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This article provides recommendations on the minimum standards for recording routine ("standard") and sleep electroencephalography (EEG). The joint working group of the International Federation of Clinical Neurophysiology (IFCN) and the International League Against Epilepsy (ILAE) developed the standards according to the methodology suggested for epilepsy‐related clinical practice guidelines by the Epilepsy Guidelines Working Group. We reviewed the published evidence using the Preferred Reporting Items for Systematic Review and Meta‐Analysis (PRISMA) statement. The quality of evidence for sleep induction methods was assessed by the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) method. A tool for Quality Assessment of Diagnostic Studies (QUADAS‐2) was used to assess the risk of bias in technical and methodological studies. Where high‐quality published evidence was lacking, we used modified Delphi technique to reach expert consensus. The GRADE system was used to formulate the recommendations. The quality of evidence was low or moderate. We formulated 16 consensus‐based recommendations for minimum standards for recording routine and sleep EEG. The recommendations comprise the following aspects: indications, technical standards, recording duration, sleep induction, and provocative methods. [ABSTRACT FROM AUTHOR]

Chronic inflammatory demyelinating polyradiculopathy is mainly based on clinical and electrophysiological criteria. If electrophysiological findings remain questionable for the diagnosis of CIDP and/or clinical presentation is atypical, nerve biopsy may assist the diagnosis. We present a case in which the nerve biopsy was helpful in diagnosis of CIDP and revealed the peculiar presence of tomacula. [ABSTRACT FROM AUTHOR]

Quantitative sensory testing (QST) is a potentially useful tool for measuring sensory impairment for clinical and research studies but there is still no consensus regarding the place of this evaluation in every day clinical practice. Our study included 15 patients previously diagnosed with neuropathic pain due to small fiber sensory polyneuropathy based on clinical and electrodiagnostic criteria.Variables were compared with an age matched control group of 7 healthy persons. We looked to pain severity rated on Visual Analog Scale and Pain Detect Questionnaire and we searched for correlations with sensory nerve conduction studies and parameters of quantitative sensory testing - thermotest, limits method. QST was a sensitive technique for evaluation of patients with small fiber sensory polyneuropathy. Score on Pain Detect Questionnaire has statistically significant correlation with values recorded for cooling detection threshold on QST, documenting sensory loss and A delta fibers dysfunction in the study group. [ABSTRACT FROM AUTHOR]

Objective To investigate functional coupling between brain networks using spectral changes induced by single-pulse electric stimulation (SPES). Method We analyzed 20 patients with focal epilepsy, implanted with depth electrodes. SPES was applied to each pair of adjacent contacts, and responses were recorded from all other contacts. The mean response amplitude value was quantified in three time-periods after stimulation (10–60, 60–255, 255–500 ms) for three frequency-ranges (Gamma, Ripples, Fast-Ripples), and compared to baseline. A total of 30,755 responses were analyzed, taking into consideration three dichotomous pairs: stimulating in primary sensory areas (S1-V1) vs. outside them, to test the interaction in physiologic networks; stimulating in seizure onset zone (SOZ) vs. non-SOZ, to test pathologic interactions; recording in default mode network (DMN) vs. non-DMN. Results Overall, we observed an early excitation (10–60 ms) and a delayed inhibition (60–500 ms). More specifically, in the delayed period, stimulation in S1-V1 produced a higher gamma-inhibition in the DMN, while stimulation in the SOZ induced a higher inhibition in the epilepsy-related higher frequencies (Ripples and Fast-Ripples). Conclusion Physiologic and pathologic interactions can be assessed using spectral changes induced by SPES. Significance This is a promising method for connectivity studies in patients with drug-resistant focal epilepsy. [ABSTRACT FROM AUTHOR]

Objective To investigate default-mode network (DMN) deactivation in different types of focal epilepsy by single pulse electric stimulation (SPES). Method We analyzed 18 patients with focal epilepsy (8 frontal, 8 temporal, 2 posterior), implanted with depth electrodes. SPES was applied to each pair of adjacent contacts in seiwure onset zone (SOZ), and responses were recorded from the 10 different DMN-hubs; The responses to SPES in Gamma, Ripple (R) and Fast-Ripple (FR) bands were quantified in a 60–250 ms time-window following each stimulation pulse and compared to baseline. Time of propagation was determined based on N1 latency. These responses were compared across the three epilepsy types. Results Overall, we observed a significant deactivation of the DMN in the upper frequency ranges for all epilepsies (75% drop from baseline for gamma and 93% for R and FR). In the gamma band, the stimulation of frontal SOZs deactivated the ipsilateral posterior cingulate and precuneus significantly more than in the other epilepsy-types, with shorter general latencies of 22, 25 and 23 ms, respectively. Discussion Our results might explain why in prefrontal focal epilepsies and in generalized epilepsies, thought to have a frontal generator, the consciousness is preferentially and significantly impaired. Significance This is a promising method for quantifying the engagement of the consciousness processing areas by the epileptic focus. Detailed illustrations and tables for all 10 DMN-hubs, in all 3 high-frequency bands are provided. [ABSTRACT FROM AUTHOR]