Cervicogenic headache: electronystagmography, perception of verticality and posturography in patients before and after C2-blockade

Unbounded evidence accumulation characterizes subjective visual vertical forced-choice perceptual choice and confidence

Humans can subjectively yet quantitatively assess choice confidence based on perceptual precision even when a perceptual decision is made without an immediate reward or feedback. However, surprisingly little is known about choice confidence. Here we investigate the dynamics of choice confidence by merging two parallel conceptual frameworks of decision making, signal detection theory and sequential analyses (i.e., drift-diffusion modeling). Specifically, to capture end-point statistics of binary choice and confidence, we built on a previous study that defined choice confidence in terms of psychophysics derived from signal detection theory. At the same time, we augmented this mathematical model to include accumulator dynamics of a drift-diffusion model to characterize the time dependence of the choice behaviors in a standard forced-choice paradigm in which stimulus duration is controlled by the operator. Human subjects performed a subjective visual vertical task, simultaneously reporting binary orientation choice and probabilistic confidence. Both binary choice and confidence experimental data displayed statistics and dynamics consistent with both signal detection theory and evidence accumulation, respectively. Specifically, the computational simulations showed that the unbounded evidence accumulator model fits the confidence data better than the classical bounded model, while bounded and unbounded models were indistinguishable for binary choice data. These results suggest that the brain can utilize mechanisms consistent with signal detection theory-especially when judging confidence without time pressure.NEW & NOTEWORTHY We found that choice confidence data show dynamics consistent with evidence accumulation for a forced-choice subjective visual vertical task. We also found that the evidence accumulation appeared unbounded when judging confidence, which suggests that the brain utilizes mechanisms consistent with signal detection theory to determine choice confidence.

Vestibular disorders following different types of head and neck trauma

This review focuses on the published literature on vestibular disorders following different types of head and neck trauma. Current knowledge of the different causes and underlying mechanisms of vestibular disorders, as well as the sites of organic damage, is presented. Non-organic mechanisms are also surveyed. The frequency of occurrence of vestibular symptoms, and of other accompanying subjective complaints, associated with different types of trauma is presented and related to the specific causes. Hypotheses about the pathogenesis of traumatic vestibular disorders are presented, and the knowledge derived from animal experiments is also discussed. We believe this to be a very important topic, since vestibular complaints in traumatic patients often remain undiagnosed or underestimated in clinical practice. This review article aims to suggest directions for additional research and to provide guidance to both the scientific and clinical practice communities.

Impaired postural control in patients affected by tension-type headache

Sixteen subjects, affected by chronic tension-type headache (TTH) accordingly to the International Headache Society Classification (1988) criteria, in presence of tenderness in pericranial muscles,with a mean age of 37+/-11.8 years, and ten healthy volunteer subjects, age and sex matched, were submitted to postural analysis by Static Posturography (S.Ve.P. Amplaid). Aim of the study was to evaluate whether patients with TTH have disturbed postural control, as compared to normal subjects. Postural analysis considered all posturographic variables but focused on spectral frequency analysis of body sway. In both open (OE) and closed eyes (CE) condition, spectral frequency analysis showed a significantly increased body sway at low (OE= p < or = 0.01; CE= p < or = 0.01) and middle (OE= p < or = 0.01; CE= p < or = 0.01) frequencies on the antero-posterior (y) plane and at low frequencies (OE= p < or = 0.05; CE= p < or = 0.05) on the lateral (x) plane. Statistical analysis was performed using the Student's t test for unpaired data, p value 0.05 defined significant. The proprioceptive input seems to be predominant at middle and high frequencies in maintaining posture, our results seem then to suggest a proprioceptive disturbance in TTH patients. The disturbance is likely related to chronic pericranial muscle contraction and tenderness. Posturography and spectral analysis may help not only in the diagnosis of a postural disturbance but even more in the follow-up of TTH patients, during and after a medical and/or a rehabilitative treatment.

[Medicolegal assessment of post-traumatic vertigo]

Post-traumatic vertigo refers to a group of different disorders which occur following trauma, mainly closed head injury and whiplash injury of the cervical spine. Aside from headaches, vertigo is the most common symptom in this group of patients. In general, there are two main groups of patients with post-traumatic vertigo: those with documented vestibular dysfunctions and those without. The most common post-traumatic vestibular disorders are benign paroxysmal positioning vertigo, labyrinthine concussion, canal dehiscence and otolithic lesions. Some of these disorders are characterized by spontaneous improvement or recovery over weeks or months and some may also be treated effectively. A number of patients, however, develop phobic postural vertigo requiring psychiatric or psychosomatic exploration.

Pulsed radiofrequency of the second cervical ganglion (C2) for the treatment of cervicogenic headache

In this case series report, two patients with cervicogenic headache were selected. After initial positive response to the greater occipital nerve block, pulse radiofrequency (PRF) was performed on the position of the second cervical ganglion (C2). Two patients reported 100% pain relief lasting for 6 months. The lateral puncture is safer and more comfortable than the posterior site. This case study demonstrates the effectiveness of PRF to treat cervicogenic headache originating from the C2 nerve. However, we need to further evaluate the results using more samples.

Influence of cervical spine stabilization via Stiff Neck on the postural system in healthy patients: compensation or decompensation of the postural system?

Functional and structural disorders of the cervical spine are often regarded as the cause of non-specific vertigo. Pathogenetically, disorders of proprioceptive connections between neck muscles and vestibular cores as well as the proprioceptors in the cervical facette joints are presumed. According to a study by Hülse and Hölzl (HNO 48:295-301, 1), after manual therapeutic intervention in patients with functional disorders of the cervical spine 50% of the probands stated a significant reduction of their vertigo. This was backed up in posturography, which documented an improvement in vestibulospinal reactions. To date, the effects of artificial as well as surgical stabilization of the cervical spine on the balance system have not been explored yet. In a first pilot study, we examined the influence of artificial stabilization of the cervical spine via cervical collar Stiff Neck, manufactured by Ambu/Perfit ACE] on the balance system of 20 healthy probands. For this purpose, a posturography (Balance Master Systems, NeuroCom, Clackamas, OR, USA) was applied to 20 healthy probands (10 males, 10 females) with a mean age of 35 years who had no prior spine pathology. Posturography was analyzed under static and dynamic test situations with and without Stiff Neck cervical collar. The results were compared statistically to the Wilcoxon test. In the static test situation of the modified clinical test of sensory interaction on balance, a significantly improved standing stability occurred. In none of the dynamic tests did fixation of the cervical spine by Stiff Neck cuff lead to a measurable impairment of the movement coordination. All probands felt subjectively more stable when wearing the Stiff Neck. In healthy probands, a fixation of the cervical spine leads to a stabilization of the postural balance situation. This fixation seems to be helpful in compensating the malfunction of other components of balance information. In a next step, this same model of analysis is applied to patients with cervical instability. Standing stability and movement coordination before and after cervical fusion are being explored.

[Benign paroxysmal positional vertigo with and without manifest positional nystagmus: an 18-month follow-up study of 70 patients]

BACKGROUND

In this follow-up study of approximately 18 months we assessed parameters of medical management in a sample of 70 patients suffering from benign paroxysmal positional vertigo.

METHODS

Apart from demographic data, we evaluated the time interval from the appearance of the first symptoms until a diagnostic positional manoeuvre was performed, the efficacy of liberatory manoeuvres, the prescription of medication, the use of technical diagnostic resources and the relapse rate.

RESULTS

None of the patients had received a diagnostic positioning test until then. Moreover, in one out of three cases a further unnecessary technical diagnostic procedure was carried out. There was a tendency for the right labyrinth to be more frequently affected, a fact that was statistically independent from age and sex, as well as from overall prognosis, which was characterized by a 15.6% recurrence rate. All patients with manifest positional nystagmus were successfully treated: 87.2% immediately after the repositioning manoeuvre and the rest within 10 days by self-performing Brandt-Daroff exercises. Our retrospective analysis revealed that, given a normal neuro-otological examination, a typical medical history without manifest positioning nystagmus leads safely to the correct diagnosis.

CONCLUSION

The delay between the onset of symptoms and the diagnosis of BPPV is very often unduly long. A focused medical history may be diagnostic even in the absence of nystagmus during the Dix-Hallpike manoeuvre.

Causes of persistent postoperative headache after surgery for vestibular schwannoma

Our aim was to elucidate the aetiology of persistent postoperative headache, a common sequel for several years after vestibular schwannoma surgery through the retrosigmoid approach. Twenty-seven patients with reported major postoperative headache were tested for vestibular responses and cervico-collic reflexes. The role of local anaesthesia injected into the neck muscle insertions or around the occipital nerves was evaluated. Sixteen patients operated on for vestibular schwannoma, but without headache, and 12 healthy volunteers served as control groups. Vestibular responses and cervico-collic reflexes deteriorated equally in the patients regardless of whether or not they had a postoperative headache. Local anaesthesia did not alter the results. The posturography results were increased among both patient groups. Sumatriptan alleviated pain in nine patients and abolished it completely in one out of these nine patients. Vestibular imbalance or abnormal activation of neck muscles do not explain postoperative headache. Occipital nerve entrapment or neuralgia explains the headache in a few patients. The relatively pronounced sumatriptan effect may, however, suggest a trigeminal nerve mediated cause for postoperative headache.

Vestibular schwannoma surgery and headache

The aim of the study was to evaluate aetiological factors for postoperative headache after vestibular schwannoma (VS) surgery with respect to asymmetric activation of vestibular reflexes. After surgery, 27 VS patients with persistent postoperative headache, 16 VS patients without headache and 9 healthy controls were examined. The vestibular, cervicocollic and cervicospinal reflexes were evaluated to study whether asymmetric activation of vestibular reflexes could cause headache. The effect of neck muscle and occipital nerve anaesthesia and the effect of sumatriptan on headache were also evaluated. The vestibular function of VS patients with headache did not differ from that of VS patients without headache, but was abnormal when compared to that of normal controls. The cervicospinal and cervicocollic reflexes did not differ in the patient groups. Injection of lidocaine around the operation scar gave pain relief to two patients, and one of them had occipital nerve entrapment. Infiltration of lidocaine deep in the neck muscles in the vicinity of the C2 root did not alleviate headache, but caused vertigo. Nine patients with musculogenic headache got pain relief from supportive neck collars, and two patients with cervicobrachial syndrome got pain relief from manual neck traction. The study shows that asymmetric activation of cervicocollic reflexes does not seem to be the reason for headache. Headache seems to be linked to neuropathic pain, allegedly caused by trigeminal irritation of the inner ear and the posterior fossa, which has recently been linked to vascular pain.

Cervicogenic headaches: a critical review

BACKGROUND CONTEXT

The notion that headaches may originate from disorders of the cervical spine and can be relieved by treatments directed at the neck is gaining recognition among headache clinicians but is often neglected in the spine literature.

PURPOSE

To review and summarize the literature on cervicogenic headaches in the following areas: historical perspective, diagnostic criteria, epidemiology, pathogenesis, differential diagnosis, and treatment.

STUDY DESIGN/SETTING

A systematic literature review of cervicogenic headache was performed.

METHODS

Three computerized medical databases (Medline, Cumulative Index to Nursing and Allied Health Literature [CINAHL], Mantis) were searched for the terms "cervicogenic" and "headache." After cross-referencing, we retrieved 164 unique citations; 48 citations were added from other sources, for a total of 212 citations, although all were not used.

RESULTS

Hilton described the concept of headaches originating from the cervical spine in 1860. In 1983 Sjaastad introduced the term "cervicogenic headache" (CGH). Diagnostic criteria have been established by several expert groups, with agreement that these headaches start in the neck or occipital region and are associated with tenderness of cervical paraspinal tissues. Prevalence estimates range from 0.4% to 2.5% of the general population to 15% to 20% of patients with chronic headaches. CGH affects patients with a mean age of 42.9 years, has a 4:1 female disposition, and tends to be chronic. Almost any pathology affecting the cervical spine has been implicated in the genesis of CGH as a result of convergence of sensory input from the cervical structures within the spinal nucleus of the trigeminal nerve. The main differential diagnoses are tension type headache and migraine headache, with considerable overlap in symptoms and findings between these conditions. No specific pathology has been noted on imaging or diagnostic studies which correlates with CGH. CGH seems unresponsive to common headache medication. Small, noncontrolled case series have reported moderate success with surgery and injections. A few randomized controlled trials and a number of case series support the use of cervical manipulation, transcutaneous electrical nerve stimulation, and botulinum toxin injection.

CONCLUSIONS

There remains considerable controversy and confusion on all matters pertaining to the topic of CGH. However, the amount of interest in the topic is growing, and it is anticipated that further research will help to clarify the theory, diagnosis, and treatment options for patients with CGH. Until then, it is essential that clinicians maintain an open, cautious, and critical approach to the literature on cervicogenic headaches.

Headache and the cervical spine: a critical review

Headache related to the cervical spine is often misdiagnosed and treated inadequately because of confusing and varying terminology. Primary headaches such as tension-type headache and migraine are incorrectly categorized as "cervicogenic" merely because of their occipital localization. Cervicogenic headache as described by Sjaastad presents as a unilateral headache of fluctuating intensity increased by movement of the head and typically radiates from occipital to frontal regions. Definition, pathophysiology; differential diagnoses and therapy of cervicogenic headache are demonstrated. Ipsilateral blockades of the C2 root and/or greater occipital nerve allow a differentiation between cervicogenic headache and primary headache syndromes such as migraine or tension-type headache. Neither pharmacological nor surgical or chiropractic procedures lead to a significant improvement or remission of cervicogenic headache. Pains of various anatomical regions possibly join into a common anatomical pathway, then present as cervicogenic headache, which should therefore be understood as a homogeneous but also unspecific pattern of reaction.