

Relative reliability for pain area and radiating extent was excellent (>0.90). Absolute reliability (SEM and MDC95) values for the pain area and radiating extent were 0.20%/34 pixels and 0.57%/94 pixels. Absolute reliability improves for smaller pain areas. Regression analysis revealed the area and radiation extent for both pain and pins and needles are independent constructs to the patient-reported function outcome when adjusted for pain intensity.

CONCLUSIONS

Digital body mapping assessing pain area and radiation extent in patients with shoulder disorders are reliable. The magnitude of absolute reliability suggests other sources of variability on repeat testing in this population. Pain area and radiation extent appear to be independent constructs.

Where is Your Pain? Achilles Tendinopathy Pain Location on Loading Is Different to Palpation, Imaging and Recall Location

OBJECTIVE: To describe and compare pain maps reported during Achilles tendon loading exercises with recall pain location, in people with pain on palpation in their Achilles tendon and tendon pathology on imaging. DESIGN: Cross-sectional analysis of baseline RCT. METHOD: Participants were recruited from a larger Achilles tendinopathy clinical trial. Inclusion criteria were at least 2-month self-reported history of Achilles tendinopathy, midtendon palpation pain, and pathology on ultrasound tissue characterization. Participants were asked to identify their Achilles tendon pain location on a pain map with 8 prespecified locations while at rest prior to loading (recall pain), and subsequently during tendon loading exercises (loading pain). Participants could select multiple locations or select "other" if the locations did not represent their pain. RESULTS: Ninety-three participants were included (93% of participants from a clinical trial). The locations of pain on loading were diverse; all 8 pain locations (and an "other" option) were represented within this sample. Twenty-five percent of participants did not report pain with loading (n = 23 of 93). Of the 70 participants with loading pain, recall pain location differed to loading pain location in 40% (n = 28 of 70) of the participants. CONCLUSION: Palpation pain location, recall pain location, or location of pathology on imaging were not valid proxies for load-related pain in the Achilles tendon. How different pain locations respond to treatment is unknown. Some pathologies (eg, plantaris) have clear pain locations (eg, medial tendon), and assessing pain location may assist differential diagnosis. J Orthop Sports Phys Ther 2024;54(1):1-9. Epub 7 December 2023. doi:10.2519/jospt.2023.12131.

Do metrics derived from self-reported and clinician-reported pain drawings agree for individuals with chronic low back pain?

BACKGROUND

Clinicians commonly use pain drawings to define the spatial extent and location of a person's pain, but limited research has investigated who should perform the drawing.

OBJECTIVES

To establish the inter-rater reliability of pain extent and location derived from three sets of pain drawings for people with chronic low back pain: one self-reported and two clinician-reported. Additionally, convergent validity of pain extent was assessed using the same dataset.

DESIGN

Repeated-measures cross-sectional study.

METHOD

Fifteen patients with chronic low back pain and a pool of eight clinicians were involved to assess the reliability of pain extent and location extracted by self-report and clinician-reported pain drawings. Inter-rater reliability of pain extent was computed using intraclass correlation coefficients (ICC) and Bland Altman analysis. Convergent validity of pain extent was assessed using Spearman's rank correlation. Inter-rater reliability of pain location was assessed using the Jaccard similarity index.

RESULTS

The inter-reliability analysis for pain extent, derived from self-reported and clinician-reported pain drawings, revealed ICC scores ranging from 0.39 to 0.51, all with wide confidence intervals. The mean Jaccard similarity indexes computed for pain location ranged from 0.60 to 0.65. Moderate to good correlation was found for pain extent derived by the sets of pain drawings.

CONCLUSIONS

Inter-rater reliability of pain extent and pain location derived from self-reported and clinician-reported pain drawings is poor in patients with chronic low back pain. The lack of reliability is also confirmed when considering only clinician-reported PDs. The convergent validity analysis of pain extent revealed that the two pain drawing approaches measure a similar construct.

Acceptability, usability and feasibility of experienced sampling method in chronic secondary pain syndromes

Background

In chronic pain syndromes, symptoms can fluctuate and change over time. Standard questionnaires cannot register these fluctuations. Nonetheless, the experience sampling method (ESM) is developed to collect momentary measurements of everyday complaints, tracing fluctuations in symptoms and disabling factors over time. Although valuable information can be collected in this way, assessment may also be a burden. This study aimed to investigate the acceptability, usability, and feasibility of ESM in chronic secondary pain syndromes, in a single-center study in the Netherlands.

Methods

A prospective observational study with repeated measurements was conducted in patients with chronic secondary neuropathic and musculoskeletal pain syndromes, including small fiber neuropathy, spinal cord injury, and rheumatoid disorder.

Results

Thirty-four participants were included and filled in the ESM, of whom 19 were diagnosed with small fiber neuropathy, 11 with spinal cord injury, and 4 with a rheumatoid disorder. The mean age was 54.7 ± 13.9 years (range: 23-77) of whom 52.9% were female. In total, 19 participants filled in the general and user-friendliness evaluation about the acceptability and usability of the ESM. The general evaluation showed no influence of ESM on participants' social contacts (mean 1.47, SD 1.12), activities (mean 1.74, SD 1.44), and mood (mean 1.89, SD 1.59). The answers options of ESM were a good representation of the experiences of participants (mean 4.58, SD 1.77). Regarding feasibility, the overall response rate for answering the beep signals of ESM was 44.5% in total. The missing rate per person varied from 13% to 97% with a median of 54.1%.

Conclusion

The general evaluation and the user-friendliness revealed sufficient outcomes in favor of the ESM application. ESM seems a promising measurement tool to use in secondary chronic pain syndromes.

Quantification of Patient-Reported Pain Locations: Development of an Automated Measurement Method

Patient-reported pain locations are critical for comprehensive pain assessment. Our study aim was to introduce an automated process for measuring the location and distribution of pain collected during a routine outpatient clinic visit. In a cross-sectional study, 116 adults with sickle cell disease-associated pain completed PAIN Report It Ⓡ . This computer-based instrument includes a two-dimensional, digital body outline on which patients mark their pain location. Using the ImageJ software, we calculated the percentage of the body surface area marked as painful and summarized data with descriptive statistics and a pain frequency map. The painful body areas most frequently marked were the left leg-front (73%), right leg-front (72%), upper back (72%), and lower back (70%). The frequency of pain marks in each of the 48 body segments ranged from 3 to 79 (mean, 33.2 ± 21.9). The mean percentage of painful body surface area per segment was 10.8% ± 7.5% (ranging from 1.3% to 33.1%). Patient-reported pain locations can be easily analyzed from digital drawings using an algorithm created via the free ImageJ software. This method may enhance comprehensive pain assessment, facilitating research and personalized care over time for patients with various pain conditions.

Pain provocation tests and clinical entities in male football players with longstanding groin pain are associated with pain intensity and disability

BACKGROUND

Clinical examination of male football players with longstanding groin pain can be considered difficult. Pain provocation tests are used to examine and classify longstanding groin pain into clinical entities as adductor-, iliopsoas-, inguinal-, and pubic-related. It is unknown if pain provocation tests and clinical entities are associated with pain intensity and disability.

OBJECTIVES

To investigate if the number of positive pain provocation tests and clinical entities are associated with pain intensity and disability, measured by the Copenhagen 5-Second Squeeze Test (5SST) and the Copenhagen Hip and Groin Outcome Score (HAGOS), respectively.

DESIGN

Cross-sectional.

METHOD

Forty male football players (age: mean 24 years [SD: 3.2]; height: mean 182 cm [SD: 5.7]; weight: mean 78 Kg [SD: 6.6]) with longstanding groin pain for a median of 8.5 months (IQR: 4-36) were included. The players underwent a bilateral groin examination with 33 pain provocation tests and were classified with clinical entities (0-7) based on the test findings.

RESULTS

The number of positive pain provocation tests (median 10, range 2-23) correlated with pain intensity (5SST: rs = 0.70 [95% CI: 0.50, 0.83]) and disability (HAGOS subscales Sport: rs =-0.62 [95% CI: -0.81, -0.36], Pain: rs = -0.38 [95% CI: -0.69, -0.06], Symptoms: rs = 0.52 [95% CI: -0.73, -0.24], ADL: rs = -0.48 [95% CI: -0.71, -0.18]). The number of clinical entities (median 3, range: 1-7) showed similar but weaker correlations to pain intensity and disability.

CONCLUSIONS

In male football players with longstanding groin pain, the number of positive pain provocation tests and clinical entities shows weak to strong correlations with pain intensity and disability. Consequently, when pain intensity and disability are severe, a higher number of pain provocation tests may be positive, and more clinical entities may be present.

Skin temperature normalizes faster than pressure pain thresholds, pain intensity, and pain distribution during recovery from eccentric exercise

INTRODUCTION

Acute musculoskeletal injuries have diverse symptomatology and a multidimensional recovery process, including changes in swelling, redness, hyperalgesia, and expanded pain distribution. In a small proportion of cases, the tissue heals, although these symptoms persist, reflecting altered peripheral and central pain mechanisms. However, the otherwise healthy multidimensional recovery process following damage and pain is less than clear. The objective was to assess mechanical muscle hyperalgesia, skin temperature, and pain intensity and distribution during the recovery process in response to eccentric exercise in the hamstring muscles.

METHODS

Twenty-four healthy males participated in four sessions (Day-0, Day-2, Day-4, and Day-7). Exercise-induced muscle soreness was induced on Day-0 by five sets of 20 repetitions of an eccentric exercise involving the hamstrings on the dominant leg. Each session included assessments of thermography, pressure pain thresholds (PPTs), pain intensity, and area of exercise-induced pain.

RESULTS

Decreased PPTs (P < 0.005), higher pain intensity (P < 0.001), and a larger area of pain (P < 0.001) were displayed on Day-2 and Day-4 than Day-0. Skin temperature decreased on Day-2 than Day-0 (P < 0.01) and returned to baseline assessments by Day-4, despite lower temperature than the contralateral tight (P < 0.01). Further, there was a positive correlation between pain intensity and area on Day-2 and Day-4 (P < 0.005), but no for changes in skin temperature.

CONCLUSION

Thermographic changes and pain-related variables altered following eccentric exercise demonstrate different recovery times. These results provide insights into potential mechanisms and measures that can be used to assess recovery from exercise-induced damage.

Feasibility and acceptability to use a smartphone-based manikin for daily longitudinal self-reporting of chronic pain

Background

As management of chronic pain continues to be suboptimal, there is a need for tools that support frequent, longitudinal pain self-reporting to improve our understanding of pain. This study aimed to assess the feasibility and acceptability of daily pain self-reporting using a smartphone-based pain manikin.

Methods

For this prospective feasibility study, we recruited adults with lived experience of painful musculoskeletal condition. They were asked to complete daily pain self-reports via an app for 30 days. We assessed feasibility by calculating pain report completion levels, and investigated differences in completion levels between subgroups. We assessed acceptability via an end-of-study questionnaire, which we analysed descriptively.

Results

Of the 104 participants, the majority were female (n = 87; 84%), aged 45-64 (n = 59; 57%), and of white ethnic background (n = 89; 86%). The mean completion levels was 21 (± 7.7) pain self-reports. People who were not working (odds ratio (OR) = 1.84; 95% confidence interval (CI), 1.52-2.23) were more likely, and people living in less deprived areas (OR = 0.77; 95% CI, 0.62-0.97) and of non-white ethnicity (OR = 0.45; 95% CI, 0.36-0.57) were less likely to complete pain self-reports than their employed, more deprived and white counterparts, respectively. Of the 96 participants completing the end-of-study questionnaire, almost all participants agreed that it was easy to complete a pain drawing (n = 89; 93%).

Conclusion

It is feasible and acceptable to self-report pain using a smartphone-based manikin over a month. For its wider adoption for pain self-reporting, the feasibility and acceptability should be further explored among people with diverse socio-economic and ethnic backgrounds.

Visualizing and quantifying spatial and qualitative pain sensations

Similar to the purpose of an infographic, visualizing spatial and qualitative sensations on a body chart is a fast and digestible method for communicating complex information and experiences. Further, digitizing these body charts into an interactive medium creates unprecedented opportunities for collecting extensive data. Moreover, applying simple rule-based algorithms or more advanced machine learning approaches to these charts catapults the quantification and spatiotemporal relations of pain and qualitative pain sensations into a new field ripe for pioneering discoveries.

Digital body mapping of pain quality and distribution in athletes with longstanding groin pain

Groin pain is common in athletes, but remains a challenge to diagnose. Self-reported pain quality distribution may facilitate differential diagnoses. We included 167 athletes with groin pain (≥ 4 weeks). All athletes received a standardized clinical examination. Athletes could choose multiple quality descriptors and intensity, and drew these on a digital body map. Overlay images were created to assess distribution and area visually. Intensity, duration, and qualities were compared between each clinical entity and multiple entities. Top three quality descriptors were electric (22%), pain (19%), and dull/aching (15%). There were no differences in the frequencies of quality descriptors (p = 0.893) between clinical entities. Areas of the mapped qualities were similar between the single clinical entities (χ²(3) = 0.143, p = 0.986) and independent of symptom duration (ρ = 0.004, p = 0.958). Despite a considerable overlap, the mapped pain qualities' distributions appear to differ visually between single clinical entities and align with the defined clinical entities of adductor-related, inguinal-related, and pubic-related groin. In iliopsoas-related groin pain, pain extended more medially. The overlap between the drawn areas underscores a challenge in differentiating groin pain classifications based only on self-reported pain. The prevalence of pain quality descriptors varied and individually do not associate with one particular clinical entity of groin pain.

Pain extent is associated with Central Sensitization Inventory but not widespread pressure pain sensitivity or psychological variables in women with fibromyalgia

OBJECTIVE

To investigate the relationship between pain extent, as a clinical sign of central sensitization, and clinical, psychological, and pressure sensitivity in women with fibromyalgia syndrome (FMS).

METHOD

In this study, 126 females with FMS completed demographic (age, gender, body mass index, height, weight), clinical (pain history, and pain intensity at rest and during daily living activities), psychological (depression and anxiety levels), and neurophysiological [pressure pain threshold (PPT)] assessments. The Central Sensitization Inventory (CSI) was also used to collect self-reported symptoms of sensitization. Pain extent and frequency maps were obtained from pain drawings using customized software. After conducting a multivariable correlation analysis to determine the relationships between variables, a stepwise linear regression model analysis was performed to identify variables associated with pain extent.

RESULTS

Pain extent was positively associated with age (r = 0.17), years with pain (r = 0.27), pain during daily life activities (r = 0.27), and CSI (r = 0.42) (all p < 0.05). The stepwise regression analysis revealed that 27.8% of the pain extent was explained by CSI, age, and years with pain.

CONCLUSIONS

This study found that larger pain extent was associated with self-reported outcomes, i.e. CSI, but not neurophysiological outcomes, i.e. PPTs, of sensitization in women with FMS. Older age and a longer history with pain symptoms were also associated with larger pain extent.

Spatiotemporal patterns of pain distribution and recall accuracy: a dose-response study

OBJECTIVES

Clinical decisions rely on a patient's ability to recall and report their pain experience. Monitoring pain in real-time (momentary pain) may reduce recall errors and optimize the clinical decision-making process. Tracking momentary pain can provide insights into detailed changes in pain intensity and distribution (area and location) over time. The primary aims of this study were (i) to measure the temporal changes of pain intensity, area, and location in a dose-response fashion and (ii) to assess recall accuracy of the peak pain intensity and distribution seven days later, using a digital pain mapping application. The secondary aims were to (i) evaluate the influence of repeated momentary pain drawings on pain recall accuracy and (ii) explore the associations among momentary and recall pain with psychological variables (pain catastrophizing and perceived stress).

METHODS

Healthy participants (N=57) received a low (0.5 ml) or a high (1.0 ml) dose of hypertonic saline (5.8%) injection into the right gluteus medius muscle and, subsequently, were randomized into a non-drawing or a drawing group. The non-drawing groups reported momentary pain intensity every 30-s. Whereas the drawing groups reported momentary pain intensity and distribution on a digital body chart every 30-s. The pain intensity, area (pixels), and distribution metrics (compound area, location, radiating extent) were compared at peak pain and over time to explore dose-response differences and spatiotemporal patterns. All participants recalled the peak pain intensity and the peak (most extensive) distribution seven days later. The peak pain intensity and area recall error was calculated. Pain distribution similarity was determined using a Jaccard index which compares pain drawings representing peak distribution at baseline and recall. The relationships were explored among peak intensity and area at baseline and recall, catastrophizing, and perceived stress.

RESULTS

The pain intensity, area, distribution metrics, and the duration of pain were lower for the 0.5 mL than the 1.0 mL dose over time (p<0.05). However, the pain intensity and area were similar between doses at peak pain (p>0.05). The pain area and distribution between momentary and recall pain drawings were similar (p>0.05), as reflected in the Jaccard index. Additionally, peak pain intensity did not correlate with the peak pain area. Further, peak pain intensity, but not area, was correlated with catastrophizing (p<0.01).

CONCLUSIONS

This study showed differences in spatiotemporal patterns of pain intensity and distribution in a dose-response fashion to experimental acute low back pain. Unlike pain intensity, pain distribution and area may be less susceptible in an experimental setting. Higher intensities of momentary pain do not appear to influence the ability to recall the pain intensity or distribution in healthy participants.

IMPLICATIONS

The recall of pain distribution in experimental settings does not appear to be influenced by the intensity despite differences in the pain experience. Pain distribution may add additional value to mechanism-based studies as the distribution reports do not vary with pain catastrophizing. REC# N-20150052.

Improved User Engagement and Assessment of Treatment Effectiveness in Patients Utilizing a Novel Digital Mobile Health Application During Spinal Cord Stimulation Screening Trials (Preprint)

Background

Patient outcomes and experience during a Spinal Cord Stimulation (SCS) screening trial can have a significant effect on whether to proceed with long-term, permanent implantation of an SCS device for the treatment of chronic pain. Enhancing the ability to track and assess patients during this initial trial evaluation offers the potential for improved understanding regarding the suitability of permanent device implantation as well as identification of the SCS-based neurostimulative modalities and parameters that may provide substantial analgesia in a patient-specific manner.

Objective

In this report, we aimed to describe a preliminary, real-world assessment of a new, real time tracking, smart, device-based digital app used by patients with chronic pain undergoing trial screening for SCS therapy.

Methods

This is a real-world, retrospective evaluation of 13,331 patients diagnosed with chronic pain who used the new “mySCS” mobile app during an SCS screening trial. The app design is health insurance portability and accountability act (HIPAA)-compliant and compatible with most commercially available smartphones (eg, Apple, iPhone, and Android). The app enables tracking of user-inputted health-related responses (ie, pain relief, activity level, and sleep quality) in addition to personal trial goals and a summary of overall experience during the SCS trial. A deidentified, aggregate analysis of user engagement, user-submitted responses, and overall trial success was conducted.

Results

When provided the opportunity, the percentage of users who engaged with the tracking app for ≥50% of the time during their trial was found to be 64.43% (n=8589). Among the 13,331 patients who used the app, 58.24% (n=7764) entered a trial goal. Most patients underwent SCS screening with a trial duration of at least 7 days (n=7739, 58.05%). Of those patients who undertook a 7-day SCS trial, 62.30% (n=3456) engaged the app for 4 days or more. In addition, among all who submitted descriptive responses using the app, health-related improvements were reported by 77.84% (n=10,377) of patients who reached day 3 of the screening phase assessment and by 83.04% (n=11,070) of those who reached trial completion. A trial success rate of 91% was determined for those who used the app (versus 85% success rate for nonusers).

Conclusions

Data from this initial, real-world examination of a mobile, digital-health–based tracking app (“mySCS”), as used during the SCS screening phase, demonstrate that substantial patient engagement can be achieved while also providing for the acquisition of more real time patient-outcome measures that may help facilitate improved SCS trial success.

Pain in the temple? Headache, muscle pain or both: A retrospective analysis

AIM

Headache attributed to temporomandibular disorders and myalgia are two diagnoses included in the diagnostic criteria for temporomandibular disorders (DC/TMD). However, it is not clear if these two diagnoses are different clinical entities given their similar presentation and way in which they are diagnosed, when the myalgia is within the temporalis muscle. The purpose of this retrospective study was to assess the overlap between headache attributed to temporomandibular disorders and myalgia of the temporalis muscle.

METHODS

The charts of 671 patients seeking treatment at the Section of Orofacial Pain and Jaw Function, Aarhus University, Denmark, between January 2015 and February 2020 were screened for a diagnosis of headache attributed to temporomandibular disorders, myalgia of the temporalis muscle, or both.

RESULTS

A total of 89 patients fulfilled the DC/TMD criteria for either headache attributed to TMD, myalgia of the temporalis or both. Of these, two had a diagnosis of headache attributed to TMD, 16 of myalgia of the temporalis, and 71 were diagnosed with both. In 97.3% of the times that headache attributed to temporomandibular disorders was diagnosed, the patient was also diagnosed with myalgia of the temporalis. The Jaccard index was 0.8, indicating a substantial overlap between the two diagnoses. Finally, the overlap of pain location between the two diagnoses was substantial, with a Jaccard index of 0.9.

CONCLUSIONS

In the present study, headache attributed to temporomandibular disorders was almost exclusively diagnosed together with myalgia of the temporalis. Therefore, we propose that headache attributed to temporomandibular disorders and myalgia of the temporalis muscle have more clinical similarities than differences and as such could be considered one single clinical entity. Further studies will be needed to address the clinical consequences of this proposal.