Migraine and tension-type headaches are highly prevalent and have a strong impact on society [
Influencing the level of LoC of patients with headache leads to faster and more sustained recovery from headaches [
The Headache-Specific Locus of Control Scale (HSLC) by Martin en Holroyd [
To assess LoC in Dutch patients with headache, the Pain Coping and Cognition List (PCCL) is used. However, the PCCL includes two domains measuring more global internal and external pain management and was not specifically developed for patients with headache. Headache-specific instruments can be useful to screen patients on their Internal or External LoC before the treatment as it may affect the outcome [
After obtaining permission from the developer (Professor Kenneth Holroyd, Ohio University), the original HSLC questionnaire was translated by a translation agency. Two translators independently translated the original US English version of the HSLC into Dutch. A third independent translator merged these two Dutch HSLC versions into the best suitable Dutch translation for each item. Subsequently, this Dutch version of the HSLC was backward translated into English by two other independent translators of the translation agency. These independent translators were unacquainted with the original US English version of the HSLC. Another independent translator translated again forward into Dutch.
A focus group consisting of four content experts with regard to the target group achieved consensus on comprehensibility and translation. Subsequently, 20 health-care professionals (10 psychologists and 10 general practitioners) evaluated the equivalence between the original and the translated version of the HSLC. After this assessment, the final Dutch version was composed, the HSLC-DV (
Eligible participants were patients with a history of headaches visiting two referral centers (“Corpus Mentis, Center for Physical Therapy & Science” or “het Wantveld”) for treatment. Additionally, patients were recruited through the websites of the Dutch Association for Physical Therapy & Science (part of Corpus Mentis) and two patient support groups of the Dutch Migraine Association. The participants of the support groups were already diagnosed with migraine by visiting a physician in the past. Migraine patients were not recruited in the referral centers because they are not visiting a physiotherapist for their headache problems on a regular basis. Patients with migraine [
The participants included from Wantveld and Corpus Mentis were diagnosed by the physical therapist through history taking and physical examination, and after inclusion they filled out the survey. Patients completed the survey after inclusion (T0) and after three weeks (T1). The survey included the HSLC-DV (
The HSLC [
The PCCL [
The NPRS [
A Global Rating of Change (GRC) was included at T1 to inquire to what extent the headache complaints were changed at follow-up. A score of −5 indicates much worsened symptoms compared to the previous measurement, 0 indicates unchanged, and +5 indicates a maximum improvement compared to the previous measurement.
Patients were recruited from May 2014 to February 2015. Questions on demographic and clinical characteristics were included in the T0 survey. Patients provided self-reported information including headache intensity, headache episodes and headache duration, age and gender as well as work status, children, doctors’ visits, sport, education level, civil status, and medication use (Table
Baseline characteristics.
Total sample ( |
Lost to follow-up ( |
|
---|---|---|
Gender | ||
Male | 21 (24%) | 3 (19%) |
Mean (SD) age in years | 36 (9) | 35 (7) |
Headache type | ||
Migraine | 35 (40%) | 5 (31%) |
Tension type and cervicogenic headache | 52 (60%) | 11 (69%) |
Median (range) headache days per month | 8 (1–31) | 8 (4–30) |
Median duration of headache in years | 13 (1–45) | 13 (3–30) |
Median duration of headache period in days | 3 (0.5–31) | 2 (0.5–6) |
Headache treatment | 34 (39%) | 4 (25%) |
Work | ||
Full-time | 40 (46%) | 7 (44%) |
Part-time | 32 (37%) | 7 (44%) |
No paid work | 11 (13%) | 1 (6%) |
Freelance | 4 (4%) | 1 (6%) |
Median (range) number of children | 0 (0–6) | 1 (0–3) |
Sports or moderate physical activity for 30 min a day1 | ||
No sports or moderate physical activity | 26 (30%) | 9 (56%) |
Moderate physical activity only | 32 (37%) | 4 (25%) |
>2x a week sport | 29 (33%) | 3 (19%) |
Education2 | ||
Low | 44 (51%) | 8 (50%) |
High | 43 (49%) | 8 (50%) |
Civil status | ||
Single | 18 (21%) | 2 (13%) |
Relation, living with partner, (re)married | 65 (75%) | 13 (81%) |
Divorced | 4 (5%) | 1 (6%) |
Medication | ||
Pain medication | 63 (72%) | 13 (81%) |
Beta-blocker | 2 (2%) | 0 (0%) |
Blood pressure-lowering drugs | 3 (3%) | 0 (0%) |
Doctors visit in median times a year | 2 (0–25) | 2 (0–6) |
HSLC | ||
External | 24.2 (6.9) | 23.4 (5.2) |
Internal | 34.9 (9.3) | 37.8 (9.5) |
Chance | 33.8 (7.0) | 35.0 (5.3) |
Numbers are frequencies (%), mean (SD), or median (range). 1Dutch norm for healthy exercise. 2High education = higher vocational education and science education.
The survey was provided on paper and as an online version. Participants who did not respond to the request to fill out the questionnaires received a reminder by e-mail after 10 days. After two reminders, patients were excluded from the analysis.
Reproducibility of the HSLC-DV domain scores was assessed by comparing the scores on T0 and T1 using intraclass correlations (ICCs), (consistency model, single measures). The reproducibility of the item scores was investigated using weighted kappas. Weighted kappas were estimated by calculating ICCs [
Validity of the Dutch HSLC was evaluated by the correlations of HSLC-DV domains with corresponding domains of the PCCL. We regarded correlations between 0.1 and 0.3 as low, between 0.3 and 0.5 as medium, and between 0.5 and 0.7 as high [ We expected lower Internal LoC scores for the Tension-Type and Cervicogenic Headache group compared to the Migraine-Type group. Tension-type headache and cervicogenic headache are more often the results of stress and burnout complaints that are in turn associated with lower Internal LoC scores [ We expected higher Internal scores for higher educated people compared to lower educated people. According to Pellino and Oberst, a higher educational level may indicate that the individual has more problem-solving ability or a higher level of self-efficacy in dealing with chronic pain [ We expected higher Internal LoC scores for men compared to woman. Men were found to be more inclined to believe that headache problems and headache relief are determined by their own actions or behaviors [ We expected higher Internal LoC scores for subjects who actively practiced sports or engaged daily in at least 30 minutes of moderate physical activity compared to those who did not. The positive influence of sports activity on the production of endorphins reduces the stress hormone cortisol [ We expected higher External LoC scores for subjects under (medical) headache treatment compared to no-headache treatment. Higher levels of medication use and preference for medical treatment were associated with External LoC in the original US study and the Spanish validation [ We expected higher Chance LoC scores with more frequent headache days per month [ We expected higher Chance LoC scores with longer duration in days of headache episodes [
Structural validity of the HSLC-DV was examined by a principal axis factoring analysis with orthogonal (Varimax) rotation in order to test the purported subscale structure of the HSLC-DV. A forced three-factor structure was used. Factor loadings > 0.40 for individual items were considered indicative of subscale domain membership. Kaiser–Meyer–Olkin test was used to examine whether the data are suited for factor analysis. KMO test values may range between 0 and 1. Values below 0.50 are deemed unacceptable. KMO measure of sampling adequacy was 0.69 indicating that the sample was large enough to conduct a principal component analysis.
Numerical data were presented as mean (SD) or median (range) as appropriate. Differences between clinical subgroups were assessed with independent
There were no missing values on individual HSLC-DV items on T0. For the respondents on T1, one patient had 3 missing items, two had two missing items, and seven patients had one missing item. Little’s MCAR test was not significant, and missing item values were imputed by expectation-maximization.
A total of 87 patients with headache completed the survey at T0, and 16 patients did not return or completed the survey after three weeks at T1 (Figure
Flowchart.
The reproducibility and internal consistency results are summarized in Table
Reproducibility and internal consistency of the HSLC-DV (
Weighted kappa | Item-rest correlation | Cronbach’s alpha if item deleted | Cronbach’s alpha | |
---|---|---|---|---|
External LoC | 0.79 (0.75 |
|||
HSLC6 | 0.24 | 0.12 | 0.80 | |
HSLC8 | 0.43 | 0.47 | 0.77 | |
HSLC10 | 0.44 | 0.56 | 0.76 | |
HSLC12 | 0.34 | 0.28 | 0.79 | |
HSLC14 | 0.61 | 0.54 | 0.76 | |
HSLC15 | 0.34 | 0.26 | 0.79 | |
HSLC16 | 0.69 | 0.55 | 0.76 | |
HSLC22 | 0.69 | 0.51 | 0.76 | |
HSLC24 | 0.77 | 0.47 | 0.77 | |
HSLC27 | 0.58 | 0.44 | 0.77 | |
HSLC30 | 0.62 | 0.61 | 0.75 | |
|
||||
Internal LoC | 0.89 (0.88 |
|||
HSLC2 | 0.57 | 0.60 | 0.88 | |
HSLC4 | 0.21 | 0.56 | 0.88 | |
HSLC5 | 0.60 | 0.66 | 0.88 | |
HSLC7 | 0.59 | 0.52 | 0.89 | |
HSLC11 | 0.59 | 0.67 | 0.88 | |
HSLC17 | 0.68 | 0.79 | 0.87 | |
HSLC19 | 0.62 | 0.73 | 0.87 | |
HSLC21 | 0.53 | 0.61 | 0.88 | |
HSLC26 | 0.44 | 0.38 | 0.89 | |
HSLC28 | 0.70 | 0.67 | 0.88 | |
HSLC32 | 0.55 | 0.57 | 0.88 | |
|
||||
Chance LoC | 0.73 (0.71 |
|||
HSLC1 | 0.60 | 0.49 | 0.70 | |
HSLC3 | 0.66 | 0.60 | 0.68 | |
HSLC9 | 0.63 | 0.43 | 0.71 | |
HSLC13 | 0.57 | 0.56 | 0.69 | |
HSLC18 | 0.58 | −0.02 | 0.77 | |
HSLC20 | 0.43 | 0.32 | 0.72 | |
HSLC23 | 0.60 | 0.53 | 0.70 | |
HSLC25 | 0.61 | 0.55 | 0.69 | |
HSLC29 | 0.68 | 0.06 | 0.76 | |
HSLC31 | 0.51 | 0.39 | 0.71 | |
HSLC33 | 0.56 | 0.36 | 0.72 |
LoC = Locus of Control subscale. Numbers correspond to the original HSLC scale.
The intraclass correlations (95%CI) for the External, Internal, and Chance domains were 0.77 (0.65–0.85), 0.81 (0.70–0.88), and 0.79 (0.67–0.86), respectively.
The mean difference between the External scores on the HSLC-DV between T0 and T1 was −0.42 points, and limits of agreement (LoA) were −11.2 to 10.4 points. The mean differences (LoA) for the Internal scores and the Chance scores were −0.94 (−12.1–10.2) and 0.85 (−8.7–10.4), respectively. For a subsample of the participants with GRC scores −1 to +1 (
Table
Pearson correlations between HSLC subscales and similar domains of the PCCL (
PCCL external | PCCL internal | PCCL catastrophizing | |
---|---|---|---|
HSLC external |
|
0.12 | 0.20 |
HSLC internal | −0.10 |
|
−0.02 |
HSLC chance | 0.27 |
−0.35 |
|
Convergent correlations are given in bold. HSLC = Headache-Specific Locus of Control Scale; PCCL = Pain Coping and Cognition List.
Table
Known groups and hypotheses (
External | Internal | Chance | ||
---|---|---|---|---|
(1) | Migraine ( |
24.98 (7.20) | 32.88 (9.78) | 33.68 (6.68) |
Tension type + cervicogenic headache ( |
23.61 (6.65) | 36.24 (8.87) | 33.93 (7.25) | |
|
|
| ||
|
||||
(2) | Education, low ( |
25.47 (6.87) | 34.65 (9.52) | 34.36 (6.90) |
Education, high ( |
22.82 (6.67) | 35.13 (9.26) | 33.29 (7.12) | |
|
|
| ||
|
||||
(3) | Male ( |
23.97 (6.27) | 37.70 (7.04) | 32.34 (8.05) |
Female ( |
24.22 (7.09) | 33.99 (9.84) | 34.30 (6.61) | |
|
|
| ||
|
||||
(4) | No sport ( |
23.30 (5.65) | 38.71 (9.74) | 32.68 (5.92) |
Moderate activity + 2x wk sports ( |
24.53 (7.34) | 33.26 (8.75) | 34.32 (7.39) | |
0.47 |
|
| ||
|
||||
(5) | No treatment ( |
22.99 (6.15) | 35.39 (9.97) | 33.54 (6.44) |
Treatment ( |
25.99 (7.59) | 34.11 (8.36) | 34.27 (7.85) | |
|
|
| ||
|
||||
(6) | 0–8 headache days per month ( |
23.73 (6.01) | 35.76 (8.34) | 31.22 (6.35) |
9–31 headache days per month ( |
24.60 (7.69) | 34.00 (10.29) | 36.50 (6.65) | |
|
|
| ||
|
||||
(7) | 0–3 days per headache period ( |
24.14 (6.1) | 34.84 (8.89) | 32.54 (6.46) |
4–31 days per headache period ( |
24.20 (8.30) | 36.75 (9.05) | 36.40 (7.40) | |
|
|
|
The factor analysis (Table
Structural validity: factor loadings on the purported subscales of the HSLC-DV scale.
Internal LoC eigenvalue = 6.8 | External LoC eigenvalue = 4.3 | Chance LoC eigenvalue = 2.4 | ||
---|---|---|---|---|
External LoC | HSLC6 |
0.168 |
|
0.228 |
HSLC8 | 0.190 |
|
0.229 | |
HSLC10 | 0.230 |
|
−0.080 | |
HSLC12 | 0.056 |
|
0.118 | |
HSLC14 | −0.108 |
|
0.153 | |
HSLC15 |
−0.093 |
|
0.145 | |
HSLC16 | −0.112 |
|
0.028 | |
HSLC22 | 0.220 |
|
−0.134 | |
HSLC24 | −0.052 |
|
0.188 | |
HSLC27 | 0.030 |
|
0.037 | |
HSLC30 | 0.062 |
|
0.057 | |
|
||||
Internal LoC | HSLC2 |
|
−0.013 | −0.123 |
HSLC4 |
|
0.037 | −0.157 | |
HSLC5 |
|
0.000 | −0.195 | |
HSLC7 |
|
0.147 | 0.023 | |
HSLC11 |
|
−0.012 | −0.076 | |
HSLC17 |
|
0.061 | −0.216 | |
HSLC19 |
|
0.054 | 0.037 | |
HSLC21 |
|
0.084 | −0.353 | |
HSLC26 |
|
−0.067 | −0.281 | |
HSLC28 |
|
−0.041 | −0.083 | |
HSLC32 |
|
0.019 | −0.201 | |
|
||||
Chance LoC | HSLC1 | −0.224 | −0.148 |
|
HSLC3 | −0.205 | −0.217 |
|
|
HSLC9 | −0.249 | 0.019 |
|
|
HSLC13 | −0.142 | 0.122 |
|
|
HSLC18 |
0.479 | 0.114 |
|
|
HSLC20 | 0.041 | 0.162 |
|
|
HSLC23 | −0.020 | 0.186 |
|
|
HSLC25 | −0.129 | 0.271 |
|
|
HSLC29 |
−0.032 | −0.223 |
|
|
HSLC31 | −0.130 | 0.163 |
|
|
HSLC33 | −0.276 | −0.181 |
|
Three factors explained 41% of the total variance in HSLC-DV scores.
We translated and validated the HSLC in a Dutch sample. The item reproducibility over a similar time interval as the original US study was generally good, except for item 4 (prevent headaches by not getting emotionally upset) and item 6 (prevent headaches by doctor). We found a comparable internal consistency as reported in the US and Danish validation studies. Most items contributed to the internal consistency although some items (items 6, 18, and 29) did not. The convergent correlations (>0.40) and divergent correlations (<0.30) between subscales of the HSLC-DV and related subscales of the PCCL were as expected. Only the HSLC Chance subscale correlated somewhat lower with the PCCL Catastrophizing scale (0.36). Catastrophizing in the US study was considered as a strategy for coping with headaches when chance or fate play a primary role in the onset of headache episodes. This is similar to what is measured by the HSLC Chance scale. Structural validity of the HSLC-DV was supported by the principal component analysis results. The vast majority of the items exclusively loaded on the intended subscales.
We expected a difference between men and woman. Men were found to be more inclined to believe that headache problems and headache relief are determined by their own actions or behaviors. This difference was not found in our results, comparable with Cano-García et al. [
From the seven HSLC known groups hypotheses, five were confirmed of which two reached no statistical significance. For example, contrary to what was expected, the mean Internal LoC score in the Tension-Type and Cervicogenic Headache group was higher than that in the Migraine-type group. We argue that the HSLC measures symptoms that may be present in all the three types of headaches. Hence, the hypotheses outcomes were not as expected for the different types.
Migraine patients are usually comorbid to depression [
No difference was observed for “sports or moderate physical activity for 30 min a day” with lower Internal LoC scores for physically active subjects.
In our study, the relatively small sample size for the Principal Component Analysis is the first limitation. Further research in larger sample sizes should be completed to reach more definite conclusions regarding the structural validity of the HSLC-DV. A second limitation of this study is possible selection bias. A part of the sample may not be representative of the regular headache subjects visiting the referral centers for treatment because we also recruited patients from patient-support groups. This could have led to inclusion of patients with chronic headache with longer disease duration. We argue that patients with longer sustained headaches were more willing to participate in this study, as we can see in the high median duration of headaches in years at baseline of this group. In our study, more women (75%) were included than men. We argue that this could be a representative reflection of the headache population because women are affected 2 to 4 times more often by headaches than men [
Finally, Nilsson and Bove have classified TTH and CH together as “musculoskeletal headache” [
We conclude that the HSLC-DV is a reliable and valid instrument to measure LoC in a Dutch sample of patients with headache. Therefore, we strongly recommend the use of the HSLC-DV in the treatment counseling of patients with headache. Future research is necessary to determine cutoff points for the different scales of the HSLC-DV to identify patients with poor outcome on the headache treatment.
1 = Volkomen oneens 2 = Gematigd oneens 3 = Neutraal 4 = Gematigd eens 5 = Volkomen eens Hoofdpijn-Specifiek Locus of Control (HSLC-DV) scale1. Als ik hoofdpijn heb is er niets wat ik kan doen om het beloop te veranderen 1 2 3 4 5 2. Ik ben in staat een deel van mijn hoofdpijn te voorkomen door het vermijden van bepaalde stressvolle situaties 1 2 3 4 5 3. Ik ben compleet machteloos met betrekking tot mijn hoofdpijn 1 2 3 4 5 4. Ik kan hoofdpijn soms voorkomen door niet overstuur te raken 1 2 3 4 5 5. Wanneer ik zorg voor voldoende rust heb ik minder vaak hoofdpijn 1 2 3 4 5 6. Alleen mijn arts kan mij aanwijzingen geven om mijn hoofdpijn te voorkomen 1 2 3 4 5 7. Mijn hoofdpijn is soms erger omdat ik overactief ben 1 2 3 4 5 8. Mijn hoofdpijn kan minder erg zijn wanneer medische professionals mij goede zorg verlenen. (Artsen, zusters, etc.) 1 2 3 4 5 9. Ik heb geen enkele invloed op mijn hoofdpijn 1 2 3 4 5 10. De behandeling van mijn arts kan mij helpen tegen hoofdpijn 1 2 3 4 5 11. Wanneer ik mij zorgen maak of pieker over iets heb ik een grotere kans op hoofdpijn 1 2 3 4 5 12. Alleen al een bezoek aan mijn arts helpt tegen mijn hoofdpijn 1 2 3 4 5 13. Ongeacht wat ik doe: als ik hoofdpijn zal krijgen, dan krijg ik het ook 1 2 3 4 5 14. Regelmatig contact met mijn arts is de beste manier voor mij om controle te krijgen over mijn hoofdpijn 1 2 3 4 5 15. Wanneer ik hoofdpijn heb dien ik een medische deskundige te raadplegen 1 2 3 4 5 16. Het zorgvuldig volgen van de door mijn arts uitgeschreven medicijnenkuur is de beste manier om hoofdpijn te voorkomen 1 2 3 4 5 17. Wanneer ik teveel van mijzelf vraag krijg ik hoofdpijn 1 2 3 4 5 18. Geluk speelt een grote rol bij het bepalen hoe snel ik zal herstellen van hoofdpijn 1 2 3 4 5 19. Door er voor te zorgen dat ik niet overactief of geïrriteerd raak voorkom ik veel hoofdpijn 1 2 3 4 5 20. Het niet krijgen van hoofdpijn is voornamelijk een kwestie van geluk 1 2 3 4 5 21. De dingen die ik doe beïnvloeden de kans op hoofdpijn 1 2 3 4 5 22. Gewoonlijk herstel ik van een hoofdpijn na het ontvangen van goede medische zorg 1 2 3 4 5 23. Ik heb een grote kans op hoofdpijn, ongeacht wat ik doe 1 2 3 4 5 24. Wanneer ik niet de juiste medicatie heb, heb ik last van hoofdpijn 1 2 3 4 5 25. Vaak heb ik het gevoel dat wat ik ook doe ik toch hoofdpijn zal krijgen 1 2 3 4 5 26. Ik ben zelf verantwoordelijk voor het krijgen van hoofdpijn 1 2 3 4 5 27. Wanneer mijn arts een vergissing maakt, ben ik degene die daaronder lijdt door hoofdpijn 1 2 3 4 5 28. Mijn hoofdpijn wordt erger wanneer ik met stress te maken heb 1 2 3 4 5 29. Wanneer ik hoofdpijn krijg moet ik de natuur gewoon zijn gang laten gaan 1 2 3 4 5 30. Professionele medische deskundigen zorgen dat ik geen hoofdpijn krijg 1 2 3 4 5 31. Ik heb simpelweg geluk wanneer ik een maand geen hoofdpijn heb 1 2 3 4 5 32. Wanneer ik niet goed voor mezelf zorg heb ik een grote kans op hoofdpijn 1 2 3 4 5 33. Het is een kwestie van toeval of ik hoofdpijn krijg 1 2 3 4 5
Explanation domains: External subscale: 6, 8, 10, 12, 14, 15, 16, 22, 24, 27, 30. Internal subscale: 2, 4, 5, 7, 11, 17, 19, 21, 26, 28, 32. Chance subscale: 1, 3, 9, 13, 18, 20, 23, 25, 29, 31, 33.
The authors declare that there are no conflicts of interest regarding the publication of this article.
The authors want to thank Kenneth Holroyd for providing copies of the original versions of HSLC and useful advice on the process to accomplish this study. Additionally, the authors want to express their gratitude to the Dutch Association for Physical Therapy & Science for providing an online survey and all the support in recruiting the patients for this study. Furthermore, the authors thank the focus group for assessing equivalence between the original and the translated version of the HSLC. The authors thank the psychologists from Primary Care Psychology (PEP) “Wantveld” and general practitioners from Health Center “Wantveld” for assistance in recruiting patients with headache symptoms.