The neural basis of somatosensory temporal discrimination threshold as a paradigm for time processing in the sub-second range: An updated review.

BACKGROUND AND OBJECTIVE: The temporal aspect of somesthesia is a feature of any somatosensory process and a pre-requisite for the elaboration of proper behavior. Time processing in the milliseconds range is crucial for most of behaviors in everyday life. The somatosensory temporal discrimination threshold (STDT) is the ability to perceive two successive stimuli as separate in time, and deals with time processing in this temporal range. Herein, we focus on the physiology of STDT, on a background of the anatomophysiology of somesthesia and the neurobiological substrates of timing. METHODS: A review of the literature through PubMed & Cochrane databases until March 2023 was performed with inclusion and exclusion criteria following PRISMA recommendations. RESULTS: 1151 abstracts were identified. 4 duplicate records were discarded before screening. 957 abstracts were excluded because of redundancy, less relevant content or not English-written. 4 were added after revision. Eventually, 194 articles were included. CONCLUSIONS: STDT encoding relies on intracortical inhibitory S1 function and is modulated by the basal ganglia-thalamic-cortical interplay through circuits involving the nigrostriatal dopaminergic pathway and probably the superior colliculus.

Concurrent tonic pupil and trochlear nerve palsy in COVID-19.

Since COVID-19 was first reported, different neurological complications have been acknowledged, but their description is constantly evolving. We report a case of concurrent tonic pupil and trochlear nerve palsy in this context. A 62-year-old man reported a 5-day history of binocular vertical diplopia and blurred vision in his left eye, noticing that his left pupil was dilated. He had suffered a flu-like syndrome 2 weeks before. Clinical exam showed a right trochlear nerve palsy and a left mydriatic pupil. MRI, X chest ray, and analytical results were normal. Antibodies for SARS-CoV-2 were positive (low IgM and high IgG titers). Antiganglioside antibodies were negative. A 0.125% pilocarpine test confirmed Adie's pupil diagnosis. The patient was treated with a tapered prednisone dose with resolution of his diplopia but no change in Adie's pupil. This is the first case reporting Adie's pupil as a postinfectious manifestation of COVID-19. An immune-mediated mechanism is presumed.

Transcutaneous Supraorbital Stimulation as a Preventive Treatment for Chronic Migraine: A Prospective, Open-Label Study.

BACKGROUND AND OBJECTIVE: Successful preventive treatment in chronic migraine (CM) remains an unmet need in some cases, and new therapeutic strategies are emerging. We aimed to test the effect of noninvasive, transcutaneous supraorbital nerve stimulation (tSNS) in a group of patients with CM. PATIENTS AND METHODS: This was an open label, quasi-experimental design. Twenty-five CM patients were recruited from two hospital headache clinics. After a one-month baseline period, monthly visits were scheduled during three months. Headache occurrence, its intensity, and symptomatic medication intake were recorded through a diary kept by each patient. Both a per-protocol analysis and an intention-to-treat analysis were performed for the main outcome measures. RESULTS: Twenty-one and 24 patients were included in the per-protocol and the intention-to-treat analyses, respectively. In the per-protocol analysis, a significant four-day decrease in the mean monthly days with moderate or severe headache was observed from baseline to the end of the study (t test, P = 0.0163), and there was a nonsignificant reduction of 2.95 in the mean monthly total headache days. In the intention-to-treat analysis, a nonsignificant 3.37 reduction in the mean monthly days with moderate or severe headache was observed for the same period, and there was a significant 2.75 reduction in the mean monthly days with any headache (t test, P = 0.016). CONCLUSIONS: tSNS could hold preventive properties in the treatment of CM, but the effect may be either mild or controversial. Double blind, sham-controlled studies are essential to confirm these findings and to outline their clinical relevance in the CM therapeutic scenario.

Stress, Coping, and Personality in Patients with Epicrania Fugax, and Their Relation to the Clinical Characteristics of Pain.

Objective: The aim of the present work is to analyze certain psychological features in a group of patients diagnosed with Epicrania fugax (EF; that has been recently included in the appendix of the International Classification of Headache Disorders, third edition, beta version), as well as their association with diverse demographic and clinical characteristics of the sample. Design: Case-control. Method: Perceived Stress Scale (PSS), Stress Coping (COPE), Big Five Personality Traits (NEO-FFI), Depression (BDI-II), and Trait Anxiety (STAI) were evaluated in 23 patients with EF and 23 matched healthy controls. Differences between EF patients and controls were analyzed using the Mann-Whitney U test. Differences in psychological features as a function of the demographic and clinical characteristics were examined using one-way Analysis of Variance (ANOVA), Mann-Whitney U test, or Pearson's correlations. Results: The two groups differed significantly from each other in Denial, Trait anxiety, and Depression. Low-frequency epicrania patients scored significantly higher than controls in Perceived stress, Neuroticism, Denial, Self-blame, Trait anxiety, and Depression and higher than high-frequency EF in Venting. Conclusions: The results initially suggest the absence of substantial differences between patients suffering of EF and healthy controls. On the contrary, low-frequency EF patients show a distinctive "negative (unhealthy) psychological profile," in opposition to high-frequency EF patients. This circumstance highlights the potential need to consider low- frequency EF patients as a target for psychological intervention in combination with the most common medical procedures. Longitudinal studies are necessary to correctly elucidate the influence of these psychological variables on the course of EF.

Pain Paroxysms With Coronal Radiation: Case Series and Proposal of a New Variant of Epicrania Fugax.

OBJECTIVE: We aim to report 4 patients with brief pain paroxysms whose clinical features remind of typical epicrania fugax (EF), except for the direction along a transverse trajectory. BACKGROUND: EF has been defined as a brief paroxysmal head pain, with stabbing quality, describing a linear or zig-zag trajectory across the surface of one hemicranium. METHODS: We considered all patients attending the headache outpatient office at 3 tertiary hospitals from March 2008 to December 2015. We identified a total of 4 cases with dynamic pain paroxysms moving in coronal direction. RESULTS: The mean age at onset was 49 years (range 34-75). All the patients suffered a dynamic pain from parietal or temporal areas to the contralateral ones, crossing the midline in a linear or zig zag trajectory, the entire sequence lasting 2-3 seconds. No triggers were identified. One patient noticed mild interictal tenderness at the stemming point. The frequency of the attacks varied from 2 per week to 1 every 2 months. No underlying disorders were identified by physical and neurological exams and neuroimaging and laboratory tests. CONCLUSIONS: Our patients presented with a paroxysmal head pain that might correspond to a transverse variant of EF. These observations may not only expand the EF phenotype but also reinforce the distinction between EF and pericranial neuralgias.

Increase in body temperature during migraine attacks.

INTRODUCTION: Intermittent fever has been occasionally related to migraine, either as a migraine equivalent or as a migraine accompaniment. We present a case of recurrent increase in body temperature consistently associated with migraine headaches. METHODS: A 15-year-old girl reported a 3-year lasting history of migraine without aura, with a feeling of warmth occurring in each episode. Ancillary tests did not show any evidence of secondary headaches or any systemic disease. A 2-month headache diary was obtained, with daily records of headache intensity (0, no headache; 1, mild pain; 2, moderate pain; 3, severe pain) and simultaneous measurements of axillary temperature. Both parameters were registered in the evening, at 6:00 pm every day. The distribution of headache intensity and body temperature as well as the relationship between both variables over time were analyzed with nonparametric tests. RESULTS: The number of days without pain was 28 (45.2%); a mild headache was present on 13 days (21%), a moderate headache on 15 days (24.2%), and a severe headache on 6 days (9.7%). Headache days were associated with higher body temperature than headache-free days (median values: 37.3°C vs 36.6°C; Mann-Whitney U-test, P < 0.001). Moreover, a positive correlation was found between headache intensity and body temperature (Spearman's rho coefficient: 0.83, P < 0.001). CONCLUSIONS: Recurrent increase in body temperature may be another manifestation of the complex clinical spectrum of migraine. This symptom is probably related to hypothalamic involvement.

Epicrania fugax: 19 cases of an emerging headache.

OBJECTIVE: Epicrania fugax (EF) is a primary headache of recent description. We aimed to report 19 new cases of EF, and thus contribute to the characterization of this emerging headache. BACKGROUND: EF is characterized by painful paroxysms starting in a particular area of the head, and rapidly radiating forwards or backwards through the territories of different nerves. The pain is felt in quick motion along a lineal or zigzag trajectory. To date, 47 cases have been published, 34 with forward EF and 13 with backward EF. METHODS: We performed a descriptive study of all EF cases attending our Headache Unit from April 2010 to December 2012. Demographic and clinical data were recorded with a structured questionnaire. RESULTS: Overall, there were 12 women and 7 men. Mean age at onset was 51.7 ± 16.2. Fourteen patients had forward EF, while 5 patients had backward EF. Painful paroxysms lasted 1-4 seconds. Pain intensity was usually moderate or severe, and pain quality was mostly electric. Four patients had ocular autonomic accompaniments. Pain frequency was extremely variable, and 7 patients identified some triggers. Between attacks, 13 patients had some pain or tenderness in the stemming area. Thirteen patients required therapy for their pain. Neuromodulators, indomethacin, anesthetic blockades, and steroid injections were used in different cases, with partial or complete response. CONCLUSION: EF appears as a distinct headache syndrome and could be eventually included in future editions of the International Classification of Headache Disorders.

Wallenberg's syndrome and symptomatic trigeminal neuralgia.

Symptomatic trigeminal neuralgia due to a brainstem infarction is said to be rare. However, facial pain is not uncommon in Wallenberg's syndrome. Facial pain related to a Wallenberg's syndrome may be either persistent of intermittent, and occasionally occurs in brief attacks. Here, we report a patient with a right lateral medullary infarction who started having first division trigeminal neuralgia 1 month after the stroke. The pain paroxysms were suppressed with gabapentin.