Physical therapist clinical reasoning and classification inconsistencies in headache disorders: a United States survey

ABSTRACT

Objective: The purpose of this study was to investigate the decision-making processes of physical therapists relating to evaluation and categorization of patients with headaches, including consistency with criteria proposed by the International Headache Society (IHS).

Methods: A national online survey was distributed in cooperation with the Academy of Orthopaedic Physical Therapy of the American Physical Therapy Association. Three hypothetical patient case vignettes featuring headache disorders were used as assessment instruments. Additionally, data on physical therapist education, clinical experience, manual therapy training, self-efficacy, and familiarity & consistency with IHS criteria were collected. Physical therapist identification and valuation of clinical features of headache disorders were also examined in the decision-making processes.

Results: Among the 384 respondents, 32.3% classified the tension-type headache case consistent with IHS criteria. The cervicogenic and migraine headache cases were classified at 54.8% and 41.7% consistent with IHS categories, respectively. Experienced clinicians and those with formal manual training categorized patient presentations with greater consistency. Clinician familiarity with IHS classification criteria was low with 73.6% collectively somewhat and not familiar, while 26.4% of physical therapists were self-described as very or moderately familiar.

Discussion: Clinicians’ headache categorization was significantly affected by symptom misattribution and weighting of individual examination findings. Weighting by practitioners of clinical features varied markedly with greatest emphasis being placed on detailed manual examination procedures, including passive intervertebral movements. Inconsistencies in valuation of clinical features in headache categorization suggest a need for further formal education in physical therapy educational curricula and in post-graduate education, including of IHS criteria and classification.

Level of Evidence: 2a

Introduction

Headache disorders are among the most common health conditions and are the most prevalent pain disorder, affecting approximately 66% of the global population[1]. Estimates are that between 1.7% and 4% of the world’s adult population experiences recurrent headaches, defined as headaches on 15 or more days every month [2]. As a result, headache disorders are the third leading cause of disability among the world’s adult population, while migraines alone are the seventh leading cause of disability[3]. Nearly 60 million Americans experience at least one severe headache each year, while fewer than half of these individuals receive a formal diagnosis, representing a significant health concern [4,5]. Headache disorders have a profound economic impact on the United States health-care system, accounting for greater than $31 billion in direct and indirect economic costs[6]. Headaches are often managed by a variety of pharmacological interventions including analgesics, anticonvulsants, antidepressants, triptans, and beta-blockers. While drug treatments are successful for a significant proportion of sufferers, physical therapy is a frequently used alternative or complementary treatment for several headache disorders [7–11].

In 1990, the International Headache Society (IHS) developed a classification system to aid all clinicians in the diagnosis and management of headache disorders. Per the IHS, headaches are classified as primary or secondary headaches based on the patient’s clinical presentation and associated symptoms. Primary headaches are proposed to result from disorders of the nervous system and consist primarily of three types of headache: migraines, tension-type headaches, and trigeminal autonomic cephalalgias[12]. In contrast, secondary headaches result from conditions affecting the nervous system, such as trauma to the head and/or neck, vascular disorders, medication use, infection, or musculoskeletal abnormalities. Cervicogenic headache is one of the most common secondary headaches, comprising 15–20% of the headache population and is a leading cause of disability; including lost time from work, impact on household and social activities, frequent use of analgesics, and severity of depressive symptoms [13–17]. Cervicogenic headaches often result from a mechanical disorder of the upper cervical spine (C1-C3) due to the intimate relationship between the vertebral segments and the trigeminal nerve nuclei, resulting in hemicranial pain [15,18]. In addition, cervicogenic headaches are also associated with tenderness to palpation of cervical spine structures and reduced function of the cervical spine musculature [19–21]. Other features of cervicogenic headache include trigger points causing referred pain to the head and/or neck [22,23], dizziness [24,25], photophobia, phonophobia, sleep disturbance, psychological distress, and an overall decreased quality of life [14,26].

Physical therapists frequently manage individuals experiencing cervicogenic headaches through manual therapy and targeted exercises aimed at reducing the patient’s pain, increasing cervical range of motion (ROM), and improving the function of the cervicoscapular musculature [27–29]. Due to the overlap in symptomatology and varying clinical presentations, however, cervicogenic headaches are frequently misdiagnosed as other headache types, most notably migraines and tension-type headaches [15,30,31]. As a result, misdiagnoses are estimated to occur in up to 50% of patients experiencing chronic headaches within the primary care setting [32–34]. Misdiagnosis of headache disorders may have serious consequences due to the possibility of potentially serious origins of headaches. Headache as the first symptom of serious pathology has been well documented, most notably cerebrovascular accident, brain tumor, encephalitis and meningitis, subarachnoid hemorrhage, temporal arteritis, and cervical artery dissection [35–39]. In order to accurately classify patients with headache disorders and make appropriate decisions regarding patient management, physical therapists should appreciate the often-complex nature of the patient’s symptoms. Despite the current body of knowledge regarding classification and management of headache disorders, practicing physical therapists use a variety of approaches during the examination and treatment of patients experiencing headache disorders [28,40–46].

Relatively little evidence exists pertaining to physical therapist management of patients with headache disorders from a primary care or broader management perspective [45,47–49]. This study sought to examine the clinical decision-making processes behind physical therapist management of patients with headache disorders, to identify potential professional practice factors enabling categorization of headache disorders consistent with IHS criteria, and assess judgments regarding patient treatment or referral to another provider.

Methods

Study design

The present study involved distribution of a cross-sectional, electronic survey with data collection completed May through August of 2017. Participation eligibility required electronic informed consent upon survey initiation. The study was approved by the University of Kentucky Institutional Review Board (IRB) and distributed by the Kentucky Physical Therapy Association (KPTA) and the Academy of Orthopaedic Physical Therapy (AOPT–previously Orthopaedic Section) within the American Physical Therapy Association (APTA). The AOPT represents approximately 20,000 members with interest in management of patients with musculoskeletal disorders. A 25-question electronic survey was constructed, consisting of four sections. Section one gathered professional profile information such as years of clinical experience, specific advanced certifications obtained, and percent of patient caseload consisting of headache-type presentations. Section two consisted of three hypothetical case vignettes presenting in the outpatient physical therapy setting, using clinical features consistent with the IHS classification system (summarized in Appendix 1). The pilot survey was distributed to six physical therapists for review and final revision prior to survey launch. A pain diagram depicting symptom location for each case vignette subject was also included. This section requested respondents to state their proposed headache classification (based on information provided) and accompanying clinical reasoning. Section 3 further investigated how respondents allocated importance of certain clinical presentation features pertaining to their respective prior answers. A list of 16 specific clinical features spanning from location/pattern of the head pain to systemic or constitutional comorbidities was presented. Respondents rated these examination aspects using a Likert importance scale from −2 to +2 (−2 representing high importance of that certain finding to be absent/negative, +2 representing high importance of that certain finding to be present/positive, and 0 representing the finding has no diagnostic value/non-contributory). Lastly, section four was comprised of two questions pertaining to the respondent’s awareness with the International Headache Society’s (IHS) Headache Classification System. Due to survey content and the patient population of interest, physical therapists practicing in the outpatient orthopedic setting, potentially providing primary care, were recruited for inclusion via email link. Inclusion criteria required respondents to be a licensed physical therapist and a member of either the KPTA or the AOPT of the APTA. Respondents were automatically excluded if they were physical therapist assistants or physical therapy students.

Procedure

Survey data collection utilized Qualtrics® (Seattle, WA & Provo, UT, USA). A link to the survey was first distributed through the KPTA for a total of 6 weeks between May and July 2017. The survey was also distributed to members of the AOPT of the APTA (who met the inclusion criteria) via a separate email invitation on 18 July 2017. Data collection was closed 2 weeks later due to cessation of responses.

Statistical analysis

All statistical analyses were performed using SPSS version 23 (IBM, Armonk, NY, USA). Descriptive statistics were gathered using simple counts and frequencies to demonstrate the population represented in the study. Pearson Chi-Square analyses were utilized for analysis of categorical data to determine classification consistency between clinicians and IHS classification system for each headache case vignette. A single response for the hypothetical cases aligned with the IHS criteria as designated by the investigators was determined to be consistent with the IHS classification system. Other single responses were designated as inconsistent with the IHS classification system. Respondents also had the option of selecting more than a single response of classification (a mixed headache) for which partial consistency was designated. Additionally, cross-tabulations were performed to analyze relationships between practitioner professional profile attributes, valuation of specific clinical features, and IHS classification consistency. Specific practitioner attributes analyzed were years of clinical experience, advanced practice certifications/credentials, and level of familiarity with the IHS classification system.

Results from cross-tabulations were created into simple counts and frequencies. Pearson Chi-Square analyses were also performed for each cross-tabulation relationship. For all statistical analyses, 95% confidence intervals were applied, and p values were reported. A p value of <.05 was used for all analyses to determine statistically significant differences.

Results

Of the surveys distributed nationally to practicing physical therapists, 384 initiated the survey. Due to the inclusion criteria, 19 responses were excluded due to practice setting, leaving 365 respondents’ data available to analyze. Respondent completion rates declined throughout survey duration, which required an average of 15 continuous minutes to complete. A resume feature allowed respondents to save progress; therefore, completion was not required in one sitting. The specific response rates for the case vignettes were in sequence: 235 (64.4%), 188 (49.0%), and 163 (42.4%), respectively. Of the 365 included initial responses, 129 (35.3%) completed the entire survey. Missing values were coded as separate numbers to eliminate skewed results. Data from partially completed surveys were recorded and analyzed for the sections completed and are, therefore, represented in the reported results. Sections not completed were coded as separate values and were not included in data analysis.

All included participants were required to be licensed physical therapists in the United States who primarily practice in the outpatient setting. Table 1 illustrates the descriptive statistics of the study participant demographics. The results of the frequencies for headache classification consistency with the IHS system by the participants were 54.8%, 32.3%, and 41.7% for cervicogenic, tension-type, and migraine headache, respectively (see Table 2).

Table 1.

Participant professional profiles.

Clinical Experience	1–3 Years		4–6 Years		7–9 Years		10–13 Years		14–17 Years	18–20 Years	20+ Years
	80		44		44		45		33	15	106
Advanced Practice Credentials	CCS	ECS	GCS	NCS	OCS	PCS	SCS	WCS	CLT	FAAOMPT	CSCS	ATC
	1	1	6	1	173	0	10	0	8	27	33	13
Manual Therapy Training	McKenzie			Maitland			Mulligan		Norwegian		Osteopathic
	24			44			10		8		21
Patients Presenting with Headache Symptoms	0%			1–20%			21–40%		41–60%	61–80%	>81%
	7			321			29		5	2	0

CCS: Cardiovascular & Pulmonary Certified Specialist; ECS: Clinical Electrophysiologic Certified Specialist; GCS: Geriatric Certified Specialist; NCS: Neurologic Certified Specialist; OCS: Orthopedic Certified Specialist; PCS: Pediatric Certified Specialist; SCS: Sports Certified Specialist; WCS: Women’s Health Certified Specialist; CLT: Certified Lymphedema Therapist; FAAOMPT: Fellow in the American Academy of Orthopedic Manual Physical Therapists; CSCS: Certified Strength & Conditioning Specialist; ATC: Certified Athletic Trainer.

Table 2.

Consistency of headache categorization with IHS classification criteria.

Tension-type headache	32.3%
Cervicogenic headache	54.8%
Migraine headache	41.7%

A separate analysis was performed on the classification consistency of the three headache cases that utilized a point system in regard to how respondents completed each case vignette question. The point system was as follows: 3 points for respondents who solely answered with a response consistent with the appropriate headache type, 1 point for those who responded with the appropriate headache type with an additional inconsistent headache type, and 0 points for those concluded with a response that did not include an answer consistent with the designated headache type. The results of the frequency point breakdown were as follows (reported in 3,1,0-point order): Tension-type: 32.3%, 20.9%, 46.8%; Cervicogenic: 54.8%, 21.8%, 23.4%; and Migraine: 41.7%, 16.0%, and 42.3%. A description of the results utilizing a relative point system was intended to allow for an expanded representation of decision-making in that clinicians may not have the single headache typified or cause determined at the first visit but may have enough information to initiate treatment toward clarification-based patient presentation and detailed examination findings.

Results of the frequencies produced by the cross-tabulation between headache classification consistency of the three case vignettes and years of clinical experience demonstrated clinicians who have practiced 20 or more years had the greatest consistency percentage with the IHS classification system for the tension-type headache, cervicogenic headache, and migraine headache cases at 25.0%, 34.0%, and 30.9%, respectively. These frequencies, in addition to the other years of clinical experience cohorts, are depicted in Figure 1. The years of clinical experience group who presented the greatest within-group percentage for tension-type, cervicogenic, and migraine headache cases were as follows: 4–6 and 10–13 years with 41.9%, 14–17 years with 60.0%, and 14–17 years of experience at 55.0%, respectively.

Figure 1.

Consistency of headache categorization versus years of clinical experience.

The cross-tabulation relationship between headache classification consistency and familiarity level of IHS guidelines exhibited that 26.4% of respondents categorized themselves as ‘familiar’ with the IHS classification system guidelines. Figure 2 illustrates findings from this cross-tabulation with relationships of unfamiliar and correct respondents.

Figure 2.

Consistency of headache categorization versus familiarity with IHS criteria.

A cross-tabulation between agreement with the IHS classification system and classification accuracy for the three headache case vignettes was investigated. The results demonstrated that of the participants that agreed with the IHS classification system, for the tension-type headache case, 45.5% were consistent with IHS classification. In the cervicogenic case, 58.4% were consistent and, in the migraine headache case, 40.3% were consistent with the IHS classification guidelines. These data are provided in Figure 3.

Figure 3.

Consistency of headache categorization versus agreement with IHS criteria.

A cross-tabulation and frequency were performed on the relationship between participants with advanced practice credentials (i.e. Orthopedic Certified Specialist, Fellow of the American Academy of Orthopaedic Manual Physical Therapists) and headache classification consistency with the IHS system of the three case vignettes compared to participants without these credentials. The results demonstrated for the tension-type, cervicogenic, and migraine headache cases those with advanced practice credentials overall were at 30.5%, 55.9%, and 37.5% accuracy, while those without advanced practice credentials were found to be 34.6%, 53.5%, and 46.7%, respectively. These differences were not statistically significant and effect sizes were small, r = 0.08, r = 0.09, r = 0.09, respectively.

Valuation of various clinical presentation features was also investigated for each of the tension-type, cervicogenic, and migraine headache case vignettes. The results demonstrated that for the tension-type headache case, ‘location/pattern of the head pain’ was considered most important/critical to be present with 62.9% stating this, the greatest proportion of responses coming from the 20+ years of clinical experience cohort (30.1%). The examination finding chosen most important to be absent was ‘other symptoms/signs of possible neurological origin’ at 22%, the greatest proportion coming from the 20+ years of clinical experience cohort (31.6%). The results demonstrated that for the cervicogenic headache case, ‘precipitation by active neck movement or positioning’ was considered the most important/critical to be present with 81.9% overall stating this, the greatest proportion coming from the 20+ years of clinical experience cohort (30.1%). The examination finding chosen most important to be absent or negative was ‘ingested stimuli related to pain onset (food or drink)’ at 22.5%. Lastly, results demonstrated for the migraine headache case, ‘visual or auditory phenomena (photophobia, phonophobia, or other visual or auditory perception)’ was cited as most important to be present at 71.8%, the greatest proportion coming from the 20+ years of clinical experience cohort (33.9%). The examination finding chosen most important to be absent or negative was ‘specific manual examination results’ at 15.4%. Table 3 demonstrates the top three answers between all respondents for both, important to be positive and negative in examination findings of the three headache cases.

Table 3.

Individual valuation of headache clinical features.

	Tension-type headache	Cervicogenic headache	Migraine headache
Most important examination findings to be positive/present	Location/pattern of head pain (62.9%). Temporal pattern of the pain (49.2%) Specific manual examination results (39.4%).	Precipitation by neck active movement or positioning (81.9%). Limitation of active neck mobility (80.4%). Specific manual examination results (76.8%).	Visual or auditory phenomena (71.8%). Environmental or physical factors related to pain onset (55.8%). Nausea and/or dizziness (51.9%).
Most important examination findings to be negative/absent	Other symptoms/signs of possible neurological origin (22.0%). Ingested stimuli related to pain onset (18.2%). Visual or auditory phenomena (17.4%).	Ingested stimuli related to pain onset (22.5%). Other signs/symptoms of possible neurological origin (21.7%). Visual or auditory phenomena (21.0%).	Specific manual examination results (15.4%). Limitation of active neck mobility (13.5%). Precipitation by neck active movement or positioning (12.8%).

Additional items included but not cited above: responsiveness to medication (prescription & over-the-counter); perception of associated or neighboring pain in the neck, shoulder, or upper extremity; history of cervical/head trauma; imaging results; laboratory results; systemic or constitutional co-morbidities.

Discussion

Evaluation and categorization of headache disorders present a significant challenge to physical therapists practicing in the outpatient setting as primary care providers. This study is the first to examine the clinical reasoning processes behind physical therapy management of patients with headache disorders. Overall, clinicians’ performance in classifying patients with a tension-type, cervicogenic, or migraine headaches consistent with IHS criteria in this sample was low at 32.3%, 54.8%, and 41.7%, respectively. After analyzing the relationship between the clinicians’ professional profiles and headache categorization, years of clinical experience and formal manual therapy training were associated with improved consistency with IHS classification criteria for cervicogenic headache, but not migraine or tension-type headache. Previous studies regarding the cervical spine have examined the effects that clinical decision-making and various manual therapy approaches have on patient outcomes in individuals with neck pain [50,51]. Hahn et al. [51] found that physical therapists who had undergone post-graduate training and obtained post-graduate professional credentials had a significant bias towards their advanced training during the evaluation and treatment of individuals with cervical spine dysfunction, which might explain the differences in weighting of specific examination findings observed in the present study. This study is, however, the first to attempt to capture broad cross-sectional data to make similar comparisons between clinicians’ professional profiles and categorization, while analyzing other trends in reasoning of headache disorders.

There are several possible explanations for the relatively low consistency observed between headache categorization among physical therapists and the classification criteria developed by the IHS. Familiarity with IHS criteria among practitioners appears to be low with only 26.4% reporting being either very or moderately familiar, suggesting a need for greater practice knowledge consistent with demands for the primary care status of physical therapists. Although no data exist regarding the amount of information on headache disorders that individuals receive as part of their physical therapy education, the Commission on Accreditation in Physical Therapy Education (CAPTE) does not explicitly include headache disorders in its criteria for physical therapy program accreditation[52]. A recent systematic review examining the effectiveness of various interventions used by physiotherapists in the treatment of patients with migraines, tension-type headache, and cervicogenic headache suggested that inadequate use of headache classification criteria significantly affects the outcome in patients with chronic headache[48]. As primary contact clinicians, that physical therapists be familiar with consensus-derived guidelines, such as the IHS classification criteria, and be able to utilize these resources to guide patient management decisions is critical. The results of the present study suggest that further formal education and training in institutional curricula and in post-graduate training may be necessary to improve clinical decision-making and classification of patients with headache disorders.

Another possible explanation for the inconsistency of headache categorization among inexperienced practitioners is their ability to recognize patterns of signs/symptoms. Pattern recognition is the ability to recognize a clinical problem based on the patient’s subjective report or examination findings and is frequently utilized by physical therapists in the outpatient setting [53–56]. Pattern recognition, however, develops over years of clinical experience[57], and may be particularly challenging with presentations of remarkable overlap of clinical features and relatively low clinical frequency. This confluence of factors may partially explain the disparity in headache classification between experienced and novice clinicians observed in this study.

More importantly, however, the valuation of patient history elements and specific examination findings among physical therapists practicing in the outpatient setting, particularly those who have obtained advanced professional credentials or have undergone formal manual therapy training, suggests a different perspective in approach to examination and classification of patients with headache disorders compared to physicians. Although there are similarities between this criterion and the weighting of specific examination findings observed in the present study, the IHS criteria exclude certain aspects of the clinical examination that physical therapists often rely upon when classifying patients with headache disorders. Arguably, the most notable exclusion from the newly updated IHS criteria is the results of detailed manual examination of the cervical spine. A comparison between the IHS classification criteria and the Neck Pain: Clinical Practice Guidelines is shown in Table 4. The IHS criteria for cervicogenic headache include clinical and/or imaging evidence of a disorder or lesion within the cervical spine or surrounding soft tissues but does not specifically mention manual assessment techniques commonly performed by physical therapists such as passive intervertebral movements (PIVMs). In contrast, the updated Neck Pain: Clinical Practice Guidelines emphasize the specific manual examination results in their recommendations for categorization of an individual meeting the criteria for the Neck Pain with Headache subclassification[58]. Additionally, a positive imaging finding has been reported in only 0.4% of patients with isolated, nontraumatic headache, which further supports the importance of the clinical examination in the differential diagnosis of headache disorders[59]. The contrast between these two recommendations suggests fundamentally different perspectives on the value of detailed manual examination of the cervical spine in the evaluation of patients with headaches.

Table 4.

IHS classification criteria [5] comparison with APTA’s clinical practice guidelines for neck pain[27].

IHS Classification Criteria for Cervicogenic Headache

Neck Pain with Headache

Any headache fulfilling criterion C. Clinical and/or imaging evidence of a disorder or lesion within the cervical spine or soft tissues of the neck, known to be able to cause headache. Evidence of causation demonstrated by at least two of the following: Headache has developed in temporal relation to the onset of the cervical disorder or appearance of the lesion. Headache has significantly improved or resolved in parallel with improvement in or resolution of the cervical disorder or lesion. Cervical range of motion is reduced and headache is made significantly worse by provocation maneuverers. Headache is abolished following diagnosis blockade of a cervical structure or its nerve supply. Not better accounted for by another ICHD-3 diagnosis.

Common symptoms: Noncontinuous, unilateral neck pain and associated (referred) headache. Headache is precipitated or aggravated by neck movements or sustained positions/postures. Expected exam findings: Positive cervical flexion-rotation test. Headache reproduced with provocation of the involved upper cervical segments Limited cervical ROM. Restricted upper cervical segmental mobility. (E)Strength, endurance, and coordination deficits of the neck muscles.

Differences in execution and valuation of physical examination findings in clinical reasoning by physical therapists in contrast to physicians may underlie a difference in patient assessment and, thus, in practice. A potential underlying contributor to this is the decreased emphasis on the physical examination in medical education and practice, which has been well documented for approximately two decades [60–65]. While detailed spinal palpatory or movement assessment may not routinely be performed by physicians, the information provided therein may be critical to the management decisions required for patients presenting with headache symptoms. The IHS criteria for classification of cervicogenic headache contain an allusion to mechanical factors relating to neck movement, but specific symptom provocation or reduction are not well delineated [12,66].

The utilization of PIVMs has been criticized because of several studies reporting low inter-rater reliability and the diagnostic value therein questioned [67–72]. Detailed analysis of these studies, however, yields several methodological issues and the disintegration of these procedures from common clinical contexts [73,74]. The studies demonstrating higher levels of inter-rater reliability are of greater methodological quality [75,76] and introduction of appropriate clinical contexts has resulted in higher reliability values[77]. Evidence exists revealing that aberrations of spinal PIVMs are detectable upon examination, particularly when supplemented with provocation of the concordant pain described by the patient [78–81]. The overall preponderance of clinical evidence of detailed passive motion examination of the cervical spine is sufficient for its inclusion into current physical therapy clinical practice guidelines with particular value in identification of cervicogenic headache[58].

Thus, decision-making toward management of patients presenting with headache symptoms can be substantively informed by detailed movement assessment, including PIVMs of the cervical spine. These assessment procedures may be contributory for their negative as well as positive findings as the absence of significant results from the cervical spine movement exam, particularly the upper segments, may significantly reduce the probability of cervicogenic headache in the clinical reasoning process. Such examination procedures and the interpretation of the derived results along with other exam data are well within the purview of physical therapists.

A factor potentially contributing to the challenge in accurate categorization of headache presentation in patients and subsequent management that must be considered is elevated activity of central pain mechanisms. Central sensitization has been identified as present in numerous headache types [82–90]. Extraordinary tenderness to palpation, lowered pain-pressure thresholds, mechanical allodynia, and hyperalgesia have been described by several investigators with headaches of various etiologies [82–90]. Findings such as tenderness, either pericranial or upper cervical, are, thus, nonspecific and may contribute relatively little toward accurate classification. Kinesiophobia, typically associated with musculoskeletal disorders including neck pain, has also been identified in migraine headaches and orofacial pain syndromes [91–94]. Thus, the stimulus-response for provocation and reduction of headaches typically considered very important in diagnosis/classification, may be disordered or disproportionate, complicating the identification of key criteria and subsequent clinical reasoning by practitioners of all disciplines. The presence of kinesiophobic behaviors and elevated central pain mechanism activity in patients with headache disorders are associated with an increased risk of chronicity and a less favorable prognosis [95,96]. Physical therapy intervention emphasizing patient education has been shown to reduce pain catastrophizing and fear-avoidance behaviors in patients with migraine and chronic headache disorders [91,97–99]. Therefore, the identification of heightened central pain mechanism activity in patients with migraine and other chronic headaches must still be considered and may assist in accurate categorization of headache disorders[94]. The importance of a thorough history and clinical examination along with a well-reasoned and cautiously interpreted classification result, therefore, becomes critical in management of patients with headache disorders, particularly those with persistent pain. The information gathered during the initial and subsequent patient interactions by a physical therapist with a patient may be especially valuable in navigating the complex clinical reasoning of correct headache classification and management.

The limitations of this study are acknowledged in context as follows. The three patient case vignettes were developed using information from the IHS classification criteria and other available literature regarding signs and symptoms, pain patterns/diagrams, precipitating factors, and expected examination findings. Information about the patients’ ‘comparable signs’ or ongoing reassessment, however, was purposefully excluded to better examine the clinician’s initial clinical reasoning within a hypothetical first patient visit only. Another limitation of the present study is the irregularity with which respondents answered the questions concerning weighting of specific examination findings. As stated previously, a Likert importance scale was utilized for these questions to analyze the relationship between individual weighting of examination findings and consistency with the IHS classification criteria. The respondents, however, infrequently chose the option stating, ‘important/critical to be absent/negative’ despite as Kaniecki [31] states, ‘the IHS classification criteria characterizes tension-type headache by the absence of these features.’ Furthermore, although this study had a large number of participants initially, only 35.3% of those eventually completed the survey.

Conclusion

Headache disorders are common presentations encountered by physical therapists practicing in the outpatient setting. Despite their prevalence, consistency of headache categorization with IHS headache classification criteria by physical therapists is relatively low as suggested by the sample of subjects in this survey. This study also suggests that physical therapists approach examination and categorization of patients with headache disorders from a different perspective than other health-care practitioners, placing greater emphasis on manual examination of the cervical spine to guide patient management decisions. As primary care providers, physical therapists should be familiar with consensus-derived patient management guidelines, including the IHS Classification System. Thus, formal education and training inclusive of IHS classification criteria with consideration of additional information within the purview of physical therapist practice may improve clinical decision-making and subsequent management of patients with headache disorders.

Biography

Philip C. Dale, PT, DPT, is a full-time clinician with Kentucky Orthopedic Rehab Team (KORT) in Lexington, KY. He earned his Doctor of Physical Therapy (DPT) degree from the University of Kentucky in 2018. He also received a Bachelor of Science in Exercise Science from UK in 2014. He is a member of the American Physical Therapy Association (APTA) and American Academy of Orthopaedic Manual Physical Therapists (AAOMPT), where he has had the opportunity to present his doctoral research at both state and national conferences. His clinical interests include general orthopedics, manual therapy, industrial rehabilitation, and management of patients with vestibular disorders.

Jacob C. Thomas, PT, DPT, is a full-time outpatient clinician with Orthopedics Plus Physical Therapy in Bowling Green, KY. He graduated from the University of Kentucky in 2014 with a Bachelor of Science in Exercise Science and earned his Doctor of Physical Therapy (DPT) degree from the University of Kentucky in 2018. He is a member of the American Physical Therapy Association (APTA) and the American Academy of Orthopaedic Manual Physical Therapists (AAOMPT), in which he has presented research on clinical decision-making of headache disorders at the state and national levels. His areas of clinical interest include management of orthopedic pathologies, sports medicine, manual therapy, and vestibular rehabilitation.

Charles R. Hazle, PT, PhD, is an Associate Professor at the University of Kentucky, teaching in all aspects of the program relating to musculoskeletal disorders. He began teaching with UK while still a full-time clinician managing an out-patient clinic and doing on-site industrial intervention. He has authored multiple publications relating to manual therapy and co-authored two text books on musculoskeletal imaging. His particular areas of interest relate to examination efficiency, clinical reasoning, diagnostic imaging, and manual therapy. He has had multiple international involvements and taught in, presented, or treated patients in Kenya, Australia, Brazil, and Ecuador.

Appendix 1. Summary of patient case vignettes

CASE	KEY CLINICAL FINDINGS		NON-SPECIFIC/DISTRACTIVE INFORMATION
	Subjective Findings	Objective Findings
Tension-Type Headache	Frequent bilateral headaches. Dull, pressing around the head. Headache frequency: 3–4/mo. Headache duration: 8–72 h. Stressful job setting. No increase in symptoms with exercise. No relief in symptoms after onset. No imaging ordered.	No focal deficits observed with neurological exam. Slightly limited cervical active ROM grossly. Bilateral pericranial tenderness upon palpation, graded at 3/4. No loss or sx provocation with PIVMs.	Aching pain in the upper neck. Slumped sitting posture throughout the day. Previous episodes of nausea/vomiting Symptoms .aggravated by light after onset. Rest and ice at posterior neck provides mild relief. Slight forward head posture. Tenderness along the upper trapezius and suboccipital musculature. Increased tone and hypertrophy of paraspinal musculature.
Cervicogenic Headache	Dull/deep ache from posterior head to retro-orbital region (right > left). Accompanied by dizziness. Headaches related to recent increased volume at work. Headache frequency: 1–2/week. Experience of periscapular pain concurrent with neck pain. Pain increases after long hours of work. Slumped/forward head sitting posture. Mild relief of symptoms with ice at neck and acetaminophen.	Forward head posture with bilateral scapular winging. No focal deficits observed with neurological exam. Significantly limited cervical ROM grossly. Tenderness to palpation in the upper trapezius, levator scapulae, and suboccipital region. Decreased PIVMs at C5-6 & C6-7 motion segments with increase in symptoms during application.	Headaches accompanied by nausea. Symptoms exacerbated by lights. MRI reveals no structural abnormalities. Bilateral pericranial tenderness.
Migraine Headache	Onset related to moving into new apartment. Headaches occur after returning home to new apartment for 1–2 h. Headache duration: several hours – 3 days. Sharp pain that moves from left posterior head to frontal/temporal regions. Experiences frequent nausea/vomiting with headaches. Dizziness & weakness for 4–8 h. after headache. Lying down in a dark room provides significant relief.	No focal deficits observed with neurological exam. No significant cervical active ROM loss grossly. Palpation of cervical and periscapular musculature does not increase pain.	Pain in left aspect of occiput. Pain increases while sitting at computer screen with poor posture. Pain presents concurrently with neck stiffness. Pain increases to 7–8/10 after studying in new apartment. Minimal relief with naproxen sodium. MRI reveals no significant findings Forward head posture. PIVMs reveal slight motion reduction at left C2 & right C4 & C6 without pain referral.

Bolded items represent information consistent with the IHS classification criteria for the three headache disorders and which should have been identified by participants when appropriately categorizing the patient case vignettes.

Funding Statement

The authors have no sources for funding or support relative to this project.

Acknowledgments

The authors acknowledge Sydney Thompson at the UK Center of Excellence in Rural Health in Hazard, KY for assisting with the statistical analysis described. They also thank the Kentucky Physical Therapy Association and the Academy of Orthopaedic Physical Therapy for distributing the survey to their members.

Disclosure statement

No potential conflict of interest was reported by the authors.

Ethics Approval and Informed Consent

The study was approved by the Institutional Review Board (IRB) of the University of Kentucky (Protocol 17-0406-X6B).