Amplitude In Patients Research Articles

Sacral Reflex Characteristics of Patients with Multiple System Atrophy.

Objectives To observe and analyze the parameters of the sacral reflex and pudendal nerve somatosensory evoked potential (SSEP) in patients with multiple system atrophy (MSA) with respect to factors such as age, disease course, and subtype and provide evidence for the clinical diagnosis of MSA. Materials and Methods A total of 51 MSA patients and 30 healthy controls were selected from the First Affiliated Hospital of Wenzhou Medical University from May 2013 to November 2015. Electrophysiological sacral reflex detection and SSEP detection were performed using the Keypoint EMG/EP system. The extraction rate, latency, and amplitude of the sacral reflex and SSEP in the MSA group and control group were compared. Results The sacral reflex latency and amplitude in patients with MSA were statistically different from those of the healthy controls. The latency of sacral reflex increases with the prolongation of the disease course, and the amplitude and initiation rate decrease with the prolongation of the disease course. There was no significant difference in sacral reflex latency and amplitude between MSA patients of different ages and subtypes. There was no significant difference in the latency or amplitude of SSEP between the MSA group and healthy control group. Conclusions The latency of sacral reflex increases with the prolongation of the disease course, and the amplitude and extraction rate decrease with the prolongation of the disease course. There was no significant difference in the parameters of sacral reflex between young MSA patients and elderly patients. And there was no statistically significant difference between MSA-P subtypes and MSA-C subtypes. This trial is registered with ISRCTNCR2009041.

S138. A PRELIMINARY STUDY ON ILLNESS INSIGHT MEASURED BY THE RELATIONSHIP BETWEEN ERN PATTERNS AND MMPI RESULTS IN PATIENTS WITH SCHIZOPHRENIA

BackgroundThe error-related negativity (ERN) is an event-related brain potential waveform peaking about 50 ms after error commission in choice-response tasks and may indicate a conflict between neural representations of correct and incorrect responses as stimulus processing continues after an error. Most previous studies consistently reported a reduced event-related potential (ERP) amplitude in patients with schizophrenia compared with normal controls. Some self-report measures derived from the Minnesota Multiphasic Personality Inventory (MMPI) are known to be associated with clinical observations in carefully diagnosed schizophrenia patients. In the MMPI, an elevation of the validity scales in the MMPI best distinguishes patients with schizophrenia from patients feigning schizophrenia, and the MMPI validity scales are known to provide a good reflection of illness insight in schizophrenia.Both the amplitudes of the Pe of the ERN and the scores of the MMPI validity scales are supposed to reflect, directly or indirectly, the illness insight of patients with schizophrenia.When the abovementioned results obtained in studies on the ERN or MMPI in patients with schizophrenia are taken together, we may presume that a certain relationship exists between the results of the ERN and the MMPI validity scales in terms of illness insight.Interestingly, as far as we know, there are no published studies that looked at the results of the ERN and the MMPI at the same time.We tried to perform an integrative examination of the relationship between the results of the ERN and MMPI tests in patients with schizophrenia as a method of measuring illness insight in patients with schizophrenia.MethodsWe reviewed the medical records of who were diagnosed as having schizophrenia based on the DSM-5.The protocol for the general ERP and ERN are as follows.64 channels with M1 and M2 as reference electrodesImpedance: < 1 kΩERN: 1000 msERPs were recorded while the patients were performing the Stroop test. Independently of the ERP recording, the patients received an MMPI test.The relationship between the latency and amplitude of the ERN and the demographic and clinical variables was analyzed by a t-test, and correlation analyses were used for categorical and continuous variables. The statistical significance was set at p < 0.05.ResultsOf the total 18 patients (8 men and 10 women; age = 41.6 ± 15.8) whose data were reviewed, 5 were excluded due to poor understanding of the ERN instructions.Table 1. Demographic and clinical information of participated patientswith schizophreniaTable 2. Partial correlation coefficients on variables after controlling for age and gender.DiscussionThe results for the association of ERN amplitude and latency with the MMPI validity scales showed that latency measures were positively associated with the MMPI validity scales that were related to the assessment of the overestimation of responses. Individuals who tended to exaggerate problems through over-responses showed increased ERN amplitude but decreased ERN Pe amplitude. Although caution is needed to interpret the results of this study due to limitations, our results suggest that ERP measurement could act as a biological marker for endophenotype in schizophrenia. Furthermore, ERP measurement might be used to visualize or to make concrete illness insight, which by its nature is difficult to measure objectively.ReferencesYeung N, Botvinick MM, Cohen JD. The neural basis of error detection: conflict monitoring and the error-related negativity. Psychol Rev. 2004 Oct;111(4):931–959.Kansal V, Patriciu I, Kiang M. Illness insight and neurophysiological error-processing deficits in schizophrenia. Schizophr Res. 2014 Jun;156(1):122–7.

Effect of chronic stretching interventions on the mechanical properties of muscles in patients with stroke: A systematic review.

Muscle contractures are common after stroke and their treatment usually involves stretching. However, recent meta-analyses concluded that stretching does not increase passive joint amplitudes in patients with stroke. The effectiveness of treatment is usually evaluated by measuring range of motion alone; however, assessing the effects of stretching on the structural and mechanical properties of muscle by evaluating the torque-angle relationship can help in understanding the effects of stretching. Although several studies have evaluated this, the effects remain unclear. A systematic review of the literature on the effectiveness of stretching procedures for which the outcomes included a measurement of torque associated with range of motion or muscle structure (e.g., fascicle length) in stroke survivors. PubMed, ScienceDirect and PEDro databases were searched by 2 independent reviewers for relevant studies on the effects of chronic stretching interventions (>4 weeks) that evaluated joint angle and passive torque or muscle structure or stiffness. The quality of the studies was assessed with the PEDro scale. Eight randomized clinical trials (total of 290 participants) met the inclusion criteria, with highly variable sample characteristics (at risk/existing contractures), program objectives (prevent/treat contractures) and duration (from 4 to 52 weeks) and volume of stretching (1 to 586 hr). All studies were classified as high quality (>6/10 PEDro score). Six studies focused on the upper limb. Many programs were less than 12 weeks (n=7 studies) and did not change mechanical/structural properties. The longest intervention (52 weeks) increased muscle fascicle length and thickness (plantar flexors). Long interventions involving high stretching volumes and/or loads may have effects on muscle/joint mechanical properties, for preventing/treating contractures after stroke injury, but need to be further explored before firm conclusions are drawn.

Electroretinogram and Visual Evoked Potentials in Patients with Type ll Diabetes Mellitus

Background: Retinopathy is a severe and common complication of diabetes. The pathology seems to be characterized not only by the involvement of retinal micro vessels but also by a real neuropathy. Before the onset of micro vascular lesions, the retina of the eye undergoes subtle functional changes that are not detectable by fundus photography. Electrophysiological investigations allow a more detailed study of the visual function. These techniques are safe, repeatable, quick, and objective. Objective: To study pattern electroretinogram (PERG) and pattern reversal visual evoked potentials (PRVEP) in type 2 diabetic patients without diabetic retinopathy (DR) or with mild non-proliferative DR (mNPDR) to detect changes by comparing with those of healthy control. And to assess the correlation of the parameters with diabetes duration and the level of Glycosylated Haemoglobin A1c (HbA1c). Materials and Methods: It was a cross-sectional study, included two groups (diabetic patients and the healthy). Age range was preset at 40-65 years. For all the participants, a detailed clinical history was collected, a comprehensive ophthalmic examination and thorough blood investigations were performed, then {PRVEP (60', 15'), PERG} were recorded and (waveform, peak time, amplitude) of tests components were analyzed. Results: Mean (P100, N135) peak times of PRVEP were statistically significantly delayed in (50) eyes of type 2 diabetics without DR when compared to (36) eyes of control (p-value<0.01), abnormalities in waveforms like (double peaks, broad peak) were also observed in diabetics. There were alterations in other parameters (amplitudes of PRVEP, peak times and amplitudes of PERG) but the changes were not statistically significant. No statistically significant changes were found in (6) eyes of diabetic patients with mNPDR. No statistically significant correlation was obtained between diabetes duration or the level of HbA1c and delay of peak times or reduce amplitudes in patients. Conclusions: Electrophysiological tests are sensitive and useful investigations for the early identification of visual dysfunctions before the development of overt retinopathy in type 2 diabetics. PRVEP is more sensitive than PERG to monitor alterations and it may be sufficient to screen the patients in this stage.

Neural correlates of performance monitoring in adult patients with Gilles de la Tourette syndrome: A study of event-related potentials

ObjectivesGilles de la Tourette syndrome (GTS) is a neuropsychiatric condition characterized by motor and vocal tics. There is undoubtedly basal ganglia involvement, which are also important for cognitive processes including performance monitoring and interference resolution. We investigated these functions in adult patients with GTS compared to healthy controls (HCs). MethodsWe compared a group of N = 23 adult patients with GTS to N = 27 HC on a flanker task during an EEG recording. Reaction times and error rates were recorded, as well as N2 and Ne/ERN amplitudes. The N2 is an index of interference resolution. The Ne/ERN is a negative fronto-central component, occurring when participants make mistakes. ResultsPatients’ reaction times were enhanced on incongruent trials compared to HC. Electrophysiological data revealed more frontal components, as well as significantly increased Ne/ERN amplitudes in patients with GTS compared to HC (p = 0.026). ConclusionsAltered electrophysiological correlates of error processing in adult patients with GTS compared to HC cannot be attributed to differential error probabilities. Potentially, patients recruit compensatory resources from frontal networks to maintain behavioural performance. SignificanceThis study gives further insight into cognitive deficits of patients with GTS, and the underlying neural processes of these functions.

Establishing a reference range for thromboelastography maximum amplitude in patients administrating with antiplatelet drugs.

ObjectiveWe aimed to establish the reference range of thromboelastograph (TEG) maximum amplitude (MA) in patients taking antiplatelet drugs.MethodsBetween August 2015 and July 2018, a total of 4614 patients administrating with antiplatelet drugs (clopidogrel and aspirin) were retrospectively analyzed in this study. For MAA parameter, we used the 10th and 90th percentiles to establish a reference range. The Spearman correlation was used for the correlation analysis among the inhibition rate of adenosine diphosphate (ADP%) and MAADP, inhibition rate of arachidonic acid (AA%) and MAAA. Then, through receiver operating characteristic (ROC) curve analysis of the best cutoff point, the reference ranges of MAADP and MAAA could be deduced. Consistency evaluation was performed by statistical analysis of ADP% and MAADP, AA% and MAAA pairing for 4459 patients.ResultsThe reference range of MAA was 8.1‐25.8 mm. The reference range of MAADP was 19.8‐43.2 mm, and the corresponding sensitivity of two endpoints was 0.796, 0.856 and specificity were 0.897, 0.904, respectively. The reference range of MAAA was 18.9‐37.7 mm, and the corresponding sensitivity of two endpoints was 0.819, 0.829 and specificity were 0.922, 0.896, respectively. The inconsistency rate of ADP% and MAADP, and AA% and MAAA was 20.1% (898 cases) and 16.6% (738 cases), respectively.ConclusionsThe reference range of MAADP and MAAA established by us were better in sensitivity and specificity. MAADP and MAAA were more accurate than conventional inhibition rate analysis in guidance of antiplatelet therapy, especially in patients with excessive low MA or high MAA.

Intraoperative electromyography has a favorable impact on facial nerve function in patients with parotid gland tumor

The aim of the present study was to evaluate the clinical usefulness of intraoperative neuromonitoring and its influence on surgery and especially the onset of facial nerve palsy. Important aspect was neurophysiological examination before and after removal of parotid gland tumor. The type, size and localization of the tumor were also examined. We included 72 patients into our study. The group of 50 patients, after parotid gland surgery without the use of neuromonitoring (group I) and the group of 24 patients operated with neuromonitoring of the facial nerve (group II). Each patient had clinical neurological examination performed, as well as the electrophysiological examination of the facial nerve before and 1 month after the surgery. Electrophysiological examination of the facial nerve included a blink reflex test and bilateral electroneurography (ENoG). In our results, one month after the surgery, the normal function of the facial nerve (grade I in House-Brackmann scale) was found in 87.5% of patients operated with neuromonitoring, whereas in patients operated without the monitoring, normal nerve function was found in 26% of patients. Interestingly, neurophysiological examination did not reveal any statistical differences in the values of latency and amplitude in patients before and after surgery in both groups. The average duration of operations without monitoring was 100.4 minutes, and with the use of neuromonitoring 86.25 minutes. The level of statistical significance was p = 0.052, however. In conclusion, the use of intraoperative facial nerve monitoring reduces the risk of temporary facial nerve palsy and may shorten time of the surgery.

Serial Visual Evoked Potentials in Patients with Craniosynostosis and Invasive Intracranial Pressure Monitoring.

This study aimed to detect the ability of pattern visual evoked potentials to detect visual pathway dysfunction in a cohort of patients with craniosynostosis who also had invasive intracranial pressure measurement. A retrospective review was conducted on craniosynostosis patients who had invasive intracranial pressure measurement and at least one pattern visual evoked potentials test. Reversal pattern visual evoked potentials were performed with both eyes open. Thirteen patients met the inclusion criteria (mean age at intracranial pressure measurement, 5.7 years). Seven patients had raised intracranial pressure, and of these, five (71.4 percent) had abnormal or deteriorated pattern visual evoked potentials parameters on serial testing, whereas all patients (100 percent) with normal intracranial pressure had normal pattern visual evoked potentials amplitude and latency. Four of the five patients (80 percent) with raised intracranial pressure and abnormal pattern visual evoked potentials did not show evidence of papilledema. The mean latency in patients with raised intracranial pressure (118.7 msec) was longer than in those with normal intracranial pressure (108.1 msec), although it did not reach statistical significance (p = 0.09), whereas the mean amplitude in patients with raised intracranial pressure (12.4 µV) was significantly lower than in patients with normal intracranial pressure (23.3 µV) (p = 0.03). The authors' results showed that serial pattern visual evoked potentials testing was able to detect visual pathway dysfunction resulting from raised intracranial pressure in five of seven craniosynostosis patients, and of these five patients, 80 percent had no evidence of papilledema, demonstrating the utility of serial pattern visual evoked potentials in follow-up of the visual function in craniosynostosis patients. CLINICAL QUESTION/LEVEL OF EVIDENCE:: Diagnostic, II.

Differential response to vibration of three forms of scoliosis during axial cyclic loading: a finite element study

BackgroundScoliosis is a serious disease that can affect all segments of society. Few studies have investigated the response to vibration of differing sinusoidal axial cyclic loading frequencies for different forms of scoliosis in the lumbar spine.MethodsIn this study, four finite element models, comprising a healthy spine, Lenke-A, Lenke-B and Lenke-C scoliosis of the lumbar S1-L1 region were developed. Modal analysis extracted resonant frequencies of the FE models with an upper body mass of 40 kg and 400 N preload. A transient dynamic analysis was performed to obtain the response to vibration of models under a sinusoidal axial loading of ± 40N at frequencies of 3, 5, 7, 9, 11 and 13 Hz using an upper body mass of 40 kg and 400 N preload.ResultsThe first-order resonant frequencies of healthy, Lenke-A, Lenke-B and Lenke-C spines were 9.2, 3.9, 4.6 and 5.7 Hz, respectively. A Lenke-A lumbar spine was more likely to deform at a lower vibration frequency and Lenke-C deformed more easily at a higher vibration frequency. Furthermore, the vibration amplitude in the Y-direction (left-right) was greatest and least in the Z-direction (top-bottom). The frequency of cyclic loading closest to the resonant frequency resulted in a maximum value of peak-to-peak vibrational displacement. Furthermore, the vibrational amplitudes in patients with scoliosis were larger than they were in healthy subjects. In addition, axial displacement of the vertebrae in the healthy spine changed steadily whereas fluctuations in the scoliotic vertebrae in scoliosis patients were greater than that of other vertebrae.ConclusionsDifferent forms of scoliosis may have different vibrational characteristics, the scoliotic vertebrae being the weak link in scoliosis under loading condition of whole body vibration. Scoliosis was more sensitive to this form of vibration. Where the frequency of axial cyclic vibrational loading of the lumbar spine was closer to its resonant frequency, the vibrational amplitude was larger. These results suggest that vibration will exacerbate the degree of scoliosis and so such patients should reduce their exposure to vibration. Clinical treatment should pay attention to the scoliotic vertebrae and reduce their vibration. These findings may assist in the clinical prevention and treatment of scoliosis.

Compensatory Neural Recruitment for Error-Related Cerebral Activity in Patients with Moderate-To-Severe Obstructive Sleep Apnea.

(1) Background: Although it is known that obstructive sleep apnea (OSA) impairs action-monitoring function, there is only limited information regarding the associated cerebral substrate underlying this phenomenon. (2) Methods: The modified Flanker task, error-related event-related potentials (ERPs), namely, error-related negativity (ERN) and error positivity (Pe), and functional magnetic resonance imaging (fMRI) were used to evaluate neural activities and the functional connectivity underlying action-monitoring dysfunction in patients with different severities of OSA. (3) Results: A total of 14 control (Cont) subjects, 17 patients with moderate OSA (mOSA), and 10 patients with severe OSA (sOSA) were enrolled. A significant decline in posterror correction rate was observed in the modified Flanker task when patients with mOSA were compared with Cont subjects. Comparison between patients with mOSA and sOSA did not reveal any significant difference. In the analysis of ERPs, ERN and Pe exhibited declined amplitudes in patients with mOSA compared with Cont subjects, which were found to increase in patients with sOSA. Results of fMRI revealed a decreased correlation in multiple anterior cingulate cortex functional-connected areas in patients with mOSA compared with Cont subjects. However, these areas appeared to be reconnected in patients with sOSA. (4) Conclusions: The behavioral, neurophysiological, and functional image findings obtained in this study suggest that mOSA leads to action-monitoring dysfunction; however, compensatory neural recruitment might have contributed to the maintenance of the action-monitoring function in patients with sOSA.

Three Weeks of rTMS Treatment Maintains Clinical Improvement But Not Electrophysiological Changes in Patients With Depression: A 6-Week Follow-Up Pilot Study.

Our previous study demonstrated that 3 weeks of repetitive transcranial magnetic stimulation (rTMS) increases P200 amplitudes and improves the symptoms of depression and anxiety in depression patients. In the present study, we investigated whether 3 weeks of rTMS treatment maintained the P200 amplitude in patients with depression at 6 weeks of follow-up. We measured the 6-week maintenance effects of rTMS using clinical questionnaires and an auditory oddball paradigm. Twenty-one patients with medication-resistant major depression participated in this pilot study. All patients underwent rTMS treatment for 3 weeks; they completed clinical ratings and performed the auditory oddball task at the pre-treatment, post-treatment, and 6-week follow-up visit (3 weeks after finishing rTMS treatment). The results revealed an increase in P200 amplitudes as well as improvements in the symptoms of depression and anxiety by 3 weeks of rTMS treatment. Furthermore, the results demonstrated maintenance effects on clinical ratings at 6-week follow-up. Depression and anxiety scales showed improvements in post-treatment and maintenance effects at the 6-week follow-up. Although P200 amplitude showed a significant main effect for 3 time points (baseline, post-treatment, and 6-week follow-up visit), at 2 time point comparisons, P200 amplitudes significantly increased in post-treatment compared to those of the baseline condition but did not show the maintenance effects of long-term rTMS at the 6-week follow-up compared to those of the baseline condition ( p = .173, Bonferroni correction). Standardized low-resolution brain electromagnetic tomography (sLORETA) for P200 showed significant activation in the left middle frontal gyrus in post-treatment but no significant activation at the 6-week follow-up. Moreover, the amplitudes of overall topographic distribution were reduced at 6 weeks of follow-up. The 3 weeks of rTMS treatment induced the maintenance of the improvements in the symptoms of depression and anxiety. However, considering the results of the event-related potential (ERP) and sLORETA, 3 weeks of rTMS treatment may not be sufficient to maintain this improvement, implying that a treatment period of more than 3 weeks may be required to reveal the electrophysiological maintenance effect of rTMS.

P70-F Vestibular-evoked myogenic potentials for the diagnosis of superior canal dehiscence syndrome

Background Superior canal dehiscence syndrome (SCDS) is a clinical entity characterized by vertigo and oscillopsia in response to sound (Tullio phenomenon), pressure (Hennebert sign) and vestibular stimulation with Valsalva maneuvers, disequilibrium, autophony, bone-conductive hyperacusis and pulsatile tinnitus. Vestibular-evoked myogenic potentials (VEMPs) is a technique used to determine the function of the otolithic organs. The aim of the study is to examine the VEMPs characteristics in patients with SCDS. Material and methods 5 patients with SCDS between 2016 and 2018 were included. VEMPs were recorded from the ipsilateral sternocleidomastoid muscle (cVEMP) and periocular sites (oVEMP). 500 Hz tone burst at 105 dB nHL was used as stimuli at 5 Hz stimulation rate and averaged for 200 repetitions. Bandpass-filtered between 20 Hz and 2 kHz. Statistical analysis included paired sample Mann-Whitney U test in the SPSS program. We compared the latency and amplitude of the affected ear with the healthy ear. Data shown as mean ± SE. Results The mean age of the test group was 61.4 ± 8.08 years with 3 males and 2 females. Comparing the affected ear and healthy ear: oVEMP amplitude (33.2 ± 5.9/8 ± 2.1 μ V, p 0.11); cVEMPamplitude (158.8 ± 41.2/125 ± 29.86 μ V, p > 0.56); cVEMP-p13 (15.2 ± 0.4/15.1 ± 0.7 ms, p > 0.8); In 100% of patients with SCDS, oVEMP amplitudes were significantly higher than normal values (p > 0.01 Mann-Whitney U). No statistically significant differences were obtained in the remaining parameters. Conclusions oVEMP amplitude in patients diagnosed as SCDS are significantly higher than normal values. These techniques have proven to be useful for diagnosis of superior canal dehiscence syndrome.

Slowing of Alpha Waves on EEG, an Early Marker of Minimal Hepatic Encephalopathy

Introduction: Minimal Hepatic Encephalopathy (MHE) is the mildest form of spectrum of Hepatic Encephalopathy (HE) which remains undiagnosed due to lack of awareness. MHE has a negative effect on patient's daily functioning due to cognitive impairment. Electro-Encephalo-Gram (EEG) and Mini Mental State Examination (MMSE) are useful in early diagnosis and follow up of MHE. Aim: To study evidence of MHE in patients with liver cirrhosis by psychometric tests and also its correlation with EEG changes. Materials and Methods: The study was carried out as a prospective case control study of 70 patients diagnosed with Cirrhosis of liver, over a period of two years in accordance with European Association for the Study of the Liver (EASL) and Asociacion Latinoamericana parael Estudio del Higado (ALEH) criteria with MMSE score &gt;24 and were diagnosed as Minimal Hepatic Encephalopathy if 2 out of 3 psychometric tests were abnormal EEG was performed in them and was compared with 70 healthy controls. Results: Study showed male predominance (90%) with mean age of 45.49 ± 11.76. Alcohol related cirrhosis (70%) was found to be more common than HBV (8.57%) and HCV (2.86%) infection related cirrhosis. Pedal edema, icterus, pallor and ascites were the most common presenting manifestations. Most cirrhotic cases (80%) were under Child Pugh Class-A. On USG of abdomen all cases had Coarse echotexture and nodular surface of liver among them 11 cases had Hepatomegaly, 10 cases had splenomegaly, 42 cases had ascites and 24 cases had increased portal venous diameter of mean size 14.02 ± 0.48 mm. MMSE score of all selected cirrhotic cases was &gt;24. Psychometric Tests i.e. Number Connection Test-A, Number Connection Test-B and Line tracing test were performed in all selected cirrhotic cases and they were not able to perform it within designated time. All cases were subjected to EEG and compared with equal number of comparable healthy controls, which shows change in frequency and amplitude of Alpha wave which was highly significant whereas no significant changes of frequency and amplitude of Beta, Theta and Delta waves between cases and controls. Conclusion: There is significant changes in alpha wave frequency and amplitude in patients with minimal hepatic encephalopathy.

Relationship between Macular Vessel Density and Focal Electroretinograms in Early Normal Tension Glaucoma

ABSTRACTPurpose: To evaluate the relationship between the macular vessel density and photopic negative response (PhNR) amplitude of focal electroretinograms (ERGs) in patients with early-stage normal tension glaucoma (NTG).Materials and Methods: This prospective cross-sectional study included a total of 42 subjects with early-stage NTG. Optical coherence tomography angiography was used to measure macular vessel density, and focal ERGs were elicited by a white light stimulus (30 cd/m2) with background light (1.5 cd/m2). The amplitude of the PhNR was measured from the peak of the b-wave to the PhNR trough. Mean visual field sensitivity was measured by the Humphrey Field Analyzer (HFA) program central 10–2. Spearman’s coefficients were used to evaluate the correlation between the macular vessel density, PhNR amplitude, mean deviation (MD) of the HFA 10–2, retinal nerve fiber layer (RNFL) thickness, and ganglion cell complex (GCC) thickness measured by spectral domain-optical coherence tomography.Results: The mean MD of the HFA 10–2 was −2.0 ± 3.2 dB. The PhNR amplitude significantly correlated with the macular vessel density (r = 0.420, P = 0.006), but not with the MD, GCC thickness, or RNFL thickness. The macular vessel density significantly correlated with the MD (r = 0.364, P = 0.018) and RNFL thickness (r = 0.369, P = 0.016), but not with GCC thickness (r = 0.266, P = 0.089).Conclusions: Macular vessel density significantly correlated with PhNR amplitude in patients with early-stage NTG, suggesting that microvascular alterations are associated with functional changes recorded by focal ERG in very early-stage glaucoma.

Withdrawal from acute medication normalises short-term cortical synaptic potentiation in medication overuse headache

To study the effects of a standard acute medication withdrawal program on short-term cortical plasticity mechanisms in patients with medication overuse headache (MOH). Thirteen patients with MOH and 16 healthy volunteers underwent repetitive transcranial magnetic stimulation (rTMS) over the left motor cortex; in patients with MOH, recordings were performed before and after a 3-week medication withdrawal program. Ten trains of 10 stimuli each (120% resting motor threshold) were delivered at 1Hz or 5Hz in two separate sessions in a randomised order. Motor evoked potential (MEP) amplitudes were measured from the right first dorsal interosseous muscle and the slope of the linear regression line from the first to the tenth stimuli was calculated for each participant. All subjects exhibited MEP amplitude inhibition in response to 1Hz rTMS. Alternatively, the 5-Hz trains of rTMS inhibited rather than potentiated MEP amplitudes in patients with MOH. The physiological potentiating effect of 5Hz rTMS on MEP amplitudes was restored after drug withdrawal and in proportion with the percentage reduction in monthly headache days in patients with MOH. The results suggest that acute medication withdrawal normalises brain responses in patients with MOH. Clinical improvements after medication withdrawal may reflect the reversal of neurophysiological dysfunction. Accordingly, medication withdrawal should be offered to patients with MOH as early as possible in order to prevent the development of more pronounced alterations in brain plasticity.

Effect of 3-month α-lipoic acid treatment on sural nerve conduction velocity and amplitude in patients with diabetic neuropathy: a pilot study.

Effect of 3-month α-lipoic acid treatment on sural nerve conduction velocity and amplitude in patients with diabetic neuropathy: a pilot study.

The Effects of Trabeculectomy on Ocular Pulse Amplitude in Patients with Glaucoma.

Objectives:This study aimed to investigate whether trabeculectomy and its intraocular pressure (IOP)-lowering effect have an effect on ocular pulse amplitude (OPA) in glaucoma patients.Methods:Thirty-five consecutive patients with glaucoma (70 eyes) who had undergone unilateral first-time trabeculectomy between April and November 2012 were enrolled in this retrospective study. Patients with intraoperative or postoperative complications were excluded from this study. The eye that underwent trabeculectomy was considered the study eye; the fellow eye was used as the control eye. OPA and IOP were measured by Pascal dynamic contour tonometry (DCT), IOP was measured by Goldmann applanation tonometry (GAT), and systolic and diastolic blood pressure and heart rate were measured before and one month after trabeculectomy. The change in the pre- and postoperative values was compared between the two eyes.Results:The study sample included 17 male and 18 female patients with a mean age of 60.83±13.46 years. The mean preoperative GAT, DCT and OPA values in the study eyes were 24.97±8.26, 31.23±10.55 and 4.22±1.77 mmHg, respectively. One month after trabeculectomy, the GAT, DCT and OPA values were 12.83±4.35, 20.28±7.34 and 2.96±1.66 mmHg, respectively. There was a significant decrease in OPA after filtration surgery in the study eyes (p<0.001), but not in the control eyes (p>0.05). Changes in OPA were positively correlated with changes in IOP (p<0.05), and a significant association was found between OPA and IOP, and as measured by DCT (Regression coefficient = 0.093 [0.041–0.145]) and GAT (Regression coefficient = 0.093 [0.013–0.173]).Conclusion:There was a significant decrease in OPA in the eyes that underwent trabeculectomy, and the change in OPA after surgery was significantly different in the study eyes in comparison to the change in OPA in the control eyes. The OPA changes were strongly correlated with the IOP changes in the study eyes.

Effects of conflict and strategic processing on neural responses to errors in schizophrenia

The error-related negativity (ERN) and error-positivity (Pe) are commonly linked to error-detection and strategic processing. Studies have documented the influence of conflict probability on ERN amplitude. However, the influence of conflict probability on ERN/Pe in schizophrenia, where such components are reduced, is unknown. A modified flanker paradigm was used to examine how the probability of conflict modulates ERN and Pe amplitudes in patients with schizophrenia (n = 33) and healthy controls (n = 25). Increased ERN was observed in response to errors on low probability, incongruent trials. No such differences were observed in Pe. While ERN and Pe showed significantly reduced amplitudes in patients relative to controls, patients showed normal condition-dependent ERN and reaction-time modulation. This suggests that while the neural mechanisms generating the ERN and Pe are compromised in schizophrenia, those modulating task performance strategy and neurophysiological responses to errors based on conflict probability are intact.

A left bundle branch block activation sequence and ventricular pacing influence voltage amplitudes: an in vivo and in silico study.

The aim of this study was to investigate the influence of the activation sequence on voltage amplitudes by evaluating regional voltage differences during a left bundle branch block (LBBB) activation sequence vs. a normal synchronous activation sequence and by evaluating pacing-induced voltage differences. Twenty-one patients and three computer models without scar were studied. Regional voltage amplitudes were evaluated in nine LBBB patients who underwent endocardial electro-anatomic mapping (EAM). Pacing-induced voltage differences were evaluated in 12 patients who underwent epicardial EAM during intrinsic rhythm and right ventricular (RV) pacing. Three computer models customized for LBBB patients were created. Changes in voltage amplitudes after an LBBB (intrinsic), a normal synchronous, an RV pacing, and a left ventricular pacing activation sequence were assessed in the computer models. Unipolar voltage amplitudes in patients were approximately 4.5 mV (4.4-4.7 mV, ∼33%) lower in the septum when compared with other segments. A normal synchronous activation sequence in the computer models normalized voltage amplitudes in the septum. Pacing-induced differences were larger in electrograms with higher voltage amplitudes during intrinsic rhythm and furthermore larger and more variable at the epicardium [mean absolute difference: 3.6-6.2 mV, 40-53% of intrinsic value; interquartile range (IQR) differences: 53-63% of intrinsic value] compared to the endocardium (mean absolute difference: 3.3-3.8 mV, 28-30% of intrinsic value; IQR differences: 37-40% of intrinsic value). In patients and computer models without scar, lower septal unipolar voltage amplitudes are exclusively associated with an LBBB activation sequence. Pacing substantially affects voltage amplitudes, particularly at the epicardium.

Monocyte-to-high density lipoprotein ratio is associated with a decreased compound muscle action potential amplitude in patients with diabetic axonal polyneuropathy.

The monocyte-to-high density lipoprotein ratio (MHR) has recently been implemented as an indicator of inflammation and oxidative stress. The present study characterized MHR in patients with diabetic polyneuropathy (DPN), in which oxidative stress and microvascular damage play a role in pathogenesis, relative to patients with non-DPN, diabetic patients without polyneuropathy, and healthy individuals. We further aimed to evaluate the association between MHR and the decreased compound muscle action potential (CMAP) amplitude of patients with diabetic axonal polyneuropathy.We enrolled 90 patients with DPN, 75 patients with nonDPN, 92 diabetic patients without polyneuropathy, and 67 healthy individuals; The monocyte, high-density lipoprotein cholesterol (HDL-C) values were obtained for all participants and MHR was calculated for each individual. Intergroup comparison was performed. The relationship between MHR and the posterior tibial nerve CMAP amplitudes was examined.Statistically significant negative correlation was observed between MHR and the posterior tibial nerve CMAP amplitudes of patients with DPN. The MHR values of the patients with DPN were significantly higher than those of the patients with non-DPN, diabetic patients without polyneuropathy and the control group.This study demonstrated that diabetic patients with higher MHR values may be more likely to develop polyneuropathy.