Effects of Clozapine on Cortical Inhibition: A Transcranial Magnetic Stimulation Follow-up Study.

BACKGROUND: Preclinical and clinical investigations have revealed deficits in cortical inhibition in individuals with schizophrenia. Transcranial magnetic stimulation, a commonly used noninvasive measurement technique, is used for assessing these deficits. Limited research has been conducted on the effects of antipsychotic medications on cortical inhibition. This study aimed to evaluate the effects of clozapine on cortical inhibition with transcranial magnetic stimulation longitudinally and compare it with unaffected controls. METHODS: Ten patients who started clozapine were assessed at baseline, with 8 reassessed after 4 months. Eight age- and sex-matched unaffected controls were included. Psychopathology, neurocognitive performance, formal thought disorder, and disability were assessed, and the cortical excitability parameters (resting motor threshold, cortical silent period, short-interval intracortical inhibition, intracortical facilitation, and short-latency afferent inhibition [SAI]) were measured at baseline and four months after clozapine treatment. RESULTS: Resting motor threshold, ICF, and SAI were significantly different between patients and controls at baseline, whereas resting motor threshold, SAI, and ICF became similar to controls after clozapine with only ICF having a trend for significance. Clozapine prolonged cortical silent period significantly in the patients. CONCLUSIONS: This is the first study to investigate the effect of clozapine on SAI, a potential cholinergic biomarker, and the first follow-up study to investigate the relationship between the effects of clozapine on cortical inhibition and cognition. Clozapine seems to cause an increase in cortical inhibition through GABAergic and possibly cholinergic mechanisms. However, additional follow-up studies with larger sample sizes are required to reach more robust conclusions.

Winged Scapula: Clinical and Electrophysiological Features and Common Causes Based on 20 Years of Experience in a Referral Center in Turkey.

PURPOSE: Winged scapula (WS) is a functionally disabling problem and it occurs because of neurogenic causes frequently. The authors aimed to assess WS patients by physical and electrodiagnostic examinations as well as some further investigations and define the common causes of WS. METHODS: The authors reviewed clinical and neurophysiological findings of 52 patients who were referred for electrodiagnostic examination because of WS in the period of 20 years. RESULTS: The mean age was 39 (range, 11-73) years and 32 were male patients. Right side was involved in 60% of patients (n = 31). According to electrodiagnostic examinations, 44 patients (85%) had neurogenic causes; 29 spinal accessory nerve palsy (17 occurred after surgical procedure), nine long thoracic nerve palsy (four occurred after strenuous activity), two dorsal scapular nerve (both neuralgic amyotrophy), one long thoracic nerve and spinal accessory nerve (relevant with strenuous trauma), one spinal accessory nerve and dorsal scapular nerve palsies (after surgical procedure and radiotherapy), one C5-7 radiculopathy (avulsion), and one brachial plexopathy (obstetric trauma). Five patients (10%) had muscle-related findings (four facio-scapulo-humeral dystrophy and one Duchenne muscular dystrophia) and three patients (5%) had normal findings (bone-joint related). CONCLUSIONS: This study presents a relatively large series of patients with WS because of several causes from a referral tertiary EMG laboratory. The authors found that spinal accessory nerve palsy after neck surgery is the most common cause and long thoracic nerve palsy is the second common cause of unilateral WS. Electrodiagnostic examinations should be performed in WS patients to establish exact diagnosis and reveal some coexistence of WS causes.

Multimodal integration and modulation of visual and somatosensory inputs on the corticospinal excitability.

OBJECTIVE: Corticospinal excitability may be affected by various sensory inputs under physiological conditions. In this study, we aimed to investigate the corticospinal excitability by using multimodal conditioning paradigms of combined somatosensory electrical and visual stimulation to understand the sensory-motor integration. METHODS: We examined motor evoked potentials (MEP) obtained by using transcranial magnetic stimulation (TMS) that were conditioned by using a single goggle-light-emitting diode (LED) stimulation, peripheral nerve electrical stimulation (short latency afferent inhibition protocol), or a combination of both (goggle-LED+electrical stimulation) at different interstimulus intervals (ISIs) in 14 healthy volunteers. RESULTS: We found MEP inhibition at ISIs of 50-60 ms using the conditioned goggle-LED stimulation. The combined goggle-LED stimulation at a 60 ms ISI resulted in an additional inhibition to the electrical stimulation. CONCLUSIONS: Visual inputs cause significant modulatory effects on the corticospinal excitability. Combined visual and somatosensory stimuli integrate probably via different neural circuits and/or interneuron populations. To our knowledge, multimodal integration of visual and somatosensory inputs by using TMS-short latency inhibition protocol have been evaluated via electrophysiological methods for the first time in this study.

The functional and structural evaluation of small fibers in asymptomatic carriers of TTR p.Val50Met (Val30Met) mutation.

Therapeutic advances in hereditary amyloid transthyretin (ATTRv) amyloidosis with polyneuropathy extended life expectancy and delayed symptom progression especially in patients with early disease. Thus, detection and monitoring of asymptomatic carriers gained importance. However, there is still limited consensus on genetic screening of ATTRv-polyneuropathy patients' family members and diagnostic tests that must be done in the follow-up. In this study, we followed prospectively five asymptomatic carriers of a family with ATTRV30M (p.Val50Met) mutation by different diagnostic tests for three years. The carriers were followed by neurological examination, nerve conduction studies, sympathetic skin response test, heart rate variability, SFN-SIQ and DN4 questionnaires, quantitative sensory testing (QST), skin biopsy and in vivo corneal confocal microscopy. Nerve conduction studies, sympathetic skin response test and heart rate variability were normal in all for three years. Baseline QST and SFN-SIQ were normal but became abnormal during follow-up of two individuals who developed small fiber neuropathy symptoms. Baseline intraepidermal nerve fiber density was low in three carriers and decreased to below normative values in all during follow-up, while corneal sub-basal nerve density was low in all carriers compared to controls during the entire follow-up. Thus, our study showed that SFN-SIQ and QST are useful diagnostic tools to detect the transition to symptomatic ATTRv-polyneuropathy.

The Effect of the Activation of the Core Muscles on Tremor in a Patient with Multiple Sclerosis.

BACKGROUND: Trunk stabilization is important in providing postural control and extremity movements, and is maintained by the muscles called "core". OBJECTIVE: The aim of this report was to demonstrate the effect of core muscles contraction on upper extremity tremor. MATERIALS AND METHODS: A 22-year-old Multiple Sclerosis patient with right extremity ataxia was included in this report. Scale of Assessment and Rating Ataxia (SARA), Expanded Disability Status Scale (EDSS), Accelerometric Tremorogram and Purdue Peg Board Test (PPBT) were performed. Assessments were made with and without the core muscles contraction. RESULTS: The total score of SARA decreased from 16 to 14 due to the reduction of dysmetria and tremor scores. Tremor amplitude decreased with contraction in tremorogram. At the 1st position, the tremor amplitude changed from -14.6 before the contraction to -18.3 after the contraction. At position 2, 6 Hz tremor was disappeared with contraction. In the PPBT, ataxic extremity performance increased from 5 to 7. CONCLUSION: Contraction of core muscles reduced postural tremor and improved upper extremity performance. It should be considered planning the training program of ataxic MS patients.

Urinary incontinence as a cause of depression and sexual dysfunction: Questionnaire-based study.

INTRODUCTION: Urinary incontinence is a severe and common health problem. In this study, we aimed to assess severity of sexual dysfunction and depression in patients with urinary incontinence. MATERIALS AND METHODS: The study has been conducted between 2015 and 2017. Age, body mass index, accompanying health problems, Over Active Bladder (OAB) symptom score, Type of urinary incontinence, Beck Depression Scale were assessed for all patients. International Index of Erectile Function-5 (IIEF-5) was used for male patients in order to assess sexual dysfunction. Index of Female Sexual Function (IFSF) and Female Sexual Distress Scale (FSDS) were used in female patients in order to assess sexual dysfunction. RESULTS: 33 patients have been included in the study (Male-12: Urge-10/Stress-1/Mixed-1/Female-21: Urge-10/Stress-6/Mixed-5). Mean age of all patients was 47.9 (Male-49.3/Female-47.2). Mean Body Mass Index for all patients was 23.2 (Male-25.9/Female-21.8). Mean OAB score was 24.3 for all patients (Male-27.5: Urge-28.6/Stress-17/Mixed-27/Female-22.5: Urge-24.2/Stress:21.3/Mixed-20.6). Mean Beck Depression Result for all patients was 20.9 (Male-18.5: Urge-20.2/Stress-9/Mixt-11/Female-22.4: Urge-19.1/Stress-20.3/Mixed-31.6). Mean IIEF-5 score for male patients was 39.5 (Urge-41.4/Stress-55/Mixed-5). Mean IFSF score for female patients was 19.9 (Urge-17.9/Stress-21.3/Mixed-22.4) and mean FSDS score for female patients was 22.1 (Urge-22.3/Stress-23.1/Mixed-20.8). DISCUSSION: Most of the patients that have been included in the study were diagnosed as urge incontinence. When assessing the OAB scores, they were higher in urge incontinence group. Beck depression results showed higher scores in female patients and it was higher in urge group of male patients and mixt group of female patients. Sexual dysfunction rates were found to be higher for both genders.

The Clinical Characteristics and Neurophysiological Assessments of the Occipital Cortex in Visual Snow Syndrome With or Without Migraine.

OBJECTIVE: Visual snow syndrome (VS) is mainly characterized by flickering, little dots in both visual fields. The recognition of the clinical entity of VS has been increasing recently. Diagnosis is based on patient reports and not better accounted for by another diagnosis. BACKGROUND: The exact pathophysiology of this syndrome is still unknown. In this study, our aim was to investigate the role of neurophysiological assessments of the occipital cortex in VS patients with (VSm ) or without migraine (VSwom ) and the healthy control (HC). METHODS: To assess the occipital cortex hyperexcitability, we conducted a prospective, observational study to investigate the habituation/potentiation response by repetitive pattern reversal visual evoked potentials (rVEP) and examined the phosphene thresholds (PT) by transcranial magnetic stimulation in VS patients with or without migraine who were admitted to our tertiary headache clinic and the healthy control. RESULTS: Twenty-nine volunteers were recruited. The VSm (n = 10), the VSwom (n = 7), and the HC group (n = 12) did not differ demographically. Flickering and floaters were reported in all VS patients and flickering in the dark was the most distressing symptomatology in both VS groups. Higher VAS scores for palinopsia (trailing), photophobia, and concentration difficulty were more frequently self-reported by VSm patients. The HC demonstrated habituation; however, there was loss of habituation response and decreased PTs in both groups of VS patients. The N1P1 VEP amplitude ratios of the 10th/1st block from right and left eye stimulation disclosed higher values (lack of habituation) in VSm (1.04 ± 0.2 and 1.06 ± 0.2) and the VSwom (1.05 ± 0.2 and 0.96 ± 0.08) patients compared to the healthy control (0.75 ± 0.1 and 0.79 ± 0.1), P = .002 from right eye and P = .003 from left eye. In the post hoc analysis the VS patients did not differ according to the presence of migraine from right or left eye stimulations (both P > .999). The left occipital cortex PTs were lower in VSm (58.00 ± 6.60) and VSwom (62.14 ± 11.53) and higher in the HC (71.33 ± 5.56) P = .009. In the post hoc analysis the VS patients did not differ according to the presence of migraine (P > .999). The right occipital cortex PTs were lower in VSm (60.30 ± 8.15) and VSwom (62.00 ± 10.95), higher in the HC (69.67 ± 8.04); however, statistically, groups did not differ (P = .087). CONCLUSIONS: The loss of habituation and lower threshold for occipital cortex excitability were demonstrated electrophysiologically in VS patients. While statistically significant loss of habituation was seen in both VS patients (with or without migraine) in the right eye, statistically significant loss of habituation in the left eye and decreased threshold of left occipital cortex excitability was seen in visual snow with migraine patients. These findings may provide new insights on "visual snow" pathophysiology and serve as an objective and quantitative assessment tool in VS patients.