Are headache and temporomandibular disorders related? A blinded study

To investigate overlaps between headache and temporomandibular disorders (TMD) in a clinical headache population and to describe the prevalence of TMD in headache patients, 99 patients referred to a specialized headache centre were diagnosed according to Research Diagnostic Criteria for TMD (RDC/TMD) and classified in headache groups according to the International Classification of Headache Disorders, second edition for headache diagnoses in a blinded design. The prevalence of TMD in the headache population was 56.1%. Psychosocial dysfunction caused by TMD pain was observed in 40.4%. No significant differences in TMD prevalence were revealed between headache groups, although TMD prevalence tended to be higher in patients with combined migraine and tension-type headache. Moderate to severe depression was experienced by 54.5% of patients. Patients with coexistent TMD had a significantly higher prevalence of depression-most markedly in patients with combined migraine and tension-type headache. Our studies indicate that a high proportion of headache patients have significant disability because of ongoing chronic TMD pain. The trend to a higher prevalence of TMD in patients with combined migraine and tension-type headache suggests that this could be a risk factor for TMD development. A need for screening procedures and treatment strategies concerning depression in headache patients with coexistent TMD is underlined by the overrepresentation of depression in this group. Our findings emphasize the importance of examination of the masticatory system in headache sufferers and underline the necessity of a multidimensional approach in chronic headache patients.

Increased lipid oxidation heralds diabetes onset in DR.lyp/lyp rats

AIM

The BB rat model of type 1 diabetes exhibits altered body weight gain and body temperature regulation prior to hyperglycemia onset, implying the existence of as yet unidentified biomarkers of autoimmune processes that destroy pancreatic beta cells. To investigate this hypothesis, we compared the metabolic profile of diabetes-resistant DR.lyp/+ rats and their diabetes-prone, congenic DR.lyp/lyp littermates in the days leading up to diabetes onset.

METHODS

Except for the Gimap5 mutation on chromosome 4, congenic DR.lyp/lyp rats are genetically identical to DR.lyp/+ littermates. They invariably develop hyperglycemia at 46-81 days of age, whereas DR.lyp/+ rats do not develop diabetes. In addition to daily food intake and body weight, indirect calorimetry was performed continuously on male DR.lyp/lyp and DR.lyp/+ rats (n=6/group) for 6-18 days to measure locomotor activity, VO (2), VCO (2) and RQ.

RESULTS

DR.lyp/lyp rats exhibited a progressive decrease of RQ compared to DR.lyp/+ rats 0.005+/-0.001 units/day (p<0.005). Limiting the analysis to the six days prior to diabetes onset revealed a larger decrease of 0.007+/-0.002 units/day (p<0.001) in DR.lyp/lyp animals, whereas RQ of the DR.lyp/+ rats remained unchanged. This metabolic change occurred prior to hyperglycemia onset and was not associated with changes of any other parameter.

CONCLUSIONS

Diabetes onset in DR.lyp/lyp rats is heralded by a progressive shift towards lipid oxidation relative to carbohydrate metabolism.

Glucose-stimulated increment in oxygen consumption rate as a standardized test of human islet quality

Standardized assessment of islet quality is imperative for clinical islet transplantation. We have previously shown that the increment in oxygen consumption rate stimulated by glucose (DeltaOCR(glc)) can predict in vivo efficacy of islet transplantation in mice. To further evaluate the approach, we studied three factors: islet specificity, islet composition and agreement between results obtained by different groups. Equivalent perifusion systems were set up at the City of Hope and the University of Washington and the values of DeltaOCR(glc) obtained at both institutions were compared. Islet specificity was determined by comparing DeltaOCR(glc) in islet and nonislet tissue. The DeltaOCR(glc) ranged from 0.01 to 0.19 nmol/min/100 islets (n = 14), a wide range in islet quality, but the values obtained by the two centers were similar. The contribution from nonislet impurities was negligible (DeltaOCR(glc) was 0.12 nmol/min/100 islets vs. 0.007 nmol/min/100 nonislet clusters). The DeltaOCR(glc) was statistically independent of percent beta cells, demonstrating that DeltaOCR(glc) is governed more by islet quality than by islet composition. The DeltaOCR(glc), but not the absolute level of OCR, was predictive of reversal of hyperglycemia in diabetic mice. These demonstrations lay the foundation for testing DeltaOCR(glc) as a measurement of islet quality for human islet transplantation.

Increased pain sensitivity is not a risk factor but a consequence of frequent headache: a population-based follow-up study

Altered pain sensitivity is believed to play an important role for chronification of headache. It has however mainly been evaluated in highly selected patients from headache clinics and never in longitudinal studies. The present study is a 12-year follow-up of a population-based study of primary headache disorders and pain perception, combining a diagnostic headache interview with examination of muscle tenderness and measurement of pressure pain thresholds in 1000 subjects drawn randomly from the general population in Denmark. The aim of the study was to explore the cause-effect relationship between the increased pain sensitivity and the development of headache. The pressure pain thresholds were normal at baseline but had decreased at follow-up in subjects who developed chronic tension-type headache over the 12-year period (p = 0.025). In subjects who developed frequent episodic tension-type headache the tenderness was normal at baseline but had increased at follow-up (p < 0.01) while the pain thresholds were normal both at baseline and at follow-up. The findings demonstrate that increased pain sensitivity is a consequence of frequent tension-type headache, not a risk factor, and support that central sensitization plays an important role for the chronification of tension-type headache.

Islet cell autoantibody levels after the diagnosis of young adult diabetic patients

AIMS

The aim was to determine the course of islet cell antibodies [glutamate decarboxylase (GADA), tyrosine phosphatase-like islet antigen 2 (IA-2A) and islet cell (ICA)] after the diagnosis of the diabetic patient.

METHODS

The Diabetes Incidence Study in Sweden (DISS) attempted to prospectively enrol all newly diagnosed diabetic patients aged 15-34 years during 1992 and 1993. C-peptide and autoantibody levels were determined from venous blood samples at diagnosis and again at yearly intervals for 6 years.

RESULTS

After the first year, the odds of remaining GADA positive decreased by 9% per year [odds ratio (OR) = 0.91, 95% confidence interval (CI) = 0.85-0.96] while the mean GADA index remained unchanged ( = 0.8, P = 0.37). There was no change in the percentage of subjects testing IA-2A positive after the first year ( = 0.1, P = 0.75). However, the mean index decreased 0.04 per year (95% CI: 0.03-0.05)-a 7.9% decline (95% CI: 5.4-10.4%). The odds of a subject testing positive for ICA decreased by 24% per year (OR = 0.76, 95% CI = 0.70-0.82). The mean ICA levels decreased 0.75 per year (95% CI: 0.66-0.84)-a 16.4% decline (95% CI: 14.1-18.6%). The rate of change in titres for all three autoantibodies was independent of gender, human leucocyte antigen genotype and C-peptide status.

CONCLUSIONS

GADA levels remained high while ICA levels declined. In contrast to a previous study, we found that the proportion of IA-2A subjects remaining positive did not decrease after the first year, while the average index decreased slightly.

The burden of headache in a patient population from a specialized headache centre

The aim was to characterize the individual and socio-economic impact of headache in a patient population from The Danish Headache Centre. This was a cross-sectional study using a structured interview, prospective headache diaries and standardized self-administered questionnaires using the ICHD-II criteria. Fifty-five subjects (12 male and 43 female) with a median age of 41 years and a median headache frequency of 15 days/month participated. Very high utilization of the healthcare system and a high absence rate due to headache of 12 days/year were reported. Eighty-one percent experienced a marked decrease in work effectiveness. Overall, 91% felt hampered by their headache on a daily basis and 98% had had expenses for headache medication. Frequent headache disorders are highly costly, especially due to indirect costs. Prevention, early intervention or effective treatment strategies for headache disorders may therefore be highly cost effective, not only for the individual but also for society.

The global burden of headache: a documentation of headache prevalence and disability worldwide

This study, which is a part of the initiative 'Lifting The Burden: The Global Campaign to Reduce the Burden of Headache Worldwide', assesses and presents all existing evidence of the world prevalence and burden of headache disorders. Population-based studies applying International Headache Society criteria for migraine and tension-type headache, and also studies on headache in general and 'chronic daily headache', have been included. Globally, the percentages of the adult population with an active headache disorder are 46% for headache in general, 11% for migraine, 42% for tension-type headache and 3% for chronic daily headache. Our calculations indicate that the disability attributable to tension-type headache is larger worldwide than that due to migraine. On the World Health Organization's ranking of causes of disability, this would bring headache disorders into the 10 most disabling conditions for the two genders, and into the five most disabling for women.

Combination of low-dose mirtazapine and ibuprofen for prophylaxis of chronic tension-type headache

Chronic headaches are difficult to treat and represent the biggest challenge in headache centres. Mirtazapine has a prophylactic and ibuprofen an acute effect in tension-type headache. Combination therapy may increase efficacy and lower side effects. We aimed to evaluate the prophylactic effect of a combination of low-dose mirtazapine and ibuprofen in chronic tension-type headache. Ninety-three patients were included in the double-blind, placebo-controlled, parallel trial. Following a 4-week run-in period they were randomized to four groups for treatment with a combination of mirtazapine 4.5 mg and ibuprofen 400 mg, placebo, mirtazapine 4.5 mg or ibuprofen 400 mg daily for 8 weeks. Eighty-four patients completed the study. The primary efficacy parameter, change in area under the headache curve from run-in to the last 4 weeks of treatment, did not differ between combination therapy (190) and placebo (219), P = 0.85. Explanatory analyses revealed worsening of headache already in the third week of treatment with ibuprofen alone. In conclusion, the combination of low-dose mirtazapine and ibuprofen is not effective for the treatment of chronic tension-type headache. Moreover, the study suggests that daily intake of ibuprofen worsens headache already after few weeks in chronic tension-type headache.

Discontinuation of medication overuse in headache patients: recovery of therapeutic responsiveness

It is generally accepted that ongoing medication overuse nullifies the effect of prophylactic treatment, although few data support this contention. We set out to describe the treatment outcome in patients withdrawn from medication overuse and relate any improvement to a renewed effect of prophylaxis. For patients with probable medication-overuse headache (pMOH), treated and dismissed from the Danish Headache Centre in 2002 and 2003, we assed, from prospective headache diaries, the headache frequency before and after withdrawal of offending drugs and compared these frequencies with the headache frequency at dismissal. Among 1326 patients, 337 had pMOH. Eligible were 175, mean age 49 years, male/female ratio 1 : 2.7. Overall, there was a 46% decrease in headache frequency from the first visit to dismissal (P < 0.0001). Patients with no improvement 2 months after complete drug withdrawal (N = 88) subsequently responded to pharmacological and/or non-pharmacological prophylaxis with a 26% decrease in headache frequency as measured from the end of withdrawal to dismissal (P < 0.0001). At dismissal, 47% were on prophylaxis. Former non-responders to medical prophylaxis had a 49% decrease in headache frequency from first visit to dismissal (P < 0.0001), whereas those who had never received prophylaxis had a 56% reduction (P < 0.0001). This difference was not statistically significant (P = 0.22). Almost all MOH patients benefit from drug withdrawal, either just from the withdrawal or by transformation from therapeutic non-responsiveness to responsiveness. According to the International Classification of Headache Disorders, 2nd edn, the MOH diagnosis requires improvement after drug withdrawal. Our data suggest that these diagnostic criteria are too strict.

Generalized hyperalgesia in patients with chronic tension-type headache

Increased pain sensitivity in the central nervous system may play an important role in the pathophysiology of chronic tension-type headache (CTTH). Previous studies using pain thresholds as a measure of central pain sensitivity have yielded inconsistent results and only a few studies have examined perception of muscle pain without involvement of adjacent tissues. It has been suggested that suprathreshold testing might be more sensitive than threshold measurements in evaluation of central hyperexcitability in CTTH. The aim of the study was to compare pain ratings to suprathreshold single and repetitive (2 Hz) electrical stimulation of muscle and skin in cephalic (temporal and trapezius) and extracephalic (anterior tibial) regions between patients with CTTH and healthy subjects. In addition, we aimed to examine gender differences in pain ratings to suprathreshold stimulation and degree of temporal summation of pain between patients and controls. Pain ratings to both single and repetitive suprathreshold stimulation were higher in patients than in controls in both skin and muscle in all examined cephalic and extracephalic regions (P < 0.04). Pain ratings to both single and repetitive suprathreshold electrical stimulation were significantly higher in female compared with male patients (P < 0.001) and in female compared with male controls (P < or = 0.001). The degree of temporal summation of muscular and cutaneous pain tended to be higher in patients than in controls but the differences were not statistically different. This study provides evidence for generalized increased pain sensitivity in CTTH and strongly suggests that pain processing in the central nervous system is abnormal in this disorder. Furthermore, it indicates that suprathreshold stimulation is more sensitive than recording of pain thresholds for evaluation of generalized pain perception.

Diaries and calendars for migraine. A review

Headache is one of the most common types of pain and, in the absence of biological markers, headache diagnosis depends only on information obtained from clinical interviews and physical and neurological examinations. Headache diaries make it possible to record prospectively the characteristics of every attack and the use of headache calendars is indicated for evaluating the time pattern of headache, identifying aggravating factors and evaluating the efficacy of preventive treatment. This may reduce the recall bias and increase accuracy in the description. The use of diagnostic headache diaries does have some limitations because the patient's general acceptance is still limited and some subjects are not able to fill in a diary. In this review, we considered diaries and calendars especially designed for migraine and, in particular, we aimed at: (i) determining what instruments are available in clinical practice for diagnosis and follow-up of treatments; and (ii) describing the tools that have been developed for research and their main applications in the headache field. In addition to the literature review, we added two paragraphs concerning the authors' experience of the use of diaries and calendars in headache centres and their proposals for future areas of research.

Botulinum toxin type A in the prophylactic treatment of chronic tension-type headache: a multicentre, double-blind, randomized, placebo-controlled, parallel-group study

We studied the safety and efficacy of 0 U, 50 U, 100 U, 150 U (five sites), 86 Usub and 100 Usub (three sites) botulinum toxin type A (BoNTA; BOTOX); Allergan, Inc., Irvine, CA, USA) for the prophylaxis of chronic tension-type headache (CTTH). Three hundred patients (62.3% female; mean age 42.6 years) enrolled. For the primary endpoint, the mean change from baseline in the number of TTH-free days per month, there was no statistically significant difference between placebo and four BoNTA groups, but a significant difference favouring placebo vs. BoNTA 150 was observed (4.5 vs. 2.8 tension headache-free days/month; P = 0.007). All treatment groups improved at day 60. Although efficacy was not demonstrated for the primary endpoint, at day 90, more patients in three BoNTA groups had >or=50% decrease in tension headache days than did placebo (P <or= 0.024). Most treatment-related adverse events were mild or moderate, and transient. BoNTA was safe and well-tolerated in the study.

Frequency of headache is related to sensitization: A population study

Central sensitization is thought to play an important role in the chronification of tension-type headache and in the maintenance and exacerbation of the migraine attack. It has, however, almost exclusively been studied in highly selected patients from headache clinics. The aim of the present study was to evaluate pain perception in primary headaches in the general population. Stimulus-response functions for pressure versus pain, tenderness and pressure pain thresholds were studied in a random sample of 523 adults from the general population. All results were controlled for the effects of age and gender. The area under the stimulus-response function was increased in chronic- and frequent episodic tension-type headache compared with subjects without headache (p<0.001, p<0.001) and in chronic tension-type headache compared with migraine (p=0.01). Increasing slope (p<0.0001) and displacement towards lower pressures was found in the following order: no headache, migraine, frequent episodic tension-type headache, chronic tension-type headache. The displacement of the stimulus-response function was closely associated with frequency of headache. Finally, the stimulus-response function tended to be qualitatively altered in patients with frequent headache. The findings demonstrate, for the first time in a population-based study, a close relation between altered pain perception and chronification of headache, which most likely can be explained by central sensitization.

Is there a long-lasting effect of pelvic floor muscle training in women with urinary incontinence after ischemic stroke? A 6-month follow-up study

The aim of this study was to evaluate the long-lasting effect of pelvic floor muscle training (PFMT) in women with urinary incontinence after stroke measured by quality of life parameters. Twenty-four (24/24) women with urinary incontinence after stroke, who had completed a prospective, randomised controlled and single-blinded trial evaluating the effect of 12 weeks PFMT, were included in this follow-up study. The follow-up assessments were done by telephone interview 6 months after the intervention. The effect was evaluated by The Short Form 36 (SF-36) Health Survey Questionnaire and Incontinence Impact Questionnaire (IIQ). Twenty-four subjects completed the study. In the treatment group, the SF-36 showed a trend to a long-lasting effect in one of the eight domains and the IIQ showed a tendency to decreased impact of UI in two sub-scales compared to the control group. Our data indicated that PFMT may have a long-lasting effect measured by quality of life parameters.