Involvement of the ipsilateral-to-the-pain anterior-superior hypothalamic subunit in chronic cluster headache.

BACKGROUND: Despite hypothalamus has long being considered to be involved in the pathophysiology of cluster headache, the inconsistencies of previous neuroimaging studies and a limited understanding of the hypothalamic areas involved, impede a comprehensive interpretation of its involvement in this condition. METHODS: We used an automated algorithm to extract hypothalamic subunit volumes from 105 cluster headache patients (57 chronic and 48 episodic) and 59 healthy individuals; after correcting the measures for the respective intracranial volumes, we performed the relevant comparisons employing logist regression models. Only for subunits that emerged as abnormal, we calculated their correlation with the years of illness and the number of headache attacks per day, and the effects of lithium treatment. As a post-hoc approach, using the 7 T resting-state fMRI dataset from the Human Connectome Project, we investigated whether the observed abnormal subunit, comprising the paraventricular nucleus and preoptic area, shows robust functional connectivity with the mesocorticolimbic system, which is known to be modulated by oxytocin neurons in the paraventricular nucleus and that is is abnormal in chronic cluster headache patients. RESULTS: Patients with chronic (but not episodic) cluster headache, compared to control participants, present an increased volume of the anterior-superior hypothalamic subunit ipsilateral to the pain, which, remarkably, also correlates significantly with the number of daily attacks. The post-hoc approach showed that this hypothalamic area presents robust functional connectivity with the mesocorticolimbic system under physiological conditions. No evidence of the effects of lithium treatment on this abnormal subunit was found. CONCLUSIONS: We identified the ipsilateral-to-the-pain antero-superior subunit, where the paraventricular nucleus and preoptic area are located, as the key hypothalamic region of the pathophysiology of chronic cluster headache. The significant correlation between the volume of this area and the number of daily attacks crucially reinforces this interpretation. The well-known roles of the paraventricular nucleus in coordinating autonomic and neuroendocrine flow in stress adaptation and modulation of trigeminovascular mechanisms offer important insights into the understanding of the pathophysiology of cluster headache.

Efficacy of mindfulness added to treatment as usual in patients with chronic migraine and medication overuse headache: a phase-III single-blind randomized-controlled trial (the MIND-CM study).

BACKGROUND: Mindfulness gained considerable attention for migraine management, but RCTs are lacking. We aimed to assess the efficacy of a six-sessions mindfulness-based treatment added to treatment as usual (TaU) in patients with Chronic Migraine (CM) and Medication Overuse Headache (MOH) on headache frequency, medication intake, quality of life, disability, depression and anxiety, cutaneous allodynia, awareness of inner states, work-related difficulties, and disease cost. METHODS: In this Phase-III single-blind RCT carried out in a specialty Italian headache center, 177 patients with CM and MOH were randomized 1:1 to either TaU (withdrawal from overused drugs, education on proper medication use and lifestyle issues, and tailored prophylaxis) or mindfulness-based intervention added to TaU (TaU + MIND). The mindfulness-based intervention consisted of six group session of mindfulness practice and 7-10 min daily self-practice. The primary endpoint was the achievement of ≥ 50% headache frequency reduction at 12 months compared to baseline, and was analyzed on an intention-to-treat principle using Pearson's Chi-Squared test. Secondary endpoints included medication intake, quality of life (QoL), disability, depression and anxiety, cutaneous allodynia, awareness of inner states, work-related difficulties, and disease cost. The secondary endpoints were analyzed using per-protocol linear mixed models. RESULTS: Out of the 177 participants 89 were randomized to TaU and 88 to TaU + MIND. Patients in the TaU + MIND group outperformed those in TaU for the primary endpoint (78.4% vs. 48.3%; p < 0.0001), and showed superior improvement in headache frequency, QoL and disability, headache impact, loss of productive time, medication intake, and in total, indirect and direct healthcare costs. CONCLUSIONS: A mindfulness-based treatment composed of six-week session and 7-10 min daily self-practice added on to TaU is superior to TaU alone for the treatment of patients with CM and MOH. TRIAL REGISTRATION: MIND-CM was registered on clinicaltrials.gov (NCT03671681) on14/09/2018.

Stereotactic electroencephalography in humans reveals multisensory signal in early visual and auditory cortices.

Unequivocally demonstrating the presence of multisensory signals at the earliest stages of cortical processing remains challenging in humans. In our study, we relied on the unique spatio-temporal resolution provided by intracranial stereotactic electroencephalographic (SEEG) recordings in patients with drug-resistant epilepsy to characterize the signal extracted from early visual (calcarine and pericalcarine) and auditory (Heschl's gyrus and planum temporale) regions during a simple audio-visual oddball task. We provide evidences that both cross-modal responses (visual responses in auditory cortex or the reverse) and multisensory processing (alteration of the unimodal responses during bimodal stimulation) can be observed in intracranial event-related potentials (iERPs) and in power modulations of oscillatory activity at different temporal scales within the first 150 msec after stimulus onset. The temporal profiles of the iERPs are compatible with the hypothesis that MSI occurs by means of direct pathways linking early visual and auditory regions. Our data indicate, moreover, that MSI mainly relies on modulations of the low-frequency bands (foremost the theta band in the auditory cortex and the alpha band in the visual cortex), suggesting the involvement of feedback pathways between the two sensory regions. Remarkably, we also observed high-gamma power modulations by sounds in the early visual cortex, thus suggesting the presence of neuronal populations involved in auditory processing in the calcarine and pericalcarine region in humans.

The neural correlates of lexical processing in disorders of consciousness.

There is a growing interest in the use of functional imaging to assess brain activity in the absence of behavioural responses in patients with disorders of consciousness (DOC). In the present study, we applied a hierarchical auditory stimulation paradigm to functional magnetic resonance (fMRI) in a group of long-term DOC adult patients. Brain response to pairs of pseudowords, of unrelated words and of semantically related words, i.e. stimuli differing in lexical status (words vs. pseudowords) and semantic relatedness (related vs. unrelated) was assessed. The former contrast was considered to reflect the automatic brain response to the passive presentation of meaningful real words, while the latter aimed to assess the response to meaning relationships. The results of the study indicate that automatic lexical processing can be observed in minimally conscious state (MCS), but also in vegetative state/unresponsive wakefulness syndrome (VS/UWS) patients, as indicated by increase in blood oxygenation level dependent (BOLD) activity in the linguistic networks. DOC patients, for some task conditions, recruited additional areas in comparison to healthy participants. Furthermore this study provides additional evidence of the potential role of fMRI in the assessment of residual cognitive processing in some of these patients, which may not be evident at the clinical level.