Transcranial Doppler: technique and application to headache

Establishing continuum in Transcranial Doppler characteristics of IIH, migraine and healthy controls- An exploratory study

BACKGROUND

IIH is a severe form of headache that often has superimposed migraine and often it is very difficult to distinguish the two forms of headache. Intracranial hemodynamics is a relatively unexplored means of distinguishing between the two forms of headache.

OBJECTIVES

We aimed to study intracranial flow dynamics using Transcranial Doppler in patients with IIH, migraine, and normal controls.

MATERIALS AND METHODS

It was a hospital-based observational study that included 51 people with IIH, 87 people with migraine, and 101 healthy controls and all were subjected to TCD study after detailed clinical examination.

RESULTS

Mean age of patients in three groups were similar with the mean age in IIH being 33.41 ± 10.75 (age in years ± SD). Vision loss was present in 66.67% of patients with IIH, and most common field defect was generalized constriction (27.5%). Neuroimaging was abnormal in 94.11% of patients of IIH with mean CSF pressure was 31.27±5.32 cm of water. Of all the TCD-measured velocities, mean flow velocity (MFV) showed a significant difference in all three groups with (p-value <0.001). The pulsatility index, both for middle cerebral arteries as well as ophthalmic arteries showed a significant difference in the three groups with the highest values in IIH patients (p-value<.001). The mean VMR in IIH (1.11±0.32) was lower than the mean VMR in migraine (1.34±0.43) as well as controls (1.49±0.46).

CONCLUSION

TCD parameters like MFV and PI are useful parameters that show considerable variation and can be used to differentiate between IIH and migraine.

A transcranial doppler study in interictal migraine and tension-type headache

PURPOSE

To use transcranial Doppler (TCD) sonography to determine if patients with migraine without aura have interictal hemodynamic abnormalities compared with patients who have episodic tension-type headache (TH).

METHODS

Thirty-six migraine patients without aura and 51 TH patients (age range, 16-50 years) who were diagnosed according to the criteria of the International Headache Society 1988 participated in the study. Forty-four healthy volunteers, matched for age and sex, formed the control group. Time-averaged mean velocity (TAMV), pulsatility index (PI), and breath-holding index (BHI) were measured via TCD sonography in the middle cerebral artery.

RESULTS

TAMV was higher in migraine without aura than in episodic TH (p = 0.034). There were no differences between groups regarding PI or BHI.

CONCLUSION

Our findings support the arteriolar vasodilatation theory in migraine without aura.

Asymmetric scalp distribution of pattern visual evoked potentials during interictal phases in migraine

The N70 and P100 components of transient pattern visual evoked potentials (P-VEPs) were measured in migraine patients, with and without aura, and in normal subjects in order to evaluate their latency, amplitude and occipital scalp distribution. The aim was to find any typical electrophysiological abnormalities in migraine. P-VEP N70 and P100 were analyzed in 59 patients without any known visual field defect. Mean latency and amplitude values were within normal ranges for either N70 and P100 all over the occipital scalp; the only significant abnormality we found was related to the absolute right-left amplitude ratio either for N70 and P100 waves, providing an asymmetry in P-VEP scalp distribution; this finding was detected in 78.9% of patients with aura and 72.5% without aura. Our results show that in migraine patients, both P-VEP waves N70 and P100, have an asymmetric topographic distribution, even during interictal phases, that can be explained by a cortical disturbance in agreement with the neural hypothesis of headache.

The pharmacodynamics of sumatriptan in nitroglycerin-induced headache

Migraine is a common disorder that causes significant morbidity in those afflicted. Many novel antimigraine compounds are in clinical development, yet full characterization of each one's pharmacodynamic behavior is a formidable task due to the difficulty in studying a migraineur during an attack. Nitroglycerin (NTG) administration commonly causes a headache with some features similar to those of a migraine. As such, NTG has been used as a model of vascular headaches, including migraine. The pharmacodynamic effects of nitroglycerin and sumatriptan on middle cerebral artery blood flow velocity (MCAv) and headache scores were studied in 10 healthy male volunteers. An intravenous infusion of NTG titrated to 0.5 mcg/kg/min over 30 minutes resulted in a median reduction from baseline in MCAv of 27% (range: 16.4%-37.3%). Nine of the subjects developed a headache with a median verbal score of 3.5 of 10 (range: 0-5). Subjects received sumatriptan either 2 mg intravenously or 6 mg subcutaneously, which abated clinical headache in 9 of the 10 subjects (p = 0.030). A median sumatriptan-induced increase in MCAv of 21% (p = 0.054) suggested a constricting effect on the NTG-induced dilated MCA. A two-compartment pharmacokinetic/indirect-effects pharmacodynamic model was fit to the sumatriptan concentration and MCAv data using iterative two-stage analysis. This model was unbiased and fit the concentration (r2 = 0.98) and the MCAv (r2 = 0.79) data well. These results suggest that NTG-induced headache and the development of pharmacokinetic/pharmacodynamic models could serve as a useful method for exploring the mechanisms of abortive migraine drugs.

Cerebrovascular CO2 reactivity in migraine with aura and without aura. A transcranial Doppler study

INTRODUCTION

We studied by means of Transcranial Doppler (TCD) recordings the CO2 cerebrovascular reactivity in migraine patients during the headache-free period.

MATERIAL & METHODS

In three groups of subjects (15 controls, 15 suffering from migraine with aura and 15 from migraine without aura) the middle cerebral artery (MCA) mean flow velocity (MFV) was recorded under basal condition and hypocapnia induced by hyperventilation. Relative MFV, PI (Pulsatility Index) changes and Reactivity Index (RI) were calculated.

RESULTS

Reactivity Index values were: 0.019 +/- 0.007 (mean +/- SD) in control subjects: 0.029 +/- 0.008 in migraine with aura; 0.022 +/- 0.008 in migraine without aura. Statistical analysis showed a significantly (P < 0.05) increased RI in migraine with aura group.

CONCLUSION

Cerebrosvascular CO2 reactivity is increased during the interictal period in migraine with aura patients.

Estimation of cerebrovascular reactivity in migraine without aura

BACKGROUND AND PURPOSE

The nature and role of vascular abnormalities in migraine are controversial. In this study we evaluated cerebrovascular reactivity to hypercapnia in patients suffering from migraine without aura with unilateral headache.

METHODS

Using bilateral transcranial Doppler ultrasound, we studied the changes of flow velocity after hypercapnia in the anterior, middle, and posterior cerebral arteries of 16 migraine patients and 16 healthy control subjects. All patients were studied during an attack-free interval and during a migraine attack. Cerebrovascular reactivity was evaluated with the breath-holding index, obtained by dividing the percent increase in mean flow velocity occurring during breath-holding by the time (seconds) in which the subjects held their breath after a normal inspiration.

RESULTS

The response to breath-holding was similar for all arteries considered in both control subjects and patients during the attack-free interval. During the migraine attack, the breath-holding index in patients was significantly lower than the migraine-free interval in all arteries (P < .001). No side-to-side difference in cerebrovascular reactivity was detected in migraine patients either outside or during attacks.

CONCLUSIONS

These results suggest that a failure of cerebrovascular regulation occurs during attacks of migraine without aura.

The physiological stress response and the role of cognitive coping in migraine patients and non-headache controls

Our study investigated physiological response specificity and cognitive coping in migrainous patients during an achievement task situation. Thirty-three migrainous subjects and thirty-two non-headache controls were subjected to 40 min of demanding cognitive tasks and 20 min of recovery during which cranial and peripheral vasomotor responses were registered as well as electrodermal and myographic activity. Subjects of both groups were randomly assigned to two experimental conditions, a so-called 'spontaneous processing condition' and the 'positive coping treatment'. In this treatment condition subjects received a short training in the conscious use of positive self-statements in stress situations. Though a specific pattern of cranial vasomotor responses in migraine subjects could be verified by group statistics, this pattern was only found in very few individuals. Reliable differences between groups could not be identified in other physiological variables either. The hypothesis that the predicted cranial vasomotor specificity in migraine subjects correlates with negative cognitive coping habits in migraine subjects best revealed in the 'spontaneous processing' condition, was not corroborated. The treatment variation regarding coping produced somewhat paradoxical effects, more relaxed and positive self-evaluation (subjective level) and more arousal (physiological level). Results are discussed for their impact on the psycho-biological model of migraine.