Quantitative EEG Power and Asymmetry Increase 36 h Before a Migraine Attack

The aim was to estimate ictal, pre- and postictal brain function changes in migraine in a blinded paired quantitative EEG (QEEG) study. EEG recordings ( n = 119) from 40 migraineurs were retrospectively classified as ictal, interictal, preictal or postictal. δ, θ, α and β power, and hemispheric asymmetry in frontocentral, temporal and occipitoparietal regions were calculated from artefact-free EEG. Power and power asymmetry were calculated for two time-windows, 36 and 72 h before/after the attack, and compared with the interictal values. Frontocentral δ power increased ( P = 0.03), whereas frontocentral θ and α power tended to increase ( P < 0.09) within 36 h before the next attack compared with the interictal period. Occipitoparietal (α and θ) and temporal (α) power were more asymmetric before the attack compared with the interictal baseline ( P < 0.04). Ictal posterior a power increased slightly ( P = 0.01). Postictal power and power asymmetry were not significantly different from interictal baseline. EEG activity seems to change shortly before the attack. This suggests that migraineurs are most susceptible to attack when anterior QEEG δ power and posterior α and θ asymmetry values are high. Changed activity patterns in cholinergic brainstem or basal forebrain nuclei and thalamo-cortical connections before the migraine attack are hypothesized.

A unilateral sympathetic blockade does not affect stress-related pain and muscle activity in patients with chronic musculoskeletal pain

OBJECTIVE

Chronic musculoskeletal pain is often exacerbated by mental and social stress. The association between stress and musculoskeletal pain is potentially mediated by peripheral sympathetic nerves, either directly or indirectly through muscle activity. In the present study we wanted to determine whether sympathetic blockade could affect either the pain or the muscular activity experienced during mental stress in patients with chronic musculoskeletal pain.

METHODS

We performed a unilateral anaesthetic blockade of the lower cervical sympathetic ganglion (ganglion stellatum) in 18 patients with chronic musculoskeletal pain (10 with fibromyalgia and eight with chronic shoulder/neck pain). After the blockade the patients performed a 60-minute stressful task with low-grade mental stress that has induced pain and muscle activity in earlier experiments. Surface electromyography (SEMG) of the forehead, temples, neck, and shoulders, and heart rate and blood pressure were recorded together with ratings of pain.

RESULTS

We did not find any side or sidextime effect for pain or muscular activity in any of the four muscle groups (p>0.12).

CONCLUSION

We investigated the potential involvement of peripheral sympathetic nerves in stress-related musculoskeletal pain. A peripheral sympathetic block did not affect pain and muscle responses to a stressful task. Other explanatory models should be implemented and tested experimentally to further investigate the clinical impression that mental stress exacerbates pain in patients with chronic musculoskeletal pain.

Blink reflex R2 amplitudes in cervicogenic headache, chronic tension-type headache and migraine

Blink reflex R2 amplitude was investigated in seven patients with cervicogenic headache (CEH), 12 patients with chronic tension-type headache, 23 patients with migraine (10 with aura) and 17 headache-free controls. Standard electrical stimulation of the supraorbital nerve was applied and the response was recorded from the ipsilateral and the contralateral orbicularis oculi muscles. Low R2 amplitude was found in CEH patients compared with control subjects. Headache is unilateral in CEH and the ipsilateral and contralateral responses after stimulation on the painful side were most depressed. R2 amplitude was not significantly affected in migraine and tension headache patients. The results suggest that lower brainstem excitability is reduced in CEH. A state of hypoactivity may be present in caudal trigeminal nucleus neurons on the symptomatic side.

Examination of the diagnostic validity of 'headache attributed to whiplash injury': a controlled, prospective study

Acute and chronic headache attributed to whiplash injury are new diagnostic entities in the International Classification of Headache Disorders, second edition. A main objective of the present study was to assess the validity of these nosologic entities by studying the headache pattern in an inception cohort of 210 rear-end car collision victims and in 210 matched controls. Consecutive drivers involved in rear-end collisions were identified from the daily records of the Traffic Police Department of Kaunas, Lithuania. A standard self-report questionnaire was sent to the drivers between 2 and 7 days after the collision, and their passengers were recruited as well. Headache and neck pain were evaluated within 7 days of the collision, at 2 months and 1 year after the collision. A control group of non-traumatized subjects received questionnaires at the time of the selection and 1 year later. Of the 75 collision victims who developed headache within the first 7 days of the collision, 37 had a clinical picture in accordance with the criteria for acute whiplash headache (i.e., concomitant neck pain) and 38 did not. For acute headache after collision, concomitant neck pain was of no relevance to the headache type or its course. In both these subgroups, migraine and tension-type headache could be diagnosed in similar proportions and the prognosis after 2 months and 1 year was also similar. Preexisting headache was a strong prognostic factor in both groups for both acute and chronic pain. Compared with the non-traumatized control group, the 1-year incidence of new or worsened headache, or of headache improvement, was the same. A likely interpretation of the data is that acute headaches after rear-end car collisions mainly represent episodes of a primary headache precipitated by the stress of the situation. We conclude that the nosologic validity of both acute and chronic whiplash headache is poor as the headaches, in accordance with the criteria lack distinguishing clinical features and have the same prognosis compared with headaches in a control group.

A controlled prospective inception cohort study on the post-concussion syndrome outside the medicolegal context

In an earlier historical cohort study on the post-concussion syndrome (PCS) in Lithuania, a country in which there are few confounding factors, the validity of this condition as a disease entity could not be confirmed. In order to register the post-traumatic symptoms, the influence of sociodemographic factors, and the effect of expectation on these symptoms more reliably, we performed a controlled prospective study. Three hundred subjects with concussion were followed up with repeated questionnaires for 1 year. For each study subject, a sex- and age-matched control person with minor non-head injury was identified. These controls received similar questionnaires. Headache both after 3 months and after 1 year did not differ significantly between the head-injured participants and the non-head-injured controls. Several other symptoms attributed to PCS did not differ significantly between the groups after 3 months. After 1 year the vast majority of symptoms did not differ significantly. Exceptions were slightly significant differences concerning memory problems, concentration problems, dizziness and tiredness. These differences were insignificant when analysing symptoms in unmarried and/or people with lower education, separately. No relationship between cognitive dysfunction and the severity of concussion was found. Although the possibility of a mild organic brain injury cannot be completely ruled out, our results cast doubt on the validity of PCS as a useful clinical entity, at least for head injuries with loss of consciousness for <15 min. Sociodemographic factors and expectation seem to influence reporting of symptoms after concussion.

Neurophysiological tests and neuroimaging procedures in non-acute headache: guidelines and recommendations

The use of instrumental examinations in headache patients varies widely. In order to evaluate their usefulness, the most common instrumental procedures were evaluated, on the basis of evidence from the literature, by an EFNS Task Force (TF) on neurophysiological tests and imaging procedures in non-acute headache patients. The conclusions of the TF regarding each technique are expressed in the following guidelines for clinical use. 1 Interictal electroencephalography (EEG) is not routinely indicated in the diagnostic evaluation of headache patients. Interictal EEG is, however, indicated if the clinical history suggests a possible diagnosis of epilepsy (differential diagnosis). Ictal EEG could be useful in certain patients suffering from hemiplegic and basilar migraine. 2 Recording of evoked potentials is not recommended for the diagnosis of headache disorders. 3 There is no evidence to justify the recommendation of autonomic tests for the routine clinical examination of headache patients. 4 Manual palpation of pericranial muscles, with standardized palpation pressure, can be recommended for subdividing patient groups but not for diagnosis. Pressure algometry and electromyography (EMG) cannot be recommended as clinical diagnostic tests. 5 In adult and paediatric patients with migraine, with no recent change in attack pattern, no history of seizures, and no other focal neurological signs or symptoms, the routine use of neuroimaging is not warranted. In patients with atypical headache patterns, a history of seizures and/or focal neurological signs or symptoms, magnetic resonance imaging (MRI) may be indicated. 6 If attacks can be fully accounted for by the standard headache classification [International Headache Society (IHS)], a positron emission tomography (PET) or single-photon emission computerized tomography (SPECT) and scan will generally be of no further diagnostic value. 7 Nuclear medicine examinations of the cerebral circulation and metabolism can be carried out in subgroups of headache patients for diagnosis and evaluation of complications, when patients experience unusually severe attacks, or when the quality or severity of attacks has changed. 8 Transcranial Doppler examination is not helpful in headache diagnosis. Although many of the examinations described are of little or no value in the clinical setting, most of the tools have a vast potential for further exploring the pathophysiology of headaches and the effects of pharmacological treatment.

Electroencephalography in migraine: a review with focus on quantitative electroencephalography and the migraine vs. epilepsy relationship

EEG-studies in migraine in the last decade has contributed modestly to the understanding of headache pathogenesis. Headache patient groups seem to have increased EEG responses to photic stimulation, but a useful biological marker for migraine in single patients has not been found. In future EEG and QEEG studies we recommend to use follow-up designs and record several EEGs across the migraine cycle. It is also important to use a blinded study design in order to avoid selection bias. A clinical EEG should be performed in patients with acute headache attacks when either epilepsy, basilar migraine, migraine with prolonged aura or alternating hemiplegia is suspected. Unequivocal epileptiform abnormalities usually suggest a diagnosis of epilepsy. In children with occipital spike-wave activity the probable diagnosis is childhood epilepsy with occipital paroxysms (CEOP). The final diagnosis of either an epilepsy syndrome or migraine must be mainly based on a clinical judgement [corrected].

The validity of 'recognition-based' headache diagnoses in adolescents. Data from the Nord-Trøndelag Health Study 1995-97, Head-HUNT-Youth

The aim of this study was to evaluate the validity of the headache diagnoses (migraine and tension-type headache) obtained from short interviews by nurses, where the subjects were asked to identify their headache(s) based on recognition of typical headache descriptions. All students in junior high schools and high schools aged 12-19 years in Nord-Trøndelag county, Norway, were invited to participate in the youth part of the Nord-Trøndelag Health Study ('Helseundersøkelsen i Nord-Trøndelag'-HUNT), 1995-1997. In this cross-sectional study a total of 8984 students (88%) completed a comprehensive questionnaire with different health-related items. Of these, 6149 were also interviewed by nurses about their headache complaints by giving them two alternative headache descriptions in accordance with either migraine or tension-type headache (Head-HUNT-Youth). The headache diagnoses obtained from nurse interviews were validated in a stratified random sample enriched with headache subjects from the interviewed population. Out of 159 invited individuals, 112 (70%) participated in extensive semistructured interviews by neurologists. The overall chance-corrected agreement (kappa) was 0.76 (confidence interval (CI) 0.66-0.86), which is considered good. For migraine, the positive and negative predictive values were 89% and 90%, respectively, and the chance-corrected agreement (kappa) was 0.72 (CI 0.58-0.87). For tension-type headache, positive and negative predictive values were 83% and 91%, respectively, and chance-corrected agreement (kappa) was 0.74 (CI 0.62-0.87). There was good agreement between the headache diagnoses obtained from the short interviews by nurses and the extensive interviews by neurologists. Short interviews based on recognition of typical headache descriptions seem to be an alternative and efficient way to identify migraine and tension-type headache sufferers among adolescents. The method can be useful in epidemiological research, e.g. in estimation of headache prevalence.

Sleep apnoea and chronic headache

The objective of this study was to estimate prevalence of headache and body pain among patients referred for suspected sleep apnoea syndrome compared with the occurrence in a large population-based study (the Nord-Trøndelag Health Study). Between 1995 and 1998, ambulatory polysomnography was successfully performed in 421 consecutive patients, 324 of whom completed a questionnaire about sleep-related habits, headache and body pain. Headache and neck pain were more likely among patients admitted for polysomnography compared with the general population (n = 41 340). In the multivariate analyses, this association was mainly restricted to those with frequent complaints (> or =7 days per month). Chronic headache (headache > or = 15 days per month) was seven times more common among individuals with and without confirmed obstructive sleep apnoea syndrome than in the general population. There was no linear dose-response relationship between headache and neck pain and severity of apnoea or oxygen desaturation. Thus, hypoxia per se is less likely to explain the high headache prevalence among patients admitted for polysomnography.

A controlled historical cohort study on the post-concussion syndrome

In Lithuania, expectation of chronic symptoms after minor head injury is less than in western countries and possibilities for monetary compensation are minimal. Therefore, an opportunity exists to study the post-concussion syndrome (PCS) without several confounding factors present in western societies. We sent questionnaires about symptoms attributed to PCS to 200 subjects who had a concussion with loss of consciousness between 35 and 22 months before the study. For each study subject, a sex- and age-matched control person with minor non-head injury was identified. These controls received similar questionnaires. All the responding post-concussion patients stated that they had had acute headache after the trauma but this headache had disappeared in 96% of cases within 1 month. Headache and dizziness at the time of the questioning were not significantly more prevalent in the patients with concussion than in the controls, and there was no significant difference concerning subjective cognitive dysfunction. Scores of visual analogue scales of symptoms attributed to PCS showed no significant differences except for depression, alcohol intolerance and worry about brain injury, which were more frequent in the concussion group. No specific effect of the head injury was detected when various definitions and different constellations of core symptoms of PCS were used. These findings question the validity of the PCS as a useful clinical entity.

Clinical utility of EEG in alcohol-related seizures

OBJECTIVE

To study if electroencephalogram (EEG) can discriminate between alcohol-related seizures (ARS) and seizures unrelated to alcohol use.

MATERIAL AND METHODS

Alcohol-related seizures was defined as a seizure in a patient with score > or = 8 in the Alcohol Use Disorders Identification Test (AUDIT). Twenty-seven patients with ARS (22 without epilepsy: ARSwE), 21 AUDIT-negative epileptic patients with seizures (ES), and 30 other AUDIT negative patients with seizures (OS) were studied. Thirty-seven epilepsy outpatients and 79 sciatica inpatients were controls.

RESULTS

Epileptiform and slow activity were less frequent in the ARSwE than in the ES group. Alpha amplitude was lower in the ARSwE than the other groups. Photoparoxysmal activity was not observed. EEG was associated with a larger negative predictive value (78% probability of non-ARS if EEG was abnormal) than a positive predictive value (55% probability of ARS if EEG was normal).

CONCLUSION

A definitely abnormal EEG suggests epilepsy or symptomatic seizures unrelated to alcohol. The predictive value of a normal EEG is limited, but the typical post-ictal finding in ARS is nevertheless a normal low-amplitude EEG record.

[EEG after sleep deprivation in patients with suspected epilepsy]

BACKGROUND

The purpose of this study was to investigate to what extent sleep deprivation provokes epileptiform discharges in EEG in patients with suspected epilepsy.

MATERIAL AND METHODS

Data from 189 adults and children with unspecified seizures who had had EEG after sleep deprivation were evaluated retrospectively. Previous standard EEGs were without epileptiform discharges. The patients' final diagnosis were collected from the medical records.

RESULTS

13% of the patients demonstrated epileptiform activity in their sleep deprivation EEG, and significantly more epileptiform activity was found in patients with generalized tonic-clonic seizures and absences. None of the patients with a history of syncope showed epileptiform activity. The activation rate was higher in patients with an abnormal standard EEG compared to those with a normal standard EEG. The sensitivity of sleep deprivation EEG in this study was 35%, specificity 98% and positive predictive value 92%.

INTERPRETATION

Sleep deprivation EEG seems to have greatest diagnostic value in patients with generalized tonic-clonic seizures, absences and abnormal standard EEG.

Clinical and para-clinical tests in the routine examination of headache patients

Para-clinical examinations in the diagnosis and treatment control of headache patients vary considerably between clinics and headache centers. Among the neurological societies in Europe there has been a consensus that some common procedures and recommendations should be created. In the Fall of 1998, the European Federation of Neurological Societies (EFNS) commissioned a Task Force on Neurophysiological Tests and Imaging Procedures in Headache Patients. Members of the Task Force are the present authors and we have reviewed the literature on 1) neurophysiological tests (EEG and evoked potentials), 2) autonomic nervous system and clinical tests and 3) imaging and cerebrovascular tests (X-ray, CT, MR, fMRI, PET, SPECT and transcranial Doppler). The literature was carefully evaluated with respect to validity and strength of the data. The task was to reach conclusions about each technique in the form of guidelines for clinical use. Finally, selected areas for future research will be outlined. The extensive review and the guidelines will be published by the EFNS during 2000.

Familial mydriasis, cardiac arrhythmia, respiratory failure, muscular weakness and hypohidrosis

OBJECTIVES

To describe a family with some sort of progressive autonomic failure in one generation (2 affected of a sibship of 7 sisters). The main features were: mydriasis, cardiac arrhythmia, cardiomegaly, hypohidrosis, respiratory failure, and muscular weakness.

METHODS

Pupillometry, evaporimetry, and isokinetic power measurements were carried out.

RESULTS

The autonomic dysfunction pattern (mainly cardiac abnormalities, mydriasis) seems to differ somewhat from that of progressive autonomic failure (Shy-Drager syndrome). "Lewy body-like" inclusions were present, in particular in substantia nigra, but also in locus ceruleus and raphe nuclei (cell loss only in locus ceruleus). There were no oligodendroglial, cytoplasmatic inclusions, apparently a marker in multiple system atrophy. Proper Lewy bodies were also present. Differences seemed to prevail vs the Shy-Drager syndrome. Various traits: muscular weakness pattern (e.g. preferential peroneal distribution), minor elbow contractures, and arrhythmia were reminiscent of Emery-Dreifuss muscle dystrophy (E-D). Distinguishing features included: hereditary pattern, mydriasis, and hypohidrosis.

CONCLUSION

Conceivably, this disorder is close to, but still not identical with E-D.

Prophylactic treatment of migraine with angiotensin converting enzyme inhibitor (lisinopril): randomised, placebo controlled, crossover study

OBJECTIVE

To determine the efficacy of an angiotensin converting enzyme inhibitor in the prophylaxis of migraine.

DESIGN

Double blind, placebo controlled, crossover study.

SETTING

Neurological outpatient clinic.

PARTICIPANTS

Sixty patients aged 19-59 years with migraine with two to six episodes a month.

INTERVENTIONS

Treatment period of 12 weeks with one 10 mg lisinopril tablet once daily for one week then two 10 mg lisinopril tablets once daily for 11 weeks, followed by a two week wash out period. Second treatment period of one placebo tablet once daily for one week and then two placebo tablets for 11 weeks. Thirty participants followed this schedule, and 30 received placebo followed by lisinopril.

MAIN OUTCOME MEASURES

Primary end points: number of hours with headache, number of days with headache, number of days with migraine. Secondary end points: headache severity index, use of drugs for symptomatic relief, quality of life and number of days taken as sick leave, acceptability of treatment.

RESULTS

In the 47 participants with complete data, hours with headache, days with headache, days with migraine, and headache severity index were significantly reduced by 20% (95% confidence interval 5% to 36%), 17% (5% to 30%), 21% (9% to 34%), and 20% (3% to 37%), respectively, with lisinopril compared with placebo. Days with migraine were reduced by at least 50% in 14 participants for active treatment versus placebo and 17 patients for active treatment versus run-in period. Days with migraine were fewer by at least 50% in 14 participants for active treatment versus placebo. Intention to treat analysis of data from 55 patients supported the differences in favour of lisinopril for the primary end points.

CONCLUSION

The angiotensin converting enzyme inhibitor, lisinopril, has a clinically important prophylactic effect in migraine.

Visual, long-latency auditory and brainstem auditory evoked potentials in migraine: relation to pattern size, stimulus intensity, sound and light discomfort thresholds and pre-attack state

We aimed to estimate primary sensory evoked potential (EP) amplitude, amplitude-intensity functions and habituation in migraine patients compared with healthy control subjects and to investigate the possible relation to check size, sound and light discomfort thresholds, and the time to the next attack. Amplitudes of cortical visual evoked potentials (VEP, check size 8' and 33'), cortical long latency auditory evoked potential (AEP NIP1; 40, 55 and 70 dB SL tones) and brainstem auditory evoked potential (BAEP wave IV-V; 40, 55 and 65 dB SL clicks) were recorded and analysed in a blind and balanced design. The difference between the response to the first and the second half of the stimulus sequence was used as a measure of habituation. Twenty-one migraine patients (16 women and five men, mean age 39.3 years, six with aura, 15 without aura) and 22 sex- and age-matched healthy control subjects were studied (18 women and four men, mean age 39.5 years). Low sound discomfort threshold correlated significantly with low levels of BAEP wave IV-V amplitude habituation (r = -0.30, P = 0.05). VEP an AEP amplitudes, habituation, and amplitude-intensity function (ASF) slopes did not differ between groups when ANOVA main factors were considered. Control group VEP habituation was found for small check stimuli (P = 0.04), while potentiation was observed for medium sized checks (P = 0.02). The eight migraine patients who experienced headache within 24 h after the test tended to have increased BAEP wave IV-V ASF slopes (P = 0.08). This subgroup did also have a significant VEP habituation to small checks (P = 0.04). No correlation was found between different modalities. These results suggest that: (i) VEP habituation/potentiation state and brainstem activatio state may depend on the attack-interval cycle in migraine; (ii) VEP habituation/ potentiation may depend on spatial stimulus frequency; (iii) phonophobia (and possibly photophobia) may depend more on subcortical (brainstem) function than on cortical mechanisms; (iv) low cortical preactivation in migraine could not be confirmed; (v) EP habituation and ASF analysis may reflect sensory modality-specific, not generalized, central nervous system states in migraine and healthy control subjects.