The hindbrain and cortico-reticular pathway in adolescent idiopathic scoliosis.

AIM: To characterise the corticoreticular pathway (CRP) in a case-control cohort of adolescent idiopathic scoliosis (AIS) patients using high-resolution slice-accelerated readout-segmented echo-planar diffusion tensor imaging (DTI) to enhance the discrimination of small brainstem nuclei in comparison to automated whole-brain volumetry and tractography and their clinical correlates. MATERIALS AND METHODS: Thirty-four participants (16 AIS patients, 18 healthy controls) underwent clinical and orthopaedic assessments and brain magnetic resonance imaging (MRI) on a 3 T MRI machine. Automated whole-brain volume-based morphometry, tract-based spatial statistics analysis, and manual CRP tractography by two independent raters were performed. Intra-rater and inter-rater agreement of DTI metrics from CRP tractography were assessed by intraclass correlation coefficient. Normalised structural brain volumes and DTI metrics were compared between groups using Student's t-tests. Linear correlation analysis between imaging parameters and clinical scores was also performed. RESULTS: AIS patients demonstrated a significantly larger pons volume compared to controls (p=0.006). Significant inter-side CRP differences in mean (p=0.02) and axial diffusivity (p=0.01) were found in patients only. Asymmetry in CRP fractional anisotropy significantly correlated with the Cobb angle (p=0.03). CONCLUSION: Relative pontine hypertrophy and asymmetry in CRP DTI metrics suggest central supranuclear inter-hemispheric imbalance in AIS, and support the role of the CRP in axial muscle tone. Longitudinal evaluation of CRP DTI metrics in the prediction of AIS progression may be clinically relevant.

Interictal hemodynamic abnormality during motor activation in sporadic hemiplegic migraine: An explorative study.

INTRODUCTION: The motor weakness in sporadic hemiplegic migraine (SHM) is a poorly understood aura manifestation. Cortical spreading depression affecting motor excitability and alterations of neurovascular coupling may be integral to the development of migraine aura. METHODS: We studied 10 right-handed SHM patients and 17 healthy controls with functional near-infrared spectroscopy (fNIRS) in the interictal period. Subjects performed a finger opposition task and had real time determination of oxyhemoglobin (OxyHb) and deoxyhemoglobin (deOxyHb) changes. Recordings were completed with 10 left and 10 right sided cortical channels. RESULTS: Mean baseline to peak changes were significantly reduced in SHM patients as compared to controls bilaterally only for OxyHb measurements in the anteromedial channels. Mean time to peak changes were significant delayed in SHM patients compared to controls bilaterally largely for OxyHb measurements in the posterolateral channels, with the exception of 2 recording channels. CONCLUSIONS: Our findings suggest presence of abnormal interictal hemodynamic responses to increased metabolic demands during motor activation in SHM. These bilateral cerebrovascular changes involve OxyHb to a much larger degree than deOxyHb. Baseline to peak changes were evident more in the anteromedial channels, whereas time to peak changes were more evident in the posterolateral channels. These findings suggest that oxygen inflow into specific brain regions may be defective in SHM as opposed to oxygen utilization. Our findings suggest that in SHM, enduring hemodynamic deficits in response to an impending motor task are evident, which can be further explored in future studies, and possibly therapeutic trials.

A Comparison Study of Conventional Ultrasound and Ultrasound Strain Elastography in the Evaluation of Myopathy.

The aim of this study was to compare ultrasound strain elastography (USE) with conventional ultrasonography echogenicity (EL) in detecting muscle pathology. For conventional ultrasonography, biceps EL was obtained. For USE, elasticity index (EI) of biceps was represented as a range, from 0 (softest) to 6 (hardest). Muscle-to-fats elasticity ratio compared EI of muscle with that of surrounding fats. Color distribution of elastogram was analyzed using open-source ImageJ software showing % red, % green, and % blue within a region of interest. Increased biceps EL, decreased biceps EI, and elasticity ratio were observed in patients with myopathy. In the color elastogram, there is no significant difference in % green between healthy control and patient, but significance was observed in % red and % blue (P < 0.001). Utilization of USE parameters has increased sensitivity up to 100% compared with 63% with conventional US. It is a promising adjunct for the clinical diagnosis of myopathy.

Evaluation of the predictive performance of bleeding risk scores in patients with non-valvular atrial fibrillation on oral anticoagulants.

WHAT IS KNOWN AND OBJECTIVE: Bleeding risk scores (BRSs) aid in the assessment of oral anticoagulant-related bleeding risk in patients with atrial fibrillation. Ideally, the applicability of a BRS needs to be assessed, prior to its routine use in a population other than the original derivation cohort. Therefore, we evaluated the performance of 6 established BRSs to predict major or clinically relevant bleeding (CRB) events associated with the use of oral anticoagulant (OAC) among Malaysian patients. METHODS: The pharmacy supply database and the medical records of patients with non-valvular atrial fibrillation (NVAF) receiving warfarin, dabigatran or rivaroxaban at two tertiary hospitals were reviewed. Patients who experienced an OAC-associated major or CRB event within 12 months of follow-up, or who have received OAC therapy for at least 1 year, were identified. The BRSs were fitted separately into patient data. The discrimination and the calibration of these BRSs as well as the factors associated with bleeding events were then assessed. RESULTS: A total of 1017 patients with at least 1-year follow-up period, or those who developed a bleeding event within 1 year of OAC use, were recruited. Of which, 23 patients experienced a first major bleeding event, whereas 76 patients, a first CRB event. Multivariate logistic regression results show that age of 75 or older, prior bleeding and male gender are associated with major bleeding events. On the other hand, prior gastrointestinal bleeding, a haematocrit value of less than 30% and renal impairment are independent predictors of CRB events. All the BRSs show a satisfactory calibration for major and CRB events. Among these BRSs, only HEMORR2 HAGES (C-statistic = 0.71, 95% CI 0.60-0.82, P < .001) and ATRIA score (C-statistic = 0.70, 95% CI 0.58-0.82, P < .001) show acceptable discrimination performance for major bleeding events. All the 6 BRSs, however, lack acceptable predictive performance for CRB events. WHAT IS NEW AND CONCLUSION: To the best of our knowledge, this is the first evaluation study of the predictive performance of these 6 BRSs on clinically relevant bleeding events applied to the same cohort consisting of mainly Asian novel oral anticoagulant users. These BRSs show poor to acceptable predictive performance on OAC-induced major or CRB events. An improvement in the existing BRSs for OAC users is warranted.

Presynaptic neuromuscular transmission defect in the stiff person syndrome.

BACKGROUND: The stiff person syndrome (SPS) is a rare disorder characterized by muscular rigidity and stiffness. CASE PRESENTATIONS: We describe an SPS patient presenting with longstanding fatigue and electrophysiological evidence of presynaptic neuromuscular transmission defect, who responded to administration of pyridostigmine. In contrast, no electrophysiolgical evidence of neuromuscular transmission defect was demonstrated in 2 other SPS patients without fatigue symptoms. CONCLUSIONS: Our findings suggest that glutamic acid decarboxylase (GAD) antibodies may play a role in presynaptic neuromuscular transmission defect of SPS patients with fatigue.

Steroid Responsive Mononeuritis Multiplex in the Cronkhite-Canada Syndrome.

The Cronkhite-Canada syndrome (CCS) is a rare disorder of unknown origin characterized by generalized gastrointestinal polyposis, alopecia, hyperpigmentation, and onychodystrophy. We report a case of CCS with concomitant presentation of mononeuritis multiplex. The electrophysiological findings and steroid responsiveness suggests presence of an autoimmune mechanism.

Motor and somatosensory abnormalities are significant etiological factors for adolescent idiopathic scoliosis.

OBJECTIVE: In adolescent idiopathic scoliosis (AIS), we explore the role of lateralized motor and somatosensory abnormalities as a possible etiological factor. METHODS: Intraoperative transcranial electrical stimulation was performed in 15 AIS and 14 adult degenerative scoliosis (ADS) patients. Inter-side motor output balance (MOB) by comparing the ratios of right to left motor evoked potentials (MEP) amplitudes, and inter-side motor output excitability (MOE) computed with MEP amplitude, was determined separately for both patients groups. For somatosensory evoked potentials (SSEP), peak to peak P37 amplitudes from right and left lower limb SSEP and inter-side P37 amplitude ratios were obtained. RESULTS: Inter-side MOB was significantly asymmetric in AIS patients, contributed mainly by inter-side MOB changes in the upper than the lower limbs. Inter-side MOE comparisons of ipsilateral and contralateral MEP amplitudes were significantly different between AIS and ADS patients. Mean upper limb MEP amplitudes were significantly reduced in AIS patients. Amplitude of the right upper limb MEPs were positively correlated with inter-side MEP ratio. AIS patients show larger mean MEP amplitudes on the same side as the scoliotic curve. Overall, no correlation of Cobb's angle or total levels of scoliosis involvement with inter-side MOB and MOE parameters was found. Inter-side SSEP ratios were significantly higher in AIS patients. CONCLUSIONS: Primary dysfunctional and distributed motor output contributing to abnormalities of inter-side MOB and MOE changes involving the upper limbs is evident in AIS. Simultaneous but independent somatosensory and motor observations seen these patients suggest a central mechanism as an etiological factor.

Changes of snoring sound after relocation pharyngoplasty for obstructive sleep apnoea: the surgery reduces mean intensity in snoring which correlates well with apnoea-hypopnoea index.

OBJECTIVE: To investigate objective changes of snoring after surgery in patients with obstructive sleep apnoea (OSA) and correlate these with changes in the apnoea-hypopnoea index (AHI). DESIGN: Prospective case series. SETTING: A novel measurement, Snore Map, was used to analyse full-night snore sounds in terms of the maximal/mean intensity, peak/mean frequency, snoring index and energy type (Snore Map type, 0-4). Snore sound was classified into three bands according to frequency energy spectrum: B1 (40-300 Hz), B2 (301-850 Hz) and B3 (851-2000 Hz). PARTICIPANTS: Thirty-four male and two female OSA patients (mean age, 39 years; mean AHI, 53.1/h; mean body mass index, 26.8 kg/m(2) ) with favourable anatomic structure were consecutively enrolled. MAIN OUTCOME MEASURES: Parameters of polysomnographies and Snore Maps at baseline and six months after operation were compared. Statistical significance was set at P < 0.05. RESULTS: Thirty-two patients completed this study. The mean reduction in the total-snoring index was insignificant but there were significant decreases in total mean intensity, total peak frequency, total mean frequency and Snore Map type after surgery. There were also significant decreases in the mean intensity in all three bands, the snoring index in B2/B3 and the mean frequency in B1 postoperatively. Changes in the total mean intensity, total mean frequency, B2 mean intensity and B3 snoring index positively correlated with change in the AHI. CONCLUSIONS: Relocation pharyngoplasty significantly decreases both the snoring sound intensity and snoring frequency. These reductions are directly proportional to the improvement of OSA.

A comparison study of repetitive transcranial magnetic stimulation for tinnitus treatment in an Asian population.

BACKGROUND: Tinnitus, a subjective auditory perception of sounds or noise not triggered by external auditory stimuli, carries considerable morbidity. To date, pharmacological, physical or behavioral therapy is the mainstay of management. METHODS: We compared repetitive transcranial magnetic stimulation (rTMS) of 1000 or 2000 stimulations/day at 1 Hz and 110% of the motor threshold for 5 consecutive days over the left auditory cortex. Ratings based on the Tinnitus Handicap Inventory (THI) rating scale were completed weekly for 4 weeks. None of the patients had significant hearing impairment. RESULTS: All 28 patients (age range 21-72; 18 men) tolerated rTMS well and no adverse effects were observed. Analysis of variance (ANOVA) showed significant decrease in THI scores over the entire time period (F (1,26)=11.33, p=0.002). At every weekly time point of evaluation, ANOVA with repeated measures demonstrated significantly lower THI score compared to baseline (p<0.02 for all). RTMS treatment had resulted in tinnitus reduction in the range of 15-25% over the 4 week period. Separately, ANOVA also demonstrated significantly reducing THI for both the 1000 pulse (F (1,14)=4.8, p=0.04) and 2000 pulse (F (1,14)=6.56, p=0.02) rTMS treatment arms. Comparison of THI ratings between the 2 treatment arms did not result in significant difference (F (1,26)=1.48, p=0.24). CONCLUSIONS: The present study has revalidated the efficacy and safety of rTMS for improving tinnitus up to 4 weeks post-treatment in Asians. However, there was no significant difference with THI evaluation between the 1000 pulse and 2000 pulse treatment arms.

Correlation between acetylcholine receptor antibody levels and thymic pathology in myasthenia gravis: a review.

Myasthenia gravis is the most common chronic autoimmune neuromuscular disease. Anti-acetylcholine receptor (AChR) antibodies are found in at least 80% of patients with generalized myasthenia and have been implicated in disease pathogenesis. Thymic abnormalities are frequently found in seropositive patients, and the thymus is thought to be involved in generation of autoimmunity. This article reviews existing literature on the role of AChR antibodies in the pathogenesis of myasthenia gravis, and the correlation between AChR antibody titers and thymic pathology. Most studies found that highest titers are seen in thymic hyperplasia, followed by intermediate titers in thymoma, and lowest titers in atrophic or normal thymus. One publication found no difference between titers in thymoma and normal thymus.

Taiwan aneurysm registry: multivariate analysis of two-month, one-year, and two-year outcomes after endovascular and microsurgical treatment of ruptured aneurysms.

We compared the outcomes of endovascular coiling with microsurgical clipping of aneurysms in a Taiwanese population. In an ambi-directional cohort design, patient baseline characteristics and clinical course after treatment for ruptured subarachnoid aneurysm were abstracted from medical records from three hospitals to examine and compare differences in post-operative outcomes between those treated with endovascular coiling and those treated with microsurgical clipping. Outcomes were measured, using the modified Rankin scale, two months, one year and two years postoperatively. Of the 642 patients enrolled in the study, 281 underwent endovascular treatment and 361 underwent neurosurgery. The demographics and baseline characteristics of two groups were comparable except for a larger maximum target aneurysm lumen size (p=0.02) in the endovascular group. Patients who underwent the endovascular procedure tended to have a better quality of life than those who had neurosurgery (p<0.01). When the severity of symptom data was pooled into two groups (Rankin values 0-2 and 3-6) a statistically significant relationship was found between the severity of symptoms and age, Hunt and Hess grade, number of target aneurysms detected, and log of maximum target aneurysm lumen size (all p≤0.01). After controlling for potential confounding factors and using the lumped Rankin outcome data, no significant difference in outcome was found between the two procedures at either time point. Our study indicated that endovascular coiling achieves results comparable to surgical clipping for patients with ruptured subarachnoid aneurysms in a Taiwanese population.

A prospective pilot study of repetitive transcranial magnetic stimulation for gait dysfunction in vascular parkinsonism.

OBJECTIVE: Vascular Parkinsonism (VP) causes significant gait dysfunction in patients who otherwise have good lower limb strength. Its pathophysiology is not clearly understood, and current treatment with physical therapy remains unsatisfactory. The study explores repetitive transcranial magnetic stimulation (rTMS) as a potential new and safe therapy for VP. MATERIALS AND METHODS: We prospectively applied 5 Hz rTMS treatment to 5 patients who satisfied all the criteria for VP. Repetitive TMS was performed on 5 consecutive days and patients were assessed on (1) timed 10 m walk (T10MW), (2) Unified Parkinson's Disease Rating Scale (UPDRS) motor subsection, (3) Clinician's Global Impression of Change (CGIC), and (4) Patient's Global Impression of Change (PGIC), for up to 6 weeks post-rTMS. RESULTS: All the outcome measures were found to have improved ratings post-rTMS when compared with baseline, and were statistically significant. The T10MW showed significant improvement at 4 weeks post-rTMS with a trend towards improvement at 2 weeks post-rTMS. The UPDRS motor subscores was significantly reduced at 2 weeks, 4 weeks and 6 weeks post-rTMS. The PGIC and CGIC scores were significantly better post-rTMS. The treatment was well-tolerated and all patients completed the study. CONCLUSION: This study demonstrated for the first time that 5 sessions of rTMS could improve gait in a measurable way for up to 6 weeks without any significant side-effects. Repetitive TMS could be a potentially useful adjunct in rehabilitation of VP patients and further research is warranted.

Nucleic acid amplification test and bronchoscopy improve the diagnostic accuracy of smear-negative tuberculosis.

OBJECTIVE: To determine whether the nucleic acid amplification (NAA) test on specimens collected by bronchoscopy improves the diagnostic accuracy of pulmonary tuberculosis (PTB) in sputum-negative patients. DESIGN: Bronchoscopy was performed among smear-negative PTB suspects to collect respiratory specimens to assess the efficacy and accuracy of the Amplified Mycobacterium Tuberculosis Direct (AMTD) test in the diagnosis of PTB. RESULTS: In 105 PTB suspects, 80 were finally excluded, of whom two were false-AMTD-positive. PTB (n = 25) was diagnosed in 10 patients culture-positive for Mycobacterium Tuberculosis (7/105 bronchial wash/bronchoalveolar lavage [BW/BAL] specimens, 6/315 expectorated sputum specimens [2 positive in 2 patients; 1 positive in 2 patients], and one with both), and in 15 patients with improvement after anti-tuberculosis treatment. Among the 25 PTB patients, 20 were AMTD-positive, of whom four were culture-positive. Three AMTD-negative patients were culture-positive. The sensitivity and specificity of AMTD were respectively 80.0% and 97.5%. The diagnostic yield was higher in respiratory specimens obtained at bronchoscopy and measured by AMTD than in conventional sputum or BW/BAL culture. CONCLUSION: NAA testing on specimens collected using bronchoscopy provides a highly efficient and reliable approach in the diagnosis of PTB in smear-negative PTB suspects.

Beyond-limit light focusing in the intermediate zone.

We experimentally verify that a new nanolens of a designed plasmonic aperture can focus visible light to a single line with its width smaller than the limit of half the wavelength in the intermediate zone. The experimental measurement indicates that while the near field plays a role to increase the spot size in the near zone, it is negligible at the beyond-limit focused region; i.e., the focused light is dominated by the radiative fields. The image taken by the optical microscope shows that the fields focused have propagated to the far zone. Besides being of academic interest, the nanolens capable in achieving a lower diffraction limit in the intermediate zone is important for application possibilities.

Auditory hallucinations and migraine of possible brainstem origin.

BACKGROUND: Concurrence of migraine and hallucinations is extremely rare and the underlying mechanism is poorly understood. METHODS: We report a 22-year-old man with migraine associated with auditory hallucinations. Concurrent psychotic illness has been excluded. RESULTS: Brain MR scans showed a stable, patchy FLAIR hyperintensity over the posterolateral aspect of the left cerebral peduncle, just below the level of the red nucleus. This was felt to represent an area of gliosis based on the interval stability over 19 months. There was absence of features for aggressive neoplasms, such as lesional high cellular turnover (choline/NAA ratio >1.0) or high cerebral blood volume on advanced MR imaging with MR spectroscopy and dynamic perfusion MR. EEG and brainstem auditory evoked potentials were unremarkable. CONCLUSIONS: To our knowledge, there are no reports to date on similar auditory hallucinations in adult migraine patients, as well as with associated MRI brainstem lesions. The peduncular lesion could represent a previous migrainous infarct, and a possible analogy can be drawn from the descriptions of peduncular hallucinosis. Brainstem lesions, particularly in the midbrain and pons, have rarely been associated with this condition. It has been postulated that the damage to ascending reticular systems or thalamocortical circuitry may contribute to its pathogenesis.

Short duration repetitive transcranial magnetic stimulation for tinnitus treatment: a prospective Asian study.

BACKGROUND: Tinnitus is a subjective auditory perception of sounds or noise not triggered by external auditory stimuli. To date, treatment in severe cases is generally unsatisfactory. Characteristic functional brain imaging changes associated with tinnitus include hyperactivity encompassing both the primary auditory cortex (AC) and the secondary or associative cortex. Brief repetitive transcranial magnetic stimulation (rTMS) trains applied to the scalp overlying the hyperactive left AC is known to produce moderate tinnitus attenuation. OBJECTIVE: Although Western studies have documented the value of rTMS in tinnitus treatment, we evaluate the efficacy of a short duration rTMS protocol for the first time in the Asian setting. METHOD: Consecutive patients were recruited at our tinnitus clinic. Detailed history, examination, audiogram and baseline tinnitus scales were recorded. RTMS consisted of 1000 pulses/day at 1 Hz and 110% of the motor threshold, for five consecutive days over the left temporoparietal cortex. Tinnitus ratings were determined weekly for 4 weeks after rTMS. RESULT: Fifteen patients completed the trial; none experienced significant side effects. Repeated measures ANOVA showed significant linear decrease in Tinnitus Handicap Inventory (THI) scores over the time period (F((1,14))=4.7, p=0.04). However, none of the other parameters (severity, annoyance, effect on lifestyle and overall impression: visual analogue scale) showed beneficial outcomes. CONCLUSIONS: Our findings point to a positive effect of short duration rTMS in tinnitus treatment using the THI. However, no significant benefits were demonstrated for other subjective patient ratings. Although well tolerated and convenient, short duration rTMS may prove inadequate for modulating maladaptive plastic changes at the cortical level, and our results suggest the need for delivery of more stimuli. Future studies will utilize at least 2000 pulses/day, in line with previous experience in Western settings.

Ruptured symptomatic internal carotid artery dorsal wall aneurysm with rapid configurational change. Clinical experience and management outcome: an original article.

BACKGROUND: Aneurysms located at non-branching sites, protruding from the dorsal wall of the supraclinoid internal carotid artery (ICA) with rapid configurational changes, were retrospectively reviewed in effort to identify and characterize these high-risk aneurysms. METHODS: A total of 447 patients with 491 intracranial aneurysms were treated from March 2005 to August 2008, and of these, eight patients had ICA dorsal wall aneurysms. Four of them suffered subarachnoid hemorrhage (SAH), and all had aneurysms undergoing rapid configuration changes during the treatment course. Digital subtraction cerebral angiography (DSA) performed soon after the SAH events. Data analyzed were patient age, sex, Hunt and Kosnik grade, time interval from first DSA to second DSA, aneurysm treatment, and modified Rankin scale score after treatment for 3 months. Success or failure of therapeutic management was examined among the patients. RESULTS: Digital subtraction cerebral angiography showed only lesions with small bulges in the dorsal walls of the ICAs. However, the patients underwent DSA again for re-bleeding or for post-treatment follow-up, confirming the SAH source. ICA dorsal wall aneurysms with rapid growth and configurational changes were found on subsequent DSA studies. CONCLUSIONS: Among the four patients, ICA dorsal wall aneurysms underwent rapid growth with configurational change from a blister type to a saccular type despite different management. ICA trapping including the lesion segment can be considered as the first treatment option if the balloon occlusion test (BOT) is successful. If a BOT is not tolerated by the patient, extracranial-intracranial bypass revascularization surgery with endovascular ICA occlusion is another treatment option.

A study of acupuncture in Asian patients: clinical aspects and effects on cortical excitability.

OBJECTIVE: To determine the effect of acupuncture on the phosphene threshold, by transcranial magnetic stimulation (TMS), and the clinical effect of acupuncture on headache frequency, duration and severity. METHODS: Twenty-one patients (16 women; mean age 46 years; range 23-61 years, 17 Chinese, 2 Malays, 2 Indians) underwent 10 acupuncture sessions scheduled twice a week for 5 weeks. The lowest TMS intensity to elicit phosphene perception is defined as the phosphene threshold. TMS was performed before the first and last sessions, and at 2 months' follow-up. RESULTS: Acupuncture resulted in reduction of headache frequency, duration and severity over the course of treatment. However, this was not accompanied by a corresponding increase in the phosphene threshold over a similar time course. The baseline threshold before acupuncture treatment had no predictive value for outcome of treatment. CONCLUSIONS: Although acupuncture was effective in treating migraine, the use of occipital cortex excitability as an adjunctive parameter to evaluate treatment response was not suitable. The relief of migraine with acupuncture may be related to separate neural pathways independent of occipital or visual processes in the human brain.