Association of Obstructive Sleep Apnea and Atrial Fibrillation in Acute Ischemic Stroke: A Cross-Sectional Study.

Background: There is a growing body of evidence suggesting a link between obstructive sleep apnea (OSA) and atrial fibrillation (AF). The primary objective of this study is to evaluate the association between OSA and AF in acute ischemic stroke. The secondary objective is to describe the clinical features of patients with acute ischemic stroke and concomitant OSA. Methods: We enrolled consecutive patients with acute ischemic stroke. All patients underwent full-night cardiorespiratory polygraphy. To determine if there is an association between AF and OSA, we compared the observed frequency of this association with the expected frequency from a random co-occurrence of the two conditions. Subsequently, patients with and without OSA were compared. Results: A total of 174 patients were enrolled (mean age 67.3 ± 11.6 years; 95 males). OSA and AF were present in 89 and 55 patients, respectively. The association OSA + AF was observed in 33/174 cases, which was not statistically different compared to the expected co-occurrence of the two conditions. Patients with OSA showed a higher neck circumference and body mass index, a higher prevalence of hypertension and dysphagia, and a higher number of central apneas/hypoapneas. In the multivariate analysis, dysphagia and hypertension were independent predictors of OSA. A positive correlation was observed between OSA severity, BMI, and neck circumference. The number of central apneas/hypoapneas was positively correlated with stroke severity. Conclusions: Our data suggest that OSA and AF are highly prevalent but not associated in acute stroke. Our findings support the hypothesis that OSA acts as an independent risk factor for stroke.

Suitability of electroencephalography in brain death determination: a monocentric, 10-year retrospective, observational investigation of 428 cases.

BACKGROUND: We aimed to verify the usefulness of electroencephalographic (EEG) activity recording (that is mandatory according to the Italian law), in addition to two clinical evaluations spaced 6 h, among the procedures of brain death determination (BDD) in adult individuals. METHODS: The study is a monocentric, retrospective analysis of all BDDs performed in the last 10 years at Policlinico Le Scotte in Siena (Italy). RESULTS: Of the 428 cases revised (mean age 67.6 ± 15.03 years; range 24-92 years), 225 were males and 203 females. In total, 212 out of 428 patients (49.5%) were donors. None of the BDD procedures were interrupted due to the reappearance of EEG activity (neither for clinical reasons) at any sampling time, with the exception of one case that was considered a false negative at critical reinspection of the EEG. In 6/428 cases (1.4%), a cardiac arrest occurred during the 6 h between the first and second evaluation, thus missing the opportunity to take organs from these patients because the BDD procedure was not completed. CONCLUSIONS: Once the initial clinical examination before convening the BDD Commission has ascertained the absence of brainstem reflexes and of spontaneous breathing, and these clinical findings are supported by a flat EEG recording, the repetition of a 30-min EEG twice over a 6 h period seems not to add additional useful information to clinical findings. Current data, if confirmed in other centers and possibly in prospective studies, may help to promote a scientific and bioethical debate in Italy, as well as in other countries where the EEG is still mandatory, for eventually updating the procedures of BDD.

Homotopic reduction in laser-evoked potential amplitude and laser-pain rating by abdominal acupuncture.

BACKGROUND: The neural mechanism underlying the analgesic effect of acupuncture is largely unknown. We aimed at investigating the effect of abdominal acupuncture (AA) on the laser-evoked potential (LEP) amplitude and laser-pain rating to stimulation of body parts either homotopic or heterotopic to the treated acupoint. METHODS: Laser-evoked potentials were recorded from 13 healthy subjects to stimulation of the right wrist (RW), left wrist (LW) and right foot (RF). LEPs were obtained before, during and after the AA stimulation of an abdominal area corresponding to the representation of the RW. Subjective laser-pain rating was collected after each LEP recording. RESULTS: The amplitude of the N2/P2 LEP component was significantly reduced during AA and 15 min after needle removal to both RW (F = 4.14, p = .02) and LW (F = 5.48, p = .008) stimulation, while the N2/P2 amplitude to RF stimulation (F = 0.94, p = .4) remained unchanged. Laser-pain rating was reduced during AA and 15 min after needle removal only to RW stimulation (F = 5.67, p = .007). CONCLUSION: Our findings showing an AA effect on LEP components to both the ipsilateral and contralateral region homotopic to the treated area, without any LEP change to stimulation of a heterotopic region, suggest that the AA analgesia is mediated by a segmental spinal mechanism. SIGNIFICANCE: Although abdominal acupuncture has demonstrated to be effective in the reduction in laser-evoked potential (LEP) amplitude and laser-pain rating, the exact mechanism of this analgesic effect is not known. In the current study, we found that treatment of an area in the "turtle representation" of the body led to a topographical pattern of LEP amplitude inhibition that can be mediated by a segmental spinal mechanism.

Polysomnographic and psychometric correlates of napping in primary insomnia patients.

Introduction: This study aims to evaluate napping in patients with insomnia compared with two control groups and to investigate the relationships between psychometric measures and napping habitude.Methods: Sixty-eight adult patients with chronic primary insomnia were enrolled; 27 men and 41 women, mean age 53.6 ± 13. All patients underwent 24 h ambulatory polysomnography (A-PSG). Prevalence of napping behavior in Insomnia Patients (I-group) was compared with Obstructive Sleep Apnea Syndrome (OSAS) patients (OSAS-group) and epilepsy patients (Ep-group). Patients were evaluated with Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS) and Berlin Questionnaire. Psychometric evaluation included Self-Administered Anxiety Scale (SAS #54), Beck Depression Inventory (BDI), Maudsley's Obsessive Compulsive Inventory (MOCI), Snaith-Hamilton Pleasure Scale (SHAPS), and Eating Attitude Test (EAT-26).Results: No significant differences resulted in prevalence and duration of naps in the three groups. In the comparison between nappers (N+, subject with at least one nap in A-PSG) and non-nappers (N-, subject with no naps in A-PSG) we observed significant differences in PSQI scores (N+ = 14.1 ± 2.7; N- =11.9 ± 3.3; Whitney U-test = 341.0; p = 0.004) and in EAT score (N+ = 9.8 ± 9.7; N- = 4.4 ± 5.6; Whitney U-test = 313.5, p = 0.0.14); no significant differences were measured in other psychometric parameters and in sleep macrostructural indexes.Conclusions: Our data are in accordance with previous findings outlining that N + insomniacs have higher PSQI scores than N-. Our results do not confirm the suggested association between napping and depressive or obsessive-compulsive symptoms. Conversely, we found a statistically significant difference (p = 0.0014) in EAT scores in N + and N-. Hyperarousal and REM sleep instability in insomniac patients may create an unbalance of the neuroendocrine hypothalamic regulation leading to an appetite alteration.

Usefulness of psychoeducational intervention in chronic insomnia: an actigraphic study.

Background: Chronic Insomnia is a severe and disabling condition characterized by difficulty in initiating or maintaining sleep, waking up too early, despite adequate opportunity and circumstances for sleep. Maladaptive thoughts and dysfunctional beliefs about sleep are considered crucial factors in developing and perpetuating this disorder.Aims: The aim of the study was to explore the usefulness, in patients with chronic insomnia, of a one-session psychoeducational intervention on sleep-related maladaptive thoughts and beliefs, and on sleep perception.Methods: Thirty-eight patients with chronic insomnia were enrolled in the study and randomly assigned to receive psychoeducational intervention (PI+) or to act as controls (PI-). Patients wore an actigraph and compiled a sleep diary for 14 d. After the first 7 d, only PI+ patients received one session of psychoeducational intervention.Results: A significant reduction of sleep related preoccupations, a reduction of dysfunctional beliefs about sleep, and an improvement of subjective perception of sleep were observed in the PI+ group, but not in the PI- group. No significant modification was observed for objective total sleep time.Conclusions: Our results suggest that one-session psychoeducational intervention is associated with a decrease of sleep-related maladaptive thoughts and beliefs, and with an improvement on subjective sleep perception.

Abnormal Circadian Modification of Aδ-Fiber Pathway Excitability in Idiopathic Restless Legs Syndrome.

Restless legs syndrome (RLS) is characterized by unpleasant sensations generally localized to legs, associated with an urge to move. A likely pathogenetic mechanism is a central dopaminergic dysfunction. The exact role of pain system is unclear. The purpose of the study was to investigate the nociceptive pathways in idiopathic RLS patients. We enrolled 11 patients (mean age 53.2 ± 19.7 years; 7 men) suffering from severe, primary RLS. We recorded scalp laser-evoked potentials (LEPs) to stimulation of different sites (hands and feet) and during two different time conditions (daytime and nighttime). Finally, we compared the results with a matched control group of healthy subjects. The Aδ responses obtained from patients did not differ from those recorded from control subjects. However, the N1 and the N2-P2 amplitudes' night/day ratios after foot stimulation were increased in patients, as compared to controls (N1: patients: 133.91 ± 50.42%; controls: 83.74 ± 34.45%; p = 0.016; Aδ-N2-P2: patients: 119.15 ± 15.56%; controls: 88.42 ± 23.41%; p = 0.003). These results suggest that RLS patients present circadian modifications in the pain system, which are not present in healthy controls. Both sensory-discriminative and affective-emotional components of pain experience show parallel changes. This study confirms the structural integrity of Aδ nociceptive system in idiopathic RLS, but it also suggests that RLS patients present circadian modifications in the pain system. These findings could potentially help clinicians and contribute to identify new therapeutic approaches.

Autonomic Nervous System Modifications During Wakefulness and Sleep in a Cohort of Patients with Acute Ischemic Stroke.

GOAL: The aims of our study were to investigate autonomic modifications in wakefulness and sleep in a cohort of patients with acute ischemic stroke and to evaluate whereas these modifications were dependent by sleep stage and stroke lateralization. MATERIALS AND METHODS: We prospectively enrolled 42 patients (22 men and 20 women, mean age: 69.8 ± 11.3; range: 32-92 years) with acute ischemic stroke. All participants underwent a full-night polysomnography. As index of autonomic nervous system we used Heart Rate Variability (HRV), analyzed in wakefulness and during different sleep stages. First, we compared our cohort with a control group of 42 healthy subjects, matched for age and sex. Subsequently, we divided our cohort in 2 subgroups according stroke lateralization (21 right, 21 left) and compared with control population. FINDINGS: We observed significant modifications of HRV parameters mainly for the right lesions. In particular, we observed a prevalent parasympathetic tone during the wake (low frequency/high frequency [LF/HF]: right: 2.99 ± 8.91; controls: 3.88 ± 3.42; P < .01) and during REM (LF/HF right: 0.03 ± 1.58; controls: 2.92 ± 3.97; P < .01) accompanied by a significant reduction of sympathetic tone during REM (LF right: 23.85 ± 44.42 n.u.; controls: 51.13 ± 32.25 n.u.; P < .01), and by a reduction of parasympathetic tone during N3 (HF right: 28.09 ± 37.67 n.u.; controls: 43.08 ± 68.39 n.u.; P < .01). CONCLUSIONS: Our study indicates that autonomic dysfunctions in acute ischemic stroke are prevalent in right-side lesions and strictly dependent by sleep-wake stage.

Low-Frequency rTMS of the Primary Motor Area Does Not Modify the Response of the Cerebral Cortex to Phasic Nociceptive Stimuli.

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive technique of cortical stimulation. Although the exact mechanism of action is not clearly understood, it has been postulated that rTMS action on pain depends most on stimulation sites and stimulation parameters. Most studies concern high-frequency rTMS of the primary motor cortex (M1). High-frequency rTMS over motor cortex seems to induce an analgesic effect while contrasting results were reported after low-frequency rTMS. The aim of the current study was to investigate the effects of 1 Hz rTMS stimulation over the left primary motor cortex on subjective laser pain rating and laser evoked potential (LEP) amplitudes in healthy subjects. Subjects underwent two different sessions (real and sham rTMS) according to a cross-sectional design. In each session, LEPs and laser-pain rating to stimulation of both right and left hand dorsum were collected before 1 Hz rTMS over the left M1 area (baseline), which lasted 20 min. Then, LEPs and laser-pain rating were measured immediately after rTMS (T0), after 20 min from T0 (T0+20), and after 40 min from T0 (T0+40). We could not find any modification of both laser-pain rating and LEP parameters (latencies and amplitudes) following 1 Hz rTMS. Therefore, our results show that the low-frequency rTMS of the M1 area does not change the response of the cerebral cortex to pain.

Dysphagia and Obstructive Sleep Apnea in Acute, First-Ever, Ischemic Stroke.

BACKGROUND: Obstructive sleep apnea (OSA) and dysphagia are common in acute stroke and are both associated with increased risk of complications and worse prognosis. The aims of the present study were (1) to evaluate the prevalence of OSA and dysphagia in patients with acute, first-ever, ischemic stroke; (2) to investigate their clinical correlates; and (3) to verify if these conditions are associated in acute ischemic stroke. METHODS: We enrolled a cohort of 140 consecutive patients with acute-onset (<48 hours), first-ever ischemic stroke. Computed tomography (CT) and magnetic resonance imaging scans confirmed the diagnosis. Neurological deficit was measured using the National Institutes of Health Stroke Scale (NIHSS) by examiners trained and certified in the use of this scale. Patients underwent a clinical evaluation of dysphagia (Gugging Swallowing Screen) and a cardiorespiratory sleep study to evaluate the presence of OSA. RESULTS: There are 72 patients (51.4%) with obstructive sleep apnea (OSA+), and there are 81 patients (57.8%) with dysphagia (Dys+). OSA+ patients were significantly older (P = .046) and had greater body mass index (BMI) (P = .002), neck circumference (P = .001), presence of diabetes (P = .013), and hypertension (P < .001). Dys+ patients had greater NIHSS (P < .001), lower Alberta Stroke Programme Early CT Score (P < .001), with greater BMI (P = .030). The association of OSA and dysphagia was greater than that expected based on the prevalence of each condition in acute stroke (P < .001). CONCLUSIONS: OSA and dysphagia are associated in first-ever, acute ischemic stroke.

Focal Mechanical Vibration Does not Change Laser-Pain Perception and Laser-Evoked Potentials: A Pilot Study.

BACKGROUND: Nonpainful tactile and electrical stimulation of the large myelinated fibers reduces spontaneous pain and the amplitude of laser-evoked potentials (LEPs), which represent the most reliable technique to assess the nociceptive pathway function. Focal mechanical vibration stimulates the Aß afferents selectively; thus, it is conceivable its action on nociceptive pathways. AIM: The aim of this study was to investigate the effect of vibratory stimuli, activating either both muscle and skin receptors or cutaneous afferents only on the LEPs and subjective laser-pain rating. METHODS: Ten healthy volunteers were studied. The subjects were evaluated in two different sessions to test muscle and skin receptors or cutaneous afferents only. In each session, LEPs were recorded to stimulation of the dorsal hand skin in radial and ulnar territory bilaterally, while the vibratory stimulus was delivered on the radial territory of the right forearm. RESULTS: The results showed a substantial stability of the potential N1 and N2/P2 after the two protocols, with a declining trend from the initial to the last test of the same session, probably due to habituation. Accordingly, the laser-pain perception did not change during the experimental setting. CONCLUSIONS: We conclude that a vibratory stimulus is ineffective in reducing the laser-evoked potentials and laser-pain perception.

Hyperventilation in Patients With Focal Epilepsy: Electromagnetic Tomography, Functional Connectivity and Graph Theory - A Possible Tool in Epilepsy Diagnosis?

PURPOSE: Hyperventilation (HV) is a commonly used electroencephalogram activation method. METHODS: We analyzed EEG recordings in 22 normal subjects and 22 patients with focal epilepsy of unknown cause. We selected segments before (PRE), during (HYPER), and 5 minutes after (POST) HV. To analyze the neural generators of EEG signal, we used standard low-resolution electromagnetic tomography (sLORETA software). We then computed EEG lagged coherence, an index of functional connectivity, between 19 regions of interest. A weighted graph was built for each band in every subject, and characteristic path length (L) and clustering coefficient (C) have been computed. Statistical comparisons were performed by means of analysis of variance (Group X Condition X Band) for mean lagged coherence, L and C. RESULTS: Hyperventilation significantly increases EEG neural generators (P < 0.001); the effect is particularly evident in cingulate cortex. Functional connectivity was increased by HV in delta, theta, alpha, and beta bands in the Epileptic group (P < 0.01) and only in theta band in Control group. Intergroup analysis of mean lagged coherence, C and L, showed significant differences for Group (P < 0.001), Condition (P < 0.001), and Band (P < 0.001). Analysis of variance for L also showed significant interactions: Group X Condition (P = 0.003) and Group X Band (P < 0.001). CONCLUSIONS: In our relatively small group of epileptic patients, HV is associated with activation of cingulate cortex; moreover, it modifies brain connectivity. The significant differences in mean lagged coherence, path length, and clustering coefficient permit to hypothesize that this activation method leads to different brain connectivity patterns in patients with epilepsy when compared with normal subjects. If confirmed by other studies involving larger populations, this analysis could become a diagnostic tool in epilepsy.

Sleep and fatigue in multiple sclerosis: A questionnaire-based, cross-sectional, cohort study.

INTRODUCTION: Fatigue and sleep disorders are frequently reported in patients affected by Multiple Sclerosis (MS) but the causes and the relationship are not yet fully understood. This study aimed at evaluating their prevalence, at determining the relationships between clinical findings of MS and the occurrence of sleep disorders and at investigating the relations between sleep disorders and fatigue. METHODS: One hundred and two MS patients were enrolled in the study. They were analyzed on both their clinical features (type of MS, disease duration, clinical severity, type of treatment, presence of spinal demyelinating lesions) and specific scales scores (Expanded Disability Status Scale, Modified Fatigue Impact Scale - MFIS, Self-Administered Anxiety Scale - SAS, Beck's Depression Inventory - BDI, Pittsburgh Sleep Quality Index - PSQI, Epworth Sleepiness Scale - ESS, and the Berlin's questionnaire for Obstruction Sleep Apnea Syndrome - OSAS). RESULTS: Patients with poor sleep quality are more frequently fatigued (p=0.001), have higher MFIS global scores (p<0.001), higher prevalence of RLS symptoms (p=0.049), and show higher scores at BDI (p=0.017) and SAS (p≤0.001). Conversely patients with fatigue show older age (p=0.005), higher prevalence of sleepiness (p=0.021), higher prevalence of RLS symptoms (p=0.030), higher prevalence of poor sleep quality (p<0.001) with higher PSQI scores (p<0.001), higher scores on the BDI (p<0.001) and SAS (p≤0.001). CONCLUSION: This study shows that MS is associated with a high prevalence of sleep complaints, including subjectively poor sleep quality, excessive daytime sleepiness, RLS and symptoms of OSAS. Further, it demonstrated a strict relation between fatigue and sleep disorders. Finally, it underlines their relationship with anxiety and depression in MS patients.

Expectation to feel more pain disrupts the habituation of laser-pain rating and laser-evoked potential amplitudes.

Increased pain perception due to the expectation to feel more pain is called nocebo effect. The present study aimed at investigating whether: (1) the mere expectation to feel more pain after the administration of an inert drug can affect the laser-pain rating and the laser-evoked potential (LEP) amplitude, and (2) the learning potentiates the nocebo effect. Eighteen healthy volunteers were told that an inert cream, applied on the right hand, would increase the laser pain and LEP amplitude to right hand stimulation. They were randomly assigned to either "verbal session" or "conditioning session". In the "verbal session", LEPs to both right and left hand stimulation were recorded at the same intensity before (baseline) and after cream application. In the "conditioning session", after an initial cream application the laser stimulus intensity was increased surreptitiously to make the subjects believe that the treatment really increased the pain sensation. Then, the cream was reapplied, and LEPs were recorded at the same stimulus intensity as at the baseline. It was found that the verbal suggestion to feel more pain disrupted the physiological habituation of the laser-pain rating and LEP amplitude to treated (right) hand stimulation. Unlike previously demonstrated for the placebo effect, the learning did not potentiate the nocebo effect.

Regional distribution of ventilation in patients with obstructive sleep apnea: the role of thoracic electrical impedance tomography (EIT) monitoring.

PURPOSE: The aim of our study was to apply the electrical impedance tomography (EIT) technique to the study of ventilation during wake and NREM and REM sleep in patients with obstructive sleep apneas (OSA). METHODS: This is a prospective, observational, monocentric, pilot study in a neurology department with a sleep disorder center. Inclusion criteria were age ≥18 years, both gender, and diagnosis of OSA. Exclusion criteria were the contraindications to the thoracic EIT. All patients underwent laboratory-based polysomnography (PSG) alongside thoracic EIT. Primary endpoint was to compare the global impedance (GI) among the conditions: "Wake" vs "Sleep," "NREM" vs "REM," and "OSA" vs "Non-OSA." Secondary endpoint was to measure the regional distribution of impedance in the four regions of interest (ROIs), in each condition. RESULTS: Of the 17 consecutive patients enrolled, two were excluded because of poor-quality EIT tracings. Fifteen were analyzed, 10 men and 5 women, mean age 51.6 ± 14.4 years. GI was higher in Wake vs Sleep (Wake 13.24 ± 11.23; Sleep 12.56 ± 13.36; p < 0.01), in NREM vs REM (NREM 13.48 ± 13.43; REM 0.59 ± 0.01; p < 0.01), and in Non-OSA vs OSA (Non-OSA 10.50 ± 12.99; OSA 18.98 ± 10.06; p < 0.01). No significant differences were observed in the regional distribution of impedance between Wake and Sleep (χ 2 = 3.66; p = 0.299) and between Non-OSA and OSA (χ 2 = 1.00; p = 0.799); conversely, a significant difference was observed between NREM and REM sleep (χ 2 = 62.94; p < 0.001). CONCLUSIONS: To our knowledge, this is the first study that addresses the issue of regional ventilation in OSA patients during sleep. Thoracic electrical impedance changes through the sleep-wake cycle and during obstructive events. The application of thoracic EIT can prove a valuable additional strategy for the evaluation of OSA patients.

Post-Encephalitic Parkinsonism and Sleep Disorder Responsive to Immunological Treatment: A Case Report.

We describe a 70-year-old man who, after a viral encephalitis associated with pneumonia, progressively developed a parkinsonism associated with lethargy. Encephalitis manifested with persistent hiccups, seizures and impairment of consciousness. After 2 weeks, the initial neurologic symptoms subsided and the patient progressively developed movement disorders (rigidity and bradykinesia, resistant to L-DOPA), lethargy and behavioral hypersomnia. Magnetic resonance imaging showed thalamic and hippocampal signal abnormalities, immunohistochemistry on a mouse brain substrate revealed serum autoantibodies binding to the brainstem neuropil. Polysomnographic monitoring was consistent with a very severe disruption of sleep: the sleep-wake cycle was fragmented, and the NREM-REM ultradian cycle was irregular. Intravenous immune globulin therapy resulted in the complete reversal of the movement and the sleep disorders. Our observation confirms that parkinsonism and sleep disorders may be consequences of encephalitis, that an immune-mediated pathogenesis is likely, and, consequently, that immunotherapy can be beneficial in these patients. The polysomnographic monitoring suggests that lethargia, rather than a mere hypersomnia, is the result of a combination between sleep disruption and altered motor control.

Warmth and nociceptive evoked potentials in cold-induced sweating syndrome type 1.

INTRODUCTION: Cold-induced sweating syndrome type 1 (CISS1), is a rare, severe, autosomal recessive disease. It is characterized by morphological alterations and profuse sweating when ambient temperature is <22 °C. Although some individuals with CISS1 have decreased pain perception, no study has been conducted to evaluate thermal and pain sensations in these patients. The aim of this study was to assess the function of the nociceptive Aδ-fibers and warmth C-fibers by using CO2 laser-evoked potentials (LEPs) in patients affected by CISS1. METHODS: Four patients were studied. Laser pulses were applied to the skin of the right hand and the perioral region at painful intensity to record Aδ-LEPs, and at non-painful intensity to obtain C-LEPs. Fifteen healthy subjects were studied for control purposes. RESULTS: No significant difference in latencies or amplitudes of either Aδ- or C-LEPs was found between the 2 groups. CONCLUSION: Cutaneous nociceptive and warmth pathway functions are normal in CISS1. Muscle Nerve 54: 100-103, 2016.

Cortical inhibition of laser pain and laser-evoked potentials by non-nociceptive somatosensory input.

Although the inhibitory action that tactile stimuli can have on pain is well documented, the precise timing of the interaction between the painful and non-painful stimuli in the central nervous system is unclear. The aim of this study was to investigate this issue by measuring the timing of the amplitude modulation of laser evoked potentials (LEPs) due to conditioning non-painful stimuli. LEPs were recorded from 31 scalp electrodes in 10 healthy subjects after painful stimulation of the right arm (C6-C7 dermatomes). Non-painful electrical stimuli were applied by ring electrodes on the second and third finger of the right hand. Electrical stimuli were delivered at +50, +150, +200 and +250 ms interstimulus intervals (ISIs) after the laser pulses. LEPs obtained without any conditioning stimulation were used as a baseline. As compared to the baseline, non-painful electrical stimulation reduced the amplitude of the vertex N2/P2 LEP component and the laser pain rating when electrical stimuli followed the laser pulses only at +150 and +200 ms ISIs. As at these ISIs the collision between the non-painful and painful input is likely to take place at the cortical level, we can conclude that the late processing of painful (thermal) stimuli is partially inhibited by the processing of non-painful (cutaneous) stimuli within the cerebral cortex. Moreover, our results do not provide evidence that non-painful inputs can inhibit pain at a lower level, including the spinal cord.

Neurophysiological correlates of eye movement desensitization and reprocessing sessions: preliminary evidence for traumatic memories integration.

We have investigated the potential role of eye movement desensitization and reprocessing (EMDR) in enhancing the integration of traumatic memories by measuring EEG coherence, power spectra and autonomic variables before (pre-EMDR) and after (post-EMDR) EMDR sessions during the recall of patient's traumatic memory. Thirteen EMDR sessions of six patients with post-traumatic stress disorder were recorded. EEG analyses were conducted by means of the standardized Low Resolution Electric Tomography (sLORETA) software. Power spectra, EEG coherence and heart rate variability (HRV) were compared between pre- and post-EMDR sessions. After EMDR, we observed a significant increase of alpha power in the left inferior temporal gyrus (T = 3.879; P = 0.041) and an increased EEG coherence in beta band between C3 and T5 electrodes (T = 6.358; P < 0.001). Furthermore, a significant increase of HRV in the post-EMDR sessions was also observed (pre-EMDR: 6.38 ± 6.83; post-EMDR: 2.46 ± 2.95; U-Test = 45, P = 0.043). Finally, the values of lagged coherence were negatively associated with subjective units of disturbance (r(24) = -0.44, P < 0.05) and positively associated with parasympathetic activity (r(24) = 0.40, P < 0.05). Our results suggest that EMDR leads to an integration of dissociated aspects of traumatic memories and, consequently, a decrease of hyperarousal symptoms [Correction made here after initial publication].