Pablo Brea Winckler

Oppositionality and sympathetic skin response in adolescents: specific associations with the headstrong/hurtful dimension.

Oppositionality encompasses distinct dimensions, and few studies have investigated the validity of such distinctions from a pathophysiological perspective. Our aim was to investigate the association between sympathetic skin responses (SSR) and distinct oppositional dimensions in a community sample of adolescents. Forty adolescents aged 13.84±1.46 years participated in this study. Oppositionality was measured by externalizing behavior and bullying scores (dependent variables), while SSR was recorded by electrical changes at the skin level (independent variables). Results showed that increased SSRs were associated with oppositionality; however, these associations were specific to the headstrong/hurtful dimension. Further exploratory analyses demonstrated that increased SSRs were associated with several types of headstrong/hurtful behaviors and underscore the importance of the first aversive stimuli to differentiate groups with low and high headstrong/hurtful behaviors. There were no differences between groups regarding time until habituation. This study provides insights about how dysfunctions in autonomic balance may contribute to the emergence of oppositional behavior among adolescents.

Simultaneous Median–radial Nerve Electrical Stimulation Revisited: An Accurate Approach to Carpal Tunnel Syndrome Diagnosis and Severity

Purpose: To assess the accuracy of an unusual test for CTS investigation and correlate it with clinical symptoms. Methods: Initially, we applied a visual analog scale for CTS discomfort (CTS-VAS) and performed a standard electrophysiologic test for CTS diagnosis (median–ulnar velocity comparison). Posteriorly, a blinded neurophysiologist performed the orthodromic simultaneous median–radial nerve stimulation (SMRS) at the thumb, with recording of both action potentials over the lateral aspect of the wrist. Results: All hands (106) showed median–radial action potential splitting using the SMRS technique, in which was possible to measure the interpeak latencies (IPLs) between action potentials. The IPL and median nerve conduction velocity were different according to CTS intensity (Bonferroni; P < 0.001). There was significant correlation between IPL and median nerve conduction velocity (Spearman; r = −0.51; P < 0.01). In the same way, there was a significant correlation between IPL and median nerve conduction velocity with CTS-VAS (r = 0.6 and r = −0.3, respectively). The duration and unpleasantness of the SMRS procedure were lower when compared with standard approach (t Student < 0.001 for both comparisons). Twenty-nine symptomatic patients (39 hands) who did not fulfill criteria for CTS based on standard approach showed abnormal IPLs. Conclusions: The SMRS technique is a simple, sensitive, and tolerable approach for CTS diagnosis. Apart from that, the data from SMRS correlated better with clinical impact of CTS in comparison with the standard approach. Therefore, this method might be useful as adjunct to standard electrophysiologic approaches in clinical practice.

Breach effect over mitten patterns mimicking focal spike-waves in a patient with psychogenic nonepileptic seizures.

Psychogenic nonepileptic seizures (PNES) resemble epileptic seizures. Video-EEG is the gold-standard diagnostic tool (Reuber, 2009). About 20% of patients with PNES are misdiagnosed as epileptics (Boesebeck et al., 2010), mainly by EEG overinterpretation (Benbadis and Tatum, 2003). We saw a 48-years-old woman with spells since she was 14, taking three antiepileptic drugs (AEDs), and having three seizures by day on admission. An aneurysm was clipped 2 years before through a left frontotemporal craniotomy. We recorded a videoEEG, with the following technical parameters: time constant, 0.1 s; high-frequency filter, 70 Hz; sensitivity, 10 lV/mm; page size, 10 s. PNES were characterized by a motionless stare during 3 min. On sleep, breach effect over mitten patterns mimicked frontal spike-and-wave complexes (Fig. 1). Normal variants, or benign variants of uncertain significance, are rhythmic or epileptiform patterns are often misinterpreted as an abnormal EEG. They possess some characteristics common to epileptiform patterns, and may reflect pitfalls for those interpreting EEGs (Benbadis and Tatum, 2003). Mitten pattern, one of these normal variants, are a superimposition of a sharp wave on the slope of a slow wave with same polarity, centered in the frontal-central midline. With skull defects, non-epileptogenic activity may be misunderstood as pathologic discharges (Brigo et al., 2011). Breach effect over a mitten pattern is another benign epileptiform variant. Overinterpretation of EEG may cause unnecessary medical (AED side effects) and financial consequences (Privitera, 2011). In this case, a peculiar normal variant influenced by a previous neurosur-