3. Immunofluorescence characterization of skin nerve misfolded α-synuclein in different synucleinopathies: A confocal study

Clinical Neurophysiology 128 (2017) e415–e437

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Society Proceedings

Abstracts of the 62nd National Congress of the Italian Society for Clinical Neurophysiology, Ferrara, 21–24 June 2017 Rocco Liguori SINC, Administrative Secretariat, c/o PTS, Via Nizza 45, Roma, 00198, Italy

1. Laser evoked potential in clinical practice: The diagnostic field in small fiber neuropathy—G. Devigili, S. Rinaldo, C. Lettieri, R. Eleopra (Udine, Italy) Small fiber neuropathy (SFN) is frequently encountered in clinical practice. Due to the small nerve fiber characteristics, the diagnosis requires the use of not conventional tests like skin biopsy, Quantitative sensory testing (QST) and Laser Evoked Potentials (LEPs). The aim of this study was to evaluate the diagnostic value of A-delta LEPs in clinical practice in a large cohort of patients with diagnosis of ‘‘definite” SFN. We screened 296 patients evaluated in our institution with confirmed diagnosis of sensory neuropathy. We collected 140 patients with pure SFN and 79 patients with mixed fiber neuropathy (MFN). All underwent clinical evaluation, sensory, painful thermal and mechanical detection thresholds, and quantification of somatic intraepidermal nerve fibers (IENF) by skin biopsy to define the diagnosis. Then, all SFN and MFN patients underwent LEPs. The sensitivity and specificity were calculated compared with our normative data on 67 healthy age-matched subjects. A-delta LEPs at dorsal foot showed 76% sensitivity and 80% specificity in SFN diagnosis, and, if performed bilaterally, the sensitivity and specificity increased (81% and 84%). We did not find any correlation between LEPs and entity of skin denervation, but we found good concordance with warm, heat pain thresholds and pinprick perception. doi:10.1016/j.clinph.2017.09.008

2. Pain catastrophizing and features of cortical response to painful stimuli in fibromyalgia—K. Ricci, E. Vecchio, M. Delussi, A. Montemurno, E. Gentile, M. de Tommaso (Bari, Italy) Gamma Band Oscillations (GBO) after laser stimuli are currently considered a correlate of subjective pain perception. Habituation of laser evoked potentials (LEPs) is reduced in patients with central amplification of pain stimuli. To correlate LEPs habituation and GBO induced by laser stimulation with subjective pain rating and pain catastrophizing in patients with Fibromyalgia (FM) and controls. We recorded LEPs in 30 FM patients and 15 healthy controls by stimulating the dorsum of the right hand. At the end of each series, the perceived pain was rated on a visual pain analogue scale (VAS).

All subjects were submitted to the Pain Catastrophizing Scale – Italian version (PCS-I). The FM patients showed reduced LEPs habituation and increased laser-related GBO. Both patterns correlated with the PCS-I, but not with subjective pain rating. LEPs habituation and GBO may be the expression of cortical mechanisms of nociceptive stimuli processing and exaggerated attentional orientation toward pain experiences. doi:10.1016/j.clinph.2017.09.009

3. Immunofluorescence characterization of skin nerve misfolded in different synucleinopathies: A confocal study—V. Donadio, A. Incensi, O. El-Agnaf, G. Rizzo, N. Vaikath, C. Scaglione, S. Capellari, M. Stanzani Maserati, R. Pantieri, R. Liguori (Bologna, Doha, Qatar)

a-synuclein

Intraneural misfolded a-synuclein (syn) characterized different synucleinopathies such as pure autonomic failure (PAF), idiopathic Parkinson disease (IPD) and dementia with Lewy Bodies (DLB). The aim of this study is to characterize by immunofluorescence the skin intraneural a-synuclein (syn) deposits in PAF, IPD and DLB to ascertain conformation-specific differences which may justify a different clinical phenotype. We identified a total of 21 skin intraneural abnormal syn deposits in PAF (3 patients), 22 in IPD (8 patients) and 40 in DLB (7 patients). Ten healthy subjects were used controls. Skin biopsy was performed on proximal (C7 paravertebral) and distal (thigh and leg) sites. To characterize abnormal syn deposits we used primary antibodies against native a-synuclein (NAC) and against C-terminal asynuclein epitopes involved in post-translational modifications such as phosphorylation at serine 129 (pS129) and tyrosine 125 (pY125), nitrate a-synuclein at tyr125-133 (nY125-133) and advanced glycation end products (AGEs). Furthermore, the mature amyloid asynuclein fibrils were characterized by using a non-commercial antibody (Syn-F) and ubiquitin deposits were identified by a specific antibody (UBI). Antibody raised against pS129 disclosed abnormal skin nerves syn deposits in all patients and never in the control group. Abnormal pS129 syn deposits were often (80–90% of all analysed deposits) stained by the antibody recognizing a fibril conformation, seldom (around 40%) by native antibodies and very occasionally by

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antibodies against nY125-133. Furthermore, abnormal syn deposits were not stained by antibodies against pY125, AGEs and UBI. The immunofluorescence characterization of abnormal syn deposits showed similar findings in IPD, PAF and DLB although in these latter abnormal deposits were quantitatively higher than in IPD. Phosphorylation at serine 129 was the most sensitive and specific epitope to identify skin nerves abnormal syn deposits for the in vivo diagnosis of synucleinopathies; (2) skin syn neuritis showed no relevant immunofluorescence differences in PAF, IPD and DLB suggesting a similar conformation among different clinical phenotypes. doi:10.1016/j.clinph.2017.09.010

4. Does small fiber pathology in PD change over time?— M. Nolano, V. Provitera, A. Stancanelli, A. Saltalamacchia, G. Caporaso, F. Lullo, I. Borreca, G. Piscosquito, B. Lanzillo, L. Santoro (Telese Terme, Italy, Napoli, Italy) Small fiber pathology is part of the clinical picture of PD. Crosssectional studies have shown no correlation between intraepidermal nerve fiber (IENF) density and patient disease duration and severity. However, it is not known whether IENF density changes over time. We aimed to assess the progression of small fiber pathology in PD patients along the disease course. We assessed epidermal innervation at time 0 and after 1–9 years (mean 3.5) in 17 PD patients (M/F = 11/6, age = 64.4 ± 15.3) leg on punch biopsies. Patients were assessed in a rehabilitative setting. They underwent yearly 30-days hospitalizations and were trained to continue a home-personalized program of physical exercises between successive evaluations. Quantitative sensory testing and sudomotor assessment were also performed. Overall, no difference (p = 0.12) between the first and the last IENF density (8.7 ± 4.0 vs. 10.3 ± 4.9) assessment was found. However, the IENF density variation correlated with the disease duration (r = 0.71; p < 0.01). In fact, while in patients with shorter disease duration IENF density increased over time, in patients with longer disease duration (approximately over 8 years) an IENF loss was observed. The small fiber pathology associated to PD can improve to some extent by optimizing patient care, at least in the first stages of disease. doi:10.1016/j.clinph.2017.09.011

5. Vocal cord paralysis in children: A new neurophysiological approach for diagnosis and functional prognosis—P. Lanteri, S. Martelli, F. Bollati, L. Pisciotta, M. Tumulo, R. D’Agostino (Genova, Italy) To establish the possibility to use the methodology of recording corticobulbar motor evoked potentials (CoMEPs) from cricothyroid muscles (CTHY) and vocal cord elicited by transcranial electrical stimulation (TES), as diagnostic tool for predicting function recovery in children with vocal fold immobility (VFI). We included six children (mean age: 4.7 years; range: 2–9 years) with diagnosis of cord immobility that underwent video-fibroendoscopy procedure. Under general anaesthesia, we used TES by stimulation over C3/Cz or C4/Cz to elicit CoMEPs. To record CoMEPs from vocal muscles we used two hook wire electrodes (76 micron diameter) passing through a 27-gauge needle endotracheally placed in the vocal muscles after intubation. Recording of CoMEPs in the vocal muscles after TES was successfully performed bilaterally in 4 patients and monolaterally in two patients. TES over the right or left hemisphere elicited responses

bilaterally. The mean onset latency for the vocal muscles was 16.4 ± 3 ms. The possibility to record CoMEP from vocal muscle was a positive prognostic feature for clinical improvement. This method shows the ability to evaluate the functional integrity of corticobulbar pathways in a reliable manner and adds an additional tool in the diagnosis and prognosis of VFI. doi:10.1016/j.clinph.2017.09.012

6. Trigeminal neuralgia typical and atypical. A disease or two?— C.M. Leone, G. Di Stefano, G. Cruccu, A. Truini (Roma, Italy) Trigeminal Neuralgia (TN) is a clinical condition characterized by a sudden, usually unilateral, brief, stabbing, recurrent pain with a distribution consistent with one or more divisions of the fifth cranial nerve. In the classical form, the genesis of paroxysmal pain has been attributed to areas of focal demyelination due to vascular compression on the nerve. The 20–50% of patients with TN have an atypical form characterized by the presence of constant pain, often described as burning continuous or sub-continuous, as well as paroxysmal pain. We hypothesize an axonal damage underlying the constant pain component. We enrolled 55 patients with typical (n = 36) and atypical (n = 19) TN according to the criteria of the 3rd edition of the International Classification of Headache Disorders (ICHD-3). Each patient underwent magnetic resonance imaging (MRI), laser evoked potentials (LEPs) and trigeminal reflexes. The comparison between the duration of disease between the two groups showed no significant differences. We found a greater asymmetry of amplitude (healthy side vs affected side) of N2-P2 component from thermal stimulation in the group with atypical TN (p < 0.047). The atypical form has an axonal damage and is not a time-bound phenomenon. The involvement of C-fibers could be the mechanism behind continuous pain. doi:10.1016/j.clinph.2017.09.013

7. Cathodal transcranial direct current stimulation reduces seizure frequency and modulates brain functional connectivity with drug-resistant temporal lobe epilepsy: A sham controlled study— G. Assenza, C. Cottone, F. Tecchio, G. Pellegrino, C. Campana, C. Porcaro, A. Cancelli, F. Assenza, G. Di Pino, M. Tombini, V. Di Lazzaro (Roma, Italy, Venezia, Italy, Milano, Italy) Cathodal transcranial direct current stimulation (ctDCS) is a technique able to non-invasively inhibit cortical excitability, which is abnormally increased in epilepsy, but its efficacy in reducing seizures and in modulating epileptic network is still under debate. We evaluated the efficacy of 20-min 1 mA ctDCS vs sham-tDCS in reducing seizure frequency and in modulating the functional connectivity (FC) between epileptic focus (EF) and the other cortical areas, in 10 temporal drug-resistant epilepsy (DRE) patients. After 7 days of seizure diary, patients were randomized to either first-ctDCS or first-sham-ctDCS treatment. On day 8, patients underwent the assigned stimulation. On day 38, patients underwent the opposite stimulation. ctDCS cathode was placed over the EF with a symmetric montage. Immediately before and after stimulations, one-hour video-EEG recording was acquired. ctDCS reduced the percent weekly SF more than sham stimulation. EA changes did not differ between ctDCS respect to shamctDCS. FC changed after real stimulation in all patients and involved