Exteroceptive silent period of temporalis muscle in menstrual headaches
Jean Schoenen, Dominique Bottin, José Sulon, Ulysse Gaspard, René Lambotte
Cephalalgia Schoenen J, Bottin D, Sulon J, Gaspard U, Lambotte R. Exteroceptive silent period of temporalis muscle in menstrual headaches. Cephalalgia 1991;11:87-91. Oslo. ISSN 0333-1024 The second exteroceptive silent period (ES2) of temporalis muscle was recorded on days 1 and 15 of the menstrual cycle in 17 women, 9 of whom suffered regularly from tension-type headaches during menstruation. Mean duration of temporalis ES2 was significantly shorter on day I of the cycle than on day 15. This difference was due to a marked menstrual reduction of ES2 in the headache subgroup. A positive correlation was found between ES2 durations and oestradiol/progesterone ratios. We hypothesize that the variations of ES2 during the ovarian cycle result from the modulatory effects of oestrogens on descending aminergic pathways that control excitability of inhibitory brainstem interneurons mediating exteroceptive suppression of jaw-closing motoneurons. • Exteroceptive silent period, menstrual headache, oestradiol, progesterone, temporalis muscle Jean Schoenen, University Department of Neurology, Headache Clinic; Dominique Bottin, José Sulon, Ulysse Gaspard, Rend Lambotte, University Department of Gynaecology and Obstetrics; all at CHR Citadelle, University of Liege, Belgium; Correspondence to lean Schoenen; Accepted 12 February 1991 The premenstrual syndrome affects approximately 40% of women, 10% of whom are severely incapacitated (1, 2). Headache is only one of the symptom s associated with premenstrual syndrome (3, 4). Severe headaches in the perimenstrual period usually have the clinical characteristics of migraine, hence the term "menstrual migraine" (5, 6). Roughly 60% of women with migraine relate the periodicity of heir headache to their menstrual cycle, while about a quarter of them have their headaches exclusively at the time of menstruation (5-8). Conversely, headaches related to menstruation may be moderate, especially so in women with other symptoms of the premenstrual syndrome. They rather fulfil the diagnostic criteria of tension-type headache (4, 9, 10). We have shown previously that the second exteroceptive silent period (ES2) recorded in temporalis muscle is shortened or abolished in chronic tension-type headache (11), a finding which was recently confirmed by another group (12). It is known that the inhibitory brainstem interneurons mediating ES2 of jaw-closing muscles (13, 14) receive a strong input from the so-called limbic pathways, some of which are aminergic and are also involved in pain control (15, 16). There is experimental evidence for inhibitory reflexes in jaw-closing muscles being modulated by central serotoninergic pathways (17) and for gonadal hormones influencing central aminergic systems (18). Bearing these clinical and experimental data in mind, it seemed of interest to study temporalis ES2 at different stages of the ovarian cycle in women reporting menstrual tension-type headaches. Patients and methods
Seventeen female volunteers were included in this study. They had regular menstrual cycles and were not taking any hormonal preparation. Their mean age was 28 years (20 to 43). Nine of them reported headaches consistently occurring in the perimenstrual period. These headaches were of moderate intensity, did not interfere with normal activities, were not accompanied by nausea or by photophobia, and thus fulfilled the diagnostic criteria of tension-type headache (19). On occasion the headache was associated with moderate symptoms of the premenstrual syndrome, such as dysphoria, fatigue, breast tension or tenderness, backache. The eight remaining women had no headaches. The exteroceptive silent period of temporalis muscle was recorded on the left side according to a previously published protocol (11). Briefly, surface EMG electrodes are placed over the anterior temporal region and, while the subject is clenching his teeth, a slightly painful electrical stimulus of at least 20 mA intensity is applied to the labial commissure. In previous studies (11) stimulation rates of 0.1, 0.5 and 2 Hz were used in order to assess habituation of the response. Since habituation was most pronounced at 2 Hz, the present study was restricted to the 0.1 and 2 Hz rates. Ten responses were averaged for each stimulation rate. Temporalis ES2 recordings were performed on the first day of menses (day 1) and at mid-cycle (day 15). On the same days, blood samples were drawn in each subject to determine by radioimmunoassay plasma levels of oestradiol and progesterone. Statistics were performed using Student's t-test
for group comparisons as well as for modifications of a variable at two different time periods, and Spearman's rank test for the correlation between two variables. Results
In tile group of 17 women taken as a whole, mean durations of ES2 tended to be shorter during menstruation than at mid-cycle for both the 0.1 Hz and 2 Hz stimulation rate (Fig. 1). These differences just reached the level of statistical significance. When two subgroups of women were considered separately, i.e. 8 women without headache on the one hand, 9 women with menstrual tension-type headache on the other, it was clear that most of the reduction in ES2 during menstruation could be ascribed to the headache group (Table 1). This table illustrates that the variations in ES2 during the menstrual cycle, both at the 0.1 and at the 2 Hz stimulation rate, are not significant in the non-headache group, while they are highly significant in the headache group. Between the two subgroups of women, differences in duration of ES2 were statistically significant only at the stimulation rate of 0.1 Hz. It must be pointed out that only 2 out of the 9 women in the headache group complained of headache at the time the electrophysiologic recordings were performed. Plasma levels of oestradiol or progesterone did not differ significantly between women with and without menstrual headaches. For instance, oestradiol levels at the first day of menses were 31.78 pg/ml ± 16.3 (SD) in the headache and 37.17 ± 4.7 in the non-headache subgroup. Corresponding values for progesterone were 1.97 ng/ ml ± 2.7 (SD) and 0.35 ± 0.18. At mid-cycle, oesTable 1. Temporalis ES2 (mean ± SEM) at 0.1 and 2 Hz in the non-headache and headache groups on days I and 15 of menstrual cycle. P values are given for inter- and intragroup comparisons (see text for comments). ES2 at 0.1 Hz ES2 at 2 Hz (ms: mean ± SEM) (ms: mean ± SEM) p values p values 1st day 15th day paired t-test 1st day 15th day paired t-test Non-headache 56.9 ± 4.4 61.9 ±3.9 NS 23.3 ± 6.3 31.4 ± 5.1 NS group (n = 8) Headache 30.1 ± 4.4 45.5 ± 4.0
Jean Schoenen, Dominique Bottin, José Sulon, Ulysse Gaspard, René Lambotte
Cephalalgia Schoenen J, Bottin D, Sulon J, Gaspard U, Lambotte R. Exteroceptive silent period of temporalis muscle in menstrual headaches. Cephalalgia 1991;11:87-91. Oslo. ISSN 0333-1024 The second exteroceptive silent period (ES2) of temporalis muscle was recorded on days 1 and 15 of the menstrual cycle in 17 women, 9 of whom suffered regularly from tension-type headaches during menstruation. Mean duration of temporalis ES2 was significantly shorter on day I of the cycle than on day 15. This difference was due to a marked menstrual reduction of ES2 in the headache subgroup. A positive correlation was found between ES2 durations and oestradiol/progesterone ratios. We hypothesize that the variations of ES2 during the ovarian cycle result from the modulatory effects of oestrogens on descending aminergic pathways that control excitability of inhibitory brainstem interneurons mediating exteroceptive suppression of jaw-closing motoneurons. • Exteroceptive silent period, menstrual headache, oestradiol, progesterone, temporalis muscle Jean Schoenen, University Department of Neurology, Headache Clinic; Dominique Bottin, José Sulon, Ulysse Gaspard, Rend Lambotte, University Department of Gynaecology and Obstetrics; all at CHR Citadelle, University of Liege, Belgium; Correspondence to lean Schoenen; Accepted 12 February 1991 The premenstrual syndrome affects approximately 40% of women, 10% of whom are severely incapacitated (1, 2). Headache is only one of the symptom s associated with premenstrual syndrome (3, 4). Severe headaches in the perimenstrual period usually have the clinical characteristics of migraine, hence the term "menstrual migraine" (5, 6). Roughly 60% of women with migraine relate the periodicity of heir headache to their menstrual cycle, while about a quarter of them have their headaches exclusively at the time of menstruation (5-8). Conversely, headaches related to menstruation may be moderate, especially so in women with other symptoms of the premenstrual syndrome. They rather fulfil the diagnostic criteria of tension-type headache (4, 9, 10). We have shown previously that the second exteroceptive silent period (ES2) recorded in temporalis muscle is shortened or abolished in chronic tension-type headache (11), a finding which was recently confirmed by another group (12). It is known that the inhibitory brainstem interneurons mediating ES2 of jaw-closing muscles (13, 14) receive a strong input from the so-called limbic pathways, some of which are aminergic and are also involved in pain control (15, 16). There is experimental evidence for inhibitory reflexes in jaw-closing muscles being modulated by central serotoninergic pathways (17) and for gonadal hormones influencing central aminergic systems (18). Bearing these clinical and experimental data in mind, it seemed of interest to study temporalis ES2 at different stages of the ovarian cycle in women reporting menstrual tension-type headaches. Patients and methods
Seventeen female volunteers were included in this study. They had regular menstrual cycles and were not taking any hormonal preparation. Their mean age was 28 years (20 to 43). Nine of them reported headaches consistently occurring in the perimenstrual period. These headaches were of moderate intensity, did not interfere with normal activities, were not accompanied by nausea or by photophobia, and thus fulfilled the diagnostic criteria of tension-type headache (19). On occasion the headache was associated with moderate symptoms of the premenstrual syndrome, such as dysphoria, fatigue, breast tension or tenderness, backache. The eight remaining women had no headaches. The exteroceptive silent period of temporalis muscle was recorded on the left side according to a previously published protocol (11). Briefly, surface EMG electrodes are placed over the anterior temporal region and, while the subject is clenching his teeth, a slightly painful electrical stimulus of at least 20 mA intensity is applied to the labial commissure. In previous studies (11) stimulation rates of 0.1, 0.5 and 2 Hz were used in order to assess habituation of the response. Since habituation was most pronounced at 2 Hz, the present study was restricted to the 0.1 and 2 Hz rates. Ten responses were averaged for each stimulation rate. Temporalis ES2 recordings were performed on the first day of menses (day 1) and at mid-cycle (day 15). On the same days, blood samples were drawn in each subject to determine by radioimmunoassay plasma levels of oestradiol and progesterone. Statistics were performed using Student's t-test
for group comparisons as well as for modifications of a variable at two different time periods, and Spearman's rank test for the correlation between two variables. Results
In tile group of 17 women taken as a whole, mean durations of ES2 tended to be shorter during menstruation than at mid-cycle for both the 0.1 Hz and 2 Hz stimulation rate (Fig. 1). These differences just reached the level of statistical significance. When two subgroups of women were considered separately, i.e. 8 women without headache on the one hand, 9 women with menstrual tension-type headache on the other, it was clear that most of the reduction in ES2 during menstruation could be ascribed to the headache group (Table 1). This table illustrates that the variations in ES2 during the menstrual cycle, both at the 0.1 and at the 2 Hz stimulation rate, are not significant in the non-headache group, while they are highly significant in the headache group. Between the two subgroups of women, differences in duration of ES2 were statistically significant only at the stimulation rate of 0.1 Hz. It must be pointed out that only 2 out of the 9 women in the headache group complained of headache at the time the electrophysiologic recordings were performed. Plasma levels of oestradiol or progesterone did not differ significantly between women with and without menstrual headaches. For instance, oestradiol levels at the first day of menses were 31.78 pg/ml ± 16.3 (SD) in the headache and 37.17 ± 4.7 in the non-headache subgroup. Corresponding values for progesterone were 1.97 ng/ ml ± 2.7 (SD) and 0.35 ± 0.18. At mid-cycle, oesTable 1. Temporalis ES2 (mean ± SEM) at 0.1 and 2 Hz in the non-headache and headache groups on days I and 15 of menstrual cycle. P values are given for inter- and intragroup comparisons (see text for comments). ES2 at 0.1 Hz ES2 at 2 Hz (ms: mean ± SEM) (ms: mean ± SEM) p values p values 1st day 15th day paired t-test 1st day 15th day paired t-test Non-headache 56.9 ± 4.4 61.9 ±3.9 NS 23.3 ± 6.3 31.4 ± 5.1 NS group (n = 8) Headache 30.1 ± 4.4 45.5 ± 4.0
