Karlo Faria Nunes

Pudendal somatosensory evoked potentials in normal women

OBJECTIVE Somatosensory evoked potential (SSEP) is an electrophysiological test used to evaluate sensory innervations in peripheral and central neuropathies. Pudendal SSEP has been studied in dysfunctions related to the lower urinary tract and pelvic floor. Although some authors have already described technical details pertaining to the method, the standardization and the influence of physiological variables in normative values have not yet been established, especially for women. The aim of the study was to describe normal values of the pudendal SSEP and to compare technical details with those described by other authors. MATERIALS AND METHODS The clitoral sensory threshold and pudendal SSEP latency was accomplished in 38 normal volunteers. The results obtained from stimulation performed on each side of the clitoris were compared to ages, body mass index (BMI) and number of pregnancies. RESULTS The values of clitoral sensory threshold and P1 latency with clitoral left stimulation were respectively, 3.64 +/- 1.01 mA and 37.68 +/- 2.60 ms. Results obtained with clitoral right stimulation were 3.84 +/- 1.53 mA and 37.42 +/- 3.12 ms, respectively. There were no correlations between clitoral sensory threshold and P1 latency with age, BMI or height of the volunteers. A significant difference was found in P1 latency between nulliparous women and volunteers who had been previously submitted to cesarean section. CONCLUSIONS The SSEP latency represents an accessible and reproducible method to investigate the afferent pathways from the genitourinary tract. These results could be used as normative values in studies involving genitourinary neuropathies in order to better clarify voiding and sexual dysfunctions in females.

Electrophysiological evaluation of the pudendal nerve and urethral innervation in female stress urinary incontinence

Introduction and hypothesisAlthough still a matter of debate, stress urinary incontinence (SUI) may be accompanied by damage to urethral and pelvic floor innervations, thus promoting dysfunctions of the urethral support and sphincteric closure mechanisms. The aim of this study was to analyze the pelvic floor and urethral innervations through pelvic electrophysiological tests to identify whether neurological alterations interfere with urinary continence and urethral functional activity.MethodsThis prospective study included 52 women, 33 with clinically and urodynamically proven SUI and 19 continent volunteers matched for age, height, parity, and number of vaginal deliveries by the propensity score method. The patients were divided according to the severity of urinary loss evaluated by measuring abdominal leak point pressure (ALPP). Pudendal nerve terminal motor latency (PNTML), pudendal somatosensory evoked potential (SSEP) latencies, urethral and clitoral sensory thresholds, and urethroanal reflex latency were tested.ResultsSUI and control subjects did not differ in PNTML, SSEP latency, and clitoral sensory thresholds. However, reduced responsiveness to urethral electrosensitivity and prolonged urethroanal reflex latency were detected in most incontinent patients. In addition, urethral electrosensitivity was altered in suspected intrinsic sphincteric dysfunction.ConclusionsUrethral afferent pathways can be altered in women with SUI and may play an important role in evoking intrinsic sphincteric dysfunction.

Motor unit number index and neurophysiological index as candidate biomarkers of presymptomatic motor neuron loss in amyotrophic lateral sclerosis: Munix and NI in Presymptomatic ALS

Introduction: Our objective was to determine the utility of motor unit number index (MUNIX) and neurophysiological index (NI) as surrogate biomarkers of disease progression in limbs without clinical signs of lower motor neuron (LMN) involvement from patients with slowly progressive amyotrophic lateral sclerosis (ALS). Methods: Patients with slowly progressive ALS and at least 1 clinically unaffected limb were prospectively enrolled. Clinical signs of LMN loss and results from hand‐held dynamometer (HHD), revised ALS Functional Rating Scale (ALSFRS‐R), mean‐MUNIX (from 3 different muscles), and NI were longitudinally recorded. Results: Eighteen patients with 43 presymptomatic muscles were evaluated. Twenty‐seven muscles remained clinically unaffected during study, with stable ALSFRS‐R subscores and HHD measures. However, a significant decline in mean‐MUNIX and NI was detected. Discussion: Mean‐MUNIX and NI were more sensitive than clinical measures at detecting LMN loss in presymptomatic limbs from patients with slowly progressive ALS. Therefore, these electrophysiological biomarkers should be included in early study phases as meaningful outcome measures. Muscle Nerve 58: 204–212, 2018

Neuroimaging Features in Congenital Trichomegaly: The Oliver‐McFarlane Syndrome

A 23‐year‐old woman presented to our hospital with 9 months history of progressive ataxia, visual loss since childhood due to retinitis pigmentosa and primary amenorrhea. On examination, there were also sparse scalp hair, very long and curled upwards eyelashes and short stature. Oliver‐McFarlane syndrome was suspected. Brain MRI disclosed cerebellar atrophy and hyperintense signal in corticospinal tracts on FLAIR and T2‐weighted images. Therefore, brain imaging must be thoroughly investigated in patients with suspected Oliver‐McFarlane syndrome, in order to determinate whether cerebellar atrophy and hyperintense signal in corticospinal tracts are part of this neurological condition.

Expression of praxis induction on cortical excitability in juvenile myoclonic epilepsy.

OBJECTIVE This study aimed to evaluate the effects of praxis induction on sensorimotor cortical and transcallosal excitability in juvenile myoclonic epilepsy (JME). METHODS A total of 36 subjects (18-62years) were included. The JME group was screened by video-electroencephalography neuropsychological protocol and divided into JME without praxis induction [JME-WI (n=12)], JME with praxis-induced seizures or epileptiform discharges [JME-PI (n=10)], and healthy controls (n=14). Motor and somatosensory cortical excitability and transcallosal pathways were evaluated through single-pulse transcranial magnetic stimulation (sTMS) and somatosensory evoked potentials (SEPs). RESULTS Motor and transcallosal excitabilities tested with sTMS were not different in the motor-dominant or non-dominant hemisphere among groups. Significant differences were found in cortical SEP amplitudes in the P27 component of the non-dominant hemisphere (p=0.03, Cohens d=0.98), N35 in the dominant hemisphere (p=0.04, Cohens d=0.96), and P27-35 interpeak amplitude in both somatosensory cortices of the JME-PI group (p=0.03, Cohens d=0.96; p=0.02, Cohens d=1.05) when compared with healthy controls. Giant SEPs were observed in two (16.7%) and five (50%) patients of the JME-WI and JME-PI groups, respectively. Cortical latencies did not reveal differences. CONCLUSIONS Praxis induction was associated with enhanced excitability in the somatosensory cortex of JME patients. SIGNIFICANCE These findings may help clarifying the less favorable therapeutic response in the JME-PI group and indicate identifying praxis induction as an important determinant in differentiating between JME patients.

19. Motor skills were affected by intrauterine somatosensory brain injury that mimics a brachial plexus palsy

cussion-induced rippling of the anterior thigh muscles and biceps brachii. Creatine kinase (CK) values were elevated 3-fold and acetylcholine receptor (AChR) binding antibodies were positive. Nerve conduction studies, including 2 Hz repetitive nerve stimulation were normal. Single fiber electromyography was normal. The needle examination demonstrated small motor unit potentials. Multichannel, intramuscular needle recording of thigh muscles revealed a brief discharge with a frequency of 100 Hz lasting 0.5–1 s. These discharges were much briefer than muscle rippling noted on the skin surface. Muscle biopsy showed an active inflammatory myopathy and reduced sarcolemmal caveolin-3 immunostain in a mosaic pattern. Caveolin-3 gene analysis revealed no mutation. Immunotherapy resulted in resolution of the muscle weakness and rippling and normalization of the CK and AChR antibodies. Conclusion: This case underscores the importance of caveolin-3 in the pathogenesis of iRMD. In addition, the abnormal muscle activity was not completely silent in this patient, suggesting that acquired neuromuscular hyperexcitability consists of a continuum of disorders.

18. The P18 component of the cervical median nerve somatosensory evoked responses is not reduced by vibration

cussion-induced rippling of the anterior thigh muscles and biceps brachii. Creatine kinase (CK) values were elevated 3-fold and acetylcholine receptor (AChR) binding antibodies were positive. Nerve conduction studies, including 2 Hz repetitive nerve stimulation were normal. Single fiber electromyography was normal. The needle examination demonstrated small motor unit potentials. Multichannel, intramuscular needle recording of thigh muscles revealed a brief discharge with a frequency of 100 Hz lasting 0.5–1 s. These discharges were much briefer than muscle rippling noted on the skin surface. Muscle biopsy showed an active inflammatory myopathy and reduced sarcolemmal caveolin-3 immunostain in a mosaic pattern. Caveolin-3 gene analysis revealed no mutation. Immunotherapy resulted in resolution of the muscle weakness and rippling and normalization of the CK and AChR antibodies. Conclusion: This case underscores the importance of caveolin-3 in the pathogenesis of iRMD. In addition, the abnormal muscle activity was not completely silent in this patient, suggesting that acquired neuromuscular hyperexcitability consists of a continuum of disorders.

18. Is there a P18 component after stimulation of the median nerve at the wrist

cussion-induced rippling of the anterior thigh muscles and biceps brachii. Creatine kinase (CK) values were elevated 3-fold and acetylcholine receptor (AChR) binding antibodies were positive. Nerve conduction studies, including 2 Hz repetitive nerve stimulation were normal. Single fiber electromyography was normal. The needle examination demonstrated small motor unit potentials. Multichannel, intramuscular needle recording of thigh muscles revealed a brief discharge with a frequency of 100 Hz lasting 0.5–1 s. These discharges were much briefer than muscle rippling noted on the skin surface. Muscle biopsy showed an active inflammatory myopathy and reduced sarcolemmal caveolin-3 immunostain in a mosaic pattern. Caveolin-3 gene analysis revealed no mutation. Immunotherapy resulted in resolution of the muscle weakness and rippling and normalization of the CK and AChR antibodies. Conclusion: This case underscores the importance of caveolin-3 in the pathogenesis of iRMD. In addition, the abnormal muscle activity was not completely silent in this patient, suggesting that acquired neuromuscular hyperexcitability consists of a continuum of disorders.

The P18 component of the median nerve SEP recorded from a posterior to anterior neck montage

OBJECTIVE To investigate the P18 component in the posterior to anterior neck montage after median nerve stimulation. METHODS Somatosensory evoked potentials, through electrical wrist stimulation, were collected. In 12 subjects, the presence of the P18 component was evaluated in the posterior to anterior neck montage. In 10 subjects, the effects of simultaneous vibration of the hand were evaluated. In five subjects, responses after double-pulse stimulation (ISI 20 ms) were evaluated. RESULTS The P18 component was identified in all subjects. Vibration reduced the amplitude of all components except the P18 and N18. Double-pulse stimulation reduced the amplitude of the P18 and the N18 components without significantly changing the amplitude of the other components. CONCLUSIONS The posterior to anterior neck montage allows for recording the P18 component. The amplitude reduction of all components during vibration, except N18 and P18, is interpreted as reflecting inhibitory activities at the cuneiform nucleus and at the segmental dorsal horn of the spinal cord, respectively. The reduction in the P18 component after double-pulse stimulation is compatible with previous observations on the positive component of cord dorsum potentials. SIGNIFICANCE Studying this component may add to the knowledge of the function of the spinal cord in humans.