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.

Risks and impacts of thromboembolism in patients with pancreatic cancer

INTRODUCTION

Patients with pancreatic cancer have a high risk of thromboembolism (TE), which may increase mortality. Most relevant studies have been conducted in Western populations. We investigated risk factors for TE in a predominantly Chinese population of patients with pancreatic cancer, along with effects of TE on overall survival.

METHODS

This retrospective cohort study included patients diagnosed with exocrine pancreatic cancer in Prince of Wales Hospital in Hong Kong between 2010 and 2015. Data regarding patient demographics, World Health Organization performance status, stage, treatment, TE-related information, and time of death (if applicable) were retrieved from electronic medical records. Univariate and multivariable logistic regression analyses were performed to identify risk factors for TE. Survival analyses were performed using Kaplan-Meier analysis and Cox proportional hazards regression.

RESULTS

In total, 365 patients were included in the study. The overall incidence of TE (14.8%) was lower than in Western populations. In univariate logistic regression analysis, stage IV disease and non-head pancreatic cancer were significantly associated with TE (both P=0.01). Multivariable logistic regression analysis showed that stage IV disease was a significant risk factor (odds ratio=1.08, 95% confidence interval [CI]=1.00-1.17; P=0.046). Median overall survival did not significantly differ between patients with and without TE (4.88 months vs 7.80 months, hazard ratio=1.08, 95% CI=0.80-1.49; P=0.58) and between patients with TE who received anticoagulation treatment or not (5.63 months vs 4.77 months, hazard ratio=0.72, 95% CI=0.40-1.29; P=0.27).

CONCLUSION

The incidence of TE was low in our Chinese cohort. Stage IV disease increased the risk of TE. Overall survival was not affected by TE or its treatment.

Huntingtin Overexpression Does Not Alter Overall Survival in Murine Cancer Models

A reduced incidence of various forms of cancer has been reported in Huntington's disease patients and may be due to pro-apoptotic effects of mutant huntingtin. We tested this hypothesis by assessing the effects of huntingtin protein overexpression on survival in two murine cancer models. We generated YAC HD mice containing human huntingtin transgenes with various CAG tract lengths (YAC18, YAC72, YAC128) on either an Msh2 or p53 null background which have increased cancer incidence. In both mouse models of cancer, the overexpression of either mutant or wild-type huntingtin had no significant effect on overall survival. These results do not support the hypothesis that mutant huntingtin expression is protective against cancer.

Effects of primary granulocyte-colony stimulating factor prophylaxis on neutropenic toxicity and chemotherapy dose delivery in Chinese patients with breast cancer who received adjuvant docetaxel plus cyclophosphamide chemotherapy: a retrospective cohort study

INTRODUCTION

This study was performed to examine the effects of primary granulocyte-colony stimulating factor (G-CSF) prophylaxis on neutropenic toxicity, chemotherapy delivery, and hospitalisation among Chinese patients with breast cancer in Hong Kong.

METHODS

This retrospective study included patients with breast cancer who received adjuvant docetaxel plus cyclophosphamide chemotherapy from November 2007 to October 2013 at Princess Margaret Hospital. Data were collected regarding the usage of G-CSF prophylaxis; incidences of grade 3 or 4 neutropenia, febrile neutropenia, non-neutropenic fever, and infection; hospital admissions, and chemotherapy dose delivery. Patients who began to receive G-CSF prophylaxis during the first cycle of chemotherapy and continued such prophylaxis in subsequent cycles were regarded as the primary G-CSF prophylaxis group.

RESULTS

In total, 231 female Chinese patients with breast cancer were included in the analysis. Overall, 193 (83.5%) patients received primary G-CSF prophylaxis. The demographics and tumour characteristics were comparable between patients with and without primary G-CSF prophylaxis. Primary G-CSF prophylaxis significantly reduced febrile neutropenia incidence from 31.6% to 14.5% (relative risk=0.45, 95% confidence interval=0.25-0.81). Primary G-CSF prophylaxis also significantly reduced the incidence of grade 3 or 4 neutropenia from 57.9% to 24.7% (relative risk=0.43, 95% confidence interval=0.30-0.62) and the incidence of febrile neutropenia-related hospital admission from 31.6% to 12.4% (P=0.025). Finally, it enabled more patients to receive adequate chemotherapy dose delivery.

CONCLUSION

Primary G-CSF prophylaxis effectively reduced the incidences of grade 3 or 4 neutropenia and febrile neutropenia, while enabling adequate chemotherapy dose delivery and reducing hospital admissions among Chinese patients with breast cancer who received adjuvant docetaxel plus cyclophosphamide chemotherapy.

Periventricular White Matter Abnormalities on Diffusion Tensor Imaging of Postural Instability Gait Disorder Parkinsonism

BACKGROUND AND PURPOSE

Postural instability gait disorder is a motor subtype of Parkinson disease associated with predominant gait dysfunction. We investigated the periventricular white matter comprising longitudinal, thalamic, and callosal fibers using diffusion tensor MR Imaging and examined clinical correlates in a cohort of patients with Parkinson disease and postural instability gait disorder and healthy controls.

MATERIALS AND METHODS

All subjects underwent the Tinetti Gait and Balance Assessment and brain MR imaging. The DTI indices (fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity) from ROIs dropped over the superior and inferior longitudinal fasciculi, inferior fronto-occipital fasciculus, anterior thalamic radiation, anterior and posterior limbs of the internal capsule, and the genu and body of corpus callosum were evaluated.

RESULTS

Our findings showed that the superior longitudinal fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, anterior thalamic radiation, genu of the corpus callosum, and body of the corpus callosum are more affected in postural instability gait disorder than in those with Parkinson disease or healthy controls, with more group differences among the longitudinal fibers. Only the callosal fibers differentiated the postural instability gait disorder and Parkinson disease groups. DTI measures in the superior longitudinal fasciculus, frontostriatal fibers (anterior thalamic radiation, anterior limb of the internal capsule), and genu of the corpus callosum fibers correlated with clinical gait severity.

CONCLUSIONS

Findings from this case-control cohort lend further evidence to the role of extranigral pathology and, specifically, the periventricular fibers in the pathophysiology of postural instability gait disorder.

Depression, anxiety, and apathy in Parkinson's disease: insights from neuroimaging studies

Depression, anxiety and apathy are common mood disturbances in Parkinson's disease (PD) but their pathophysiology is unclear. Advanced neuroimaging has been increasingly used to unravel neural substrates linked to these disturbances. A systematic review is provided of neuroimaging findings in depression, anxiety and apathy in PD. A PubMed, MEDLINE and EMBASE search of peer‐reviewed original research articles on these mood disturbances in PD identified 38 studies on depression, eight on anxiety and 14 on apathy in PD. Most of the imaging studies used either position emission tomography or single‐photon emission computed tomography techniques. These studies generally suggest increased neural activity in the prefrontal regions and decreased functional connectivity between the prefrontal−limbic networks in depressed patients. Functional imaging studies revealed an inverse correlation between dopaminergic density in the caudate and putamen with the severity of anxiety in PD. There was no consistent correlation between dopaminergic density of thalamus and anxiety. Studies demonstrated both positive and inverse correlations between apathy and metabolism or activity in the striatum, amygdalar, prefrontal, temporal and parietal regions. The clinical variability of study subjects and differences in image pre‐processing and analytical strategies may contribute to discrepant findings in these studies. Both nigrostriatal and extra‐nigrostriatal pathways (in particular the frontal region and its connecting areas) are affected in mood disorders in PD. Identifying the relative contributions of these neural pathways in PD patients with overlapping motor and mood symptoms could provide new pathophysiological clues for the development of better therapeutic targets for affected patients.

Magnetic Resonance Imaging of Asians with Multiple Sclerosis was Similar to that of the West

Magnetic resonance imaging (MRI) of the brain is the most important paraclinical diagnostic test in multiple sclerosis (MS). The appearance of MRI in Asians with MS is not well defined. We retrospectively surveyed the first brain and spinal cord MRI in patients diagnosed to have MS, according to Poser's criteria in seven regions throughout Asia to define the MRI changes among Asians with MS. There were 101 patients with first brain, and 86 with first spinal cord MRI, 66 of whom had both. The brain MRI showed a mean of 17 lesions per patient in T2 weighted images, mostly asymptomatic. Almost all the lesions were in the white matter, particularly in the juxtacortical, deep and periventricular white matter. A third of the lesions were greater than 5 mm, 14% enhanced with gadolinium. There were more supratentorial than infratentorial lesions at a ratio of 7.5: 1. Ninety five percent of the spinal cord lesions were in cervical and thoracic regions, 34% enhanced with gadolinium. The lesions extended over a mean of 3.6 +/- 3.3 vertebral bodies in length. Fifty (50%) of the brain and 54 (63%) of the spinal MRI patients had the optic-spinal form of MS. The MRI of the optic-spinal and classical groups of patients were similar in appearance and distribution, except that the optic-spinal MS patients have fewer brain but longer and more severe spinal cord lesions. In conclusion, the brain and spinal cord MRI of Asian patients with MS was similar to that of the West, although, in this study, Asian MS patients had larger spinal cord lesions.

Efficacy and safety of deferasirox at low and high iron burdens: results from the EPIC magnetic resonance imaging substudy

The effect of deferasirox dosing tailored for iron burden and iron loading based on liver iron concentration (LIC) was assessed over 1 year in less versus more heavily iron-overloaded patients in a substudy of the Evaluation of Patients' Iron Chelation with Exjade®. Deferasirox starting dose was 10-30 mg/kg/day, depending on blood transfusion frequency, with recommended dose adjustments every 3 months. Therapeutic goals were LIC maintenance or reduction in patients with baseline LIC <7 or ≥7 mg Fe/g dry weight (dw), respectively. Changes in LIC (R2-magnetic resonance imaging) and serum ferritin after 1 year were assessed. Adverse events (AEs) and laboratory parameters were monitored throughout. Of 374 patients, 71 and 303 had baseline LIC <7 and ≥7 mg Fe/g dw, respectively; mean deferasirox doses were 20.7 and 27.1 mg/kg/day (overall average time to dose increase, 24 weeks). At 1 year, mean LIC and median serum ferritin levels were maintained in the low-iron cohort (-0.02 ± 2.4 mg Fe/g dw, -57 ng/mL; P = not significant) and significantly decreased in the high-iron cohort (-6.1 ± 9.1 mg Fe/g dw, -830 ng/mL; P < 0.0001). Drug-related gastrointestinal AEs, mostly mild to moderate, were more frequently reported in the <7 versus ≥7 mg Fe/g dw cohort (39.4 versus 20.8 %; P = 0.001) and were not confounded by diagnosis, dosing, ethnicity, or hepatitis B and/or C history. Reported serum creatinine increases did not increase in low- versus high-iron cohort patients. Deferasirox doses of 20 mg/kg/day maintained LIC <7 mg Fe/g dw and doses of 30 mg/kg/day were required for net iron reduction in the high-iron cohort, with clinically manageable safety profiles. The higher incidence of gastrointestinal AEs at lower iron burdens requires further investigation.

Visceral adipose tissue, but not waist circumference is a better measure of metabolic risk in Singaporean Chinese and Indian men

OBJECTIVES

Visceral adipose tissue (VAT) is an independent risk factor in cardiometabolic diseases and is commonly measured by computed tomography (CT). It is measured clinically by waist circumference (WC). The L4/5 intervertebral space VAT (L4/5 VAT) is traditionally used to represent total VAT volume. We set out to determine (1) the level of intervertebral space on CT that best approximates the total VAT volume; (2) compare the association between WC and VAT in Singaporean Chinese and Indian; and (3) examine the correlation between VAT and cardiometabolic risk factors.

SUBJECTS

A total of 60 Chinese and 60 Asian Indian men older than 60 years were recruited. Their medical history was taken and anthropometry was measured. Fasting glucose, insulin, lipids, adipokines and inflammatory markers were measured. Insulin resistance was evaluated by homeostasis model assessment-insulin resistance. VAT was determined by CT. Total VAT volume was calculated in 22 patients from VAT areas at seven intervertebral levels. The optimal VAT area most representative of total VAT volume was determined and used for all patients to approximate total VAT volume.

RESULTS

The VAT area at L2/3 intervertebral space (L2/3 VAT) correlated almost perfectly with VAT volume (R(2)=0.974 and 0.946 for Chinese and Indians, respectively). SUBJECTS from the two races had similar height, weight, body mass index (BMI), WC and L2/3 VAT but more Indian men had hypertension, hyperlipidemia and type 2 diabetes mellitus. WC was correlated with the L2/3 VAT area in both Chinese (r=0.484, P<0.001) and Indian subjects (r=0.366, P=0.004) without racial difference (P=0.2 for interaction term). L2/3 VAT also correlated better with cardiometabolic risk factors, adipokines and C-reactive protein than WC, BMI or L4/5 VAT.

CONCLUSION

The L2-L3 intervertebral space was the best anatomic level for a single-slice CT cross-sectional area measurement of VAT to approximate total body visceral adipose volume in this population of Chinese and Asian Indian men older than 60 years. L2/3 VAT was better correlated with multiple cardiovascular risk factors, adipokines and inflammatory marker than either L4/5 VAT, WC or BMI.

Ministry of Health clinical practice guidelines: depression

The Ministry of Health (MOH) have updated the clinical practice guidelines on Depression to provide doctors and patients in Singapore with evidence-based treatment for depression. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the MOH clinical practice guidelines on Depression, for the information of readers of the Singapore Medical Journal. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website: http://www.moh.gov.sg/content/moh_web/home/Publications/guidelines/cpg/2012/depression.html. The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

Ministry of Health clinical practice guidelines: schizophrenia

The Ministry of Health (MOH) has updated the clinical practice guidelines on Schizophrenia to provide doctors and patients in Singapore with evidence-based treatment for schizophrenia. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the MOH clinical practice guidelines on Schizophrenia, for the information of readers of the Singapore Medical Journal. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website: http://www.moh.gov. sg/mohcorp/publications.aspx?id=26138. The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

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.

High-resolution ultrasound in the evaluation and prognosis of Bell's palsy

INTRODUCTION

Bell's palsy is a commonly encountered paralysis of the facial nerve occurring worldwide. Prognosis for Bell's palsy is good, but the proportion of patients with poor outcomes may reach 30%. Ultrasound (US) may provide a novel approach for evaluating and prognosticating Bell's palsy, in comparison with known electrophysiological techniques.

METHODS

In this study, we measured the diameter of the distal facial (VII) nerve using US in patients with Bell's palsy treated with prednisolone, in comparison with healthy controls. Blink reflex and VII nerve conduction studies were also performed. Studies were prospective and performed within 1 week of disease onset.

RESULTS

Our results have shown that diameter of the distal VII nerve is a good predictor of favorable (positive predictive value: 100%) and bad outcomes (negative predictive value: 77%) in Bell's palsy at 3 months after clinical presentation. Furthermore, we also noted the lack of correlation of VII diameter with conventional VII nerve conduction studies (NCS) and blink reflex studies. US was superior to VII nerve conduction and blink reflex studies in outcome prediction.

CONCLUSIONS

This first study utilizing US in Bell's palsy highlights its role in outcome prediction and contributes to our understanding of recovery processes in this common neurological disorder.

Electrophysiological evidence of cerebellar fiber system involvement in the Miller Fisher syndrome

BACKGROUND

In the Miller Fisher syndrome (MFS), ataxia may be due involvement of Ia afferents and the cerebellum. Transcranial magnetic stimulation (TMS) over the cerebellum is known to interfere transiently with normal function.

METHODS

In this study, we utilized a previously described TMS protocol over the cerebellum in combination with ballistic movements to investigate cerebellar dysfunction in MFS patients.

RESULTS

The agonist (biceps) reaction time in MFS patients during a motor cancellation task was not significantly reduced during the initial TMS study. However, during the repeat TMS study, significant reduction was seen for all patients, in tandem with clinical recovery. There was significant correlation between anti-GQ1b IgG titers and change in agonist reaction time between the initial and repeat TMS studies.

CONCLUSIONS

TMS likely affected horizontally orientated parallel fibers in the cerebellar molecular layer. During disease onset, antibody binding may have interfered with facilitation of reaction time during motor cancellation tasks seen in normal subjects. Normalization of reaction time facilitation corresponded to resolution of antibody-mediated interference in the molecular layer. Our study has provided evidence suggesting parallel fiber involvement in MFS, and suggested a role of anti-GQ1b IgG antibody in these changes.

Unrelated cord blood transplantation in children--a 10-year experience from UMMC

Children who would benefit from a haematopoietic stem cell transplantation often lacked a compatible sibling donor. Unrelated cord blood transplantation was offered as an alternative donor source for patients with a variety of malignant and non-malignant diseases who had no further treatment options. Cord blood units were sourced from various international cord blood registries. The median nucleated and CD34+ cell doses were 8.7 x 10(7)/kg and 2.6 x 10(5)/kg respectively. In spite of adequate cell doses, a high rate of non-engraftment of 32% was observed. Acute graft-versus-host disease (GVHD) occurred in 14 out of the 15 patients who engrafted with 53% being grade III to IV GVHD. The five year disease free survival was 40.7% with infection and GVHD being the commonest causes of death. The five year disease free survival was 20.5% and 60.7% for malignant and non-malignant diseases respectively.

VNTR markers for qualitative evaluation of engraftment in unrelated cord blood transplantations

Allogeneic stem cell transplantation is a treatment option for malignant and non-malignant disorders in children. For children with no HLA-matched sibling or related stem cell donors, there is the option of unrelated cord blood donors. At the University of Malaya Medical Centre (UMMC) in Kuala Lumpur, the first unrelated cord blood transplantation (CBT) was performed in October 1997. All unrelated CBT performed in UMMC relied on cord blood units imported from overseas. DNA typing with variable number of tandem repeat (VNTR) loci was done to qualitatively evaluate engraftment in 15 unrelated CBT. In all the fifteen cases that were evaluated, molecular evidence of engraftment or non-engraftment correlated with the clinical findings.

Cutaneous silent periods in the evaluation of cord compression in cervical spondylosis

OBJECTIVE

The clinical diagnosis of cervical spondylotic myelopathy (CSM) may be challenging in patients with cervical spondylosis (CS). Routine nerve conduction studies (NCS) may not evaluate cord compression adequately.

METHODS

We obtained cutaneous silent periods (CSP) in 26 consecutive patients presenting with clinical features of CS, in comparison with 30 normal controls. The results were also compared with transcranial magnetic stimulation (TMS) findings, and magnetic resonance imaging of the cervical cord as the gold standard.

RESULTS

CSP findings showed similarly high sensitivity of up to 96% with TMS in evaluating cervical cord dysfunction.

CONCLUSION

In specific clinical settings, CSP is of value for the diagnosis of CSM in CS. CSP measurement is advocated as a simple and rapid diagnostic adjunct to NCS in evaluating CS patients with possible cord compromise.

Young onset hemifacial spasm

INTRODUCTION

Hemifacial spasm (HFS) frequently affects middle aged individuals and the clinical features and etiology have been well reported. However, there is limited data on the exact pathogenesis in young-onset HFS. If age is a major determinant of the etiology or influences the presentation of HFS, there may be clinical differences between the young and elderly HFS patients.

OBJECTIVES

We determined the prevalence, clinical and imaging features of young-onset HFS (age of onset<or=30 years) in a tertiary referral center. These data were compared with old onset (age of onset>or=65 years) HFS patients.

METHODS

We examined consecutive patients clinically diagnosed with HFS in a tertiary referral center. The clinical (demographics, clinical presentation, severity of HFS, associated medical conditions and other variables) and imaging findings of young onset patients and old onset patients were tabulated and compared.

RESULTS

Amongst 230 consecutive HFS patients, 15 (6.5%) were young-onset HFS and 50 (21.7%) were old-onset HFS. In the young-onset HFS, the mean age of onset of symptoms was 26.5+/-6.5 (6-30) years, with 80% women and 75.0% of young onset HFS having neurovascular compression (NVC) of the root exit zone (REZ) of the facial nerve on the ipsilateral side; 86.7% had initial onset of twitching in the upper eyelids that later progressed to the lower facial muscles. While the prevalence of hypertension, diabetes mellitus and other associated vascular disorders in late onset HFS was higher than in young onset groups, the clinical features and frequency of NVC of the facial REZ between the two groups were similar.

CONCLUSIONS

We demonstrated a 6.5% frequency of young-onset HFS in our cohort of HFS and their clinical presentation was similar to the old onset patients. Genetic, anatomic or other unidentified factors may contribute to NVC in young-onset HFS.

Exploring the relationship between Parkinson's disease and hemifacial spasm

Case reports of co-existent Parkinson's disease (PD) and hemifacial spasm (HFS) suggest that there may be a relationship between these conditions. Three of 300 (1%) PD patients presented with HFS compared with 0/300 (0%) controls. The mean age of the three PD patients with HFS was 68.7 +/- 8.0 (60-76) years, with the majority having left-sided HFS. All three patients developed HFS symptoms at around the onset of PD and they were significantly older than the 100 patients with HFS alone (P < 0.05). Our study demonstrated no significant increased risk of HFS amongst the general PD population and hence HFS symptoms are unlikely to be of clinical importance for most PD patients.

Transcranial magnetic stimulation screening for cord compression in cervical spondylosis

OBJECTIVE

Cervical spondylosis (CS) often results in various degrees of cord compression, which can be evaluated functionally with transcranial magnetic stimulation (TMS). We investigate the use of TMS as a screening tool for myelopathy in CS.

METHODS

We prospectively studied 231 patients classified into Groups 1 to 4 based on MRI grading of severity of cord compromise. TMS elicited central motor conduction times and motor evoked potential (MEP) amplitudes in all 4 limbs. The results were compared with those from 45 healthy controls.

RESULTS

TMS showed 98% sensitivity and 98% specificity for cord abnormality using MRI as reference standard.

CONCLUSIONS

MEP abnormalities are useful for electrophysiological evaluation of cord compression in CS. While TMS is not a substitute for MRI, it is of value as a rapid, inexpensive and non-invasive technique for screening patients before MRI studies.

Ventrolateral medullary compression in hypertensive patients with hemifacial spasm

In a patient-controlled study, the authors demonstrated a significantly higher prevalence of rostral ventrolateral medulla (VLM) compression in hypertensive patients with hemifacial spasm (HFS) compared with age-, sex-, race-, disease duration-, and disease severity-matched normotensive patients with HFS (p = 0.02). Hypertensive HFS patients were more likely to have a greater severity of neurovascular compression at the VLM compared with normotensive HFS patients (p = 0.008). VLM compression is associated with risk of hypertension in this study population.

Difficulties with prenatal diagnosis of the Walker-Warburg syndrome

We describe a postnatally diagnosed case of Walker-Warburg syndrome--a form of congenital muscular dystrophy with lissencephaly and eye abnormalities. We reviewed the literature to highlight its clinico-radiological diagnostic features and discuss the difficulties encountered with prenatal diagnosis, especially in cases with no positive family history. An increased awareness of this rare but lethal condition, and a high index of suspicion during routine antenatal ultrasound, could prompt further advanced fetal ultrasonography and magnetic resonance imaging, and aid in timely prenatal diagnosis, management, and counseling.

Pectoralis major motor evoked potentials in cervical spondylosis

Myelopathy is a severe complication of cervical spondylosis (CS). We studied 27 consecutive patients with CS referred for evaluation for possible myelopathy using transcranial magnetic stimulation. The findings were compared with those from 20 normal controls. Magnetic resonance imaging was utilized to assess the degree of cord compromise. Central motor conduction time (CMCT) abnormalities showed equivalent diagnostic yield with pectoralis major (PM) recordings, as compared with combined first dorsal interossei and abductor hallucis recordings. Our findings show that CMCT measurement with PM recordings is of value as a diagnostic adjunct in the electrophysiological evaluation of myelopathy in CS.

Hemidystonia precipitated by acute pontine infarct

Hemidystonia is frequently due to an underlying structural lesion in the basal ganglia and thalamus. It has been suggested that a preserved corticospinal tract may be required for hemidystonia to manifest. We provide the first report of a patient who presented with rapid-onset hemidystonia precipitated by an acute pontine infarct demonstrated on diffusion-weighted magnetic resonance imaging. Acute dysregulation of pallidal efferents to the pedunculopontine and/or pontine afferents to the thalamus may precipitate hemidystonia.

Toxicity and detoxification of lipid-derived aldehydes in cultured retinal pigmented epithelial cells

Age-related macular degeneration (ARMD) is the leading cause of blindness in the developed world and yet its pathogenesis remains poorly understood. Retina has high levels of polyunsaturated fatty acids (PUFAs) and functions under conditions of oxidative stress. To investigate whether peroxidative products of PUFAs induce apoptosis in retinal pigmented epithelial (RPE) cells and possibly contribute to ARMD, human retinal pigmented epithelial cells (ARPE-19) were exposed to micromolar concentrations of H2O2, 4-hydroxynonenal (HNE) and 4-hydroxyhexenal (HHE). A concentration- and time-dependent increase in H2O2-, HNE-, and HHE-induced apoptosis was observed when monitored by quantifying DNA fragmentation as determined by ELISA, flow cytometry, and Hoechst staining. The broad-spectrum inhibitor of apoptosis Z-VAD inhibited apoptosis. Treatment of RPE cells with a thionein peptide prior to exposure to H2O2 or HNE reduced the formation of protein-HNE adducts as well as alteration in mitochondrial membrane potential and apoptosis. Using 3H-HNE, various metabolic pathways to detoxify HNE by ARPE-19 cells were studied. The metabolites were separated by HPLC and characterized by ElectroSpray Ionization-Mass Spectrometry (ESI-MS) and gas chromatography-MS. Three main metabolic routes of HNE detoxification were detected: (1) conjugation with glutathione (GSH) to form GS-HNE, catalyzed by glutathione-S-transferase (GST), (2) reduction of GS-HNE catalyzed by aldose reductase, and (3) oxidation of HNE catalyzed by aldehyde dehydrogenase (ALDH). Preventing HNE formation by a combined strategy of antioxidants, scavenging HNE by thionein peptide, and inhibiting apoptosis by caspase inhibitors may offer a potential therapy to limit retinal degeneration in ARMD.

Overriding fifth finger: an unusual sign in lower brachial plexopathy

Hand deformities are often useful clinical signs. To our knowledge, they have not been described in association with brachial plexus lesions. A 28-year-old female presented with sudden left shoulder pain and medial forearm parasthesia. Examination showed the left fifth finger adducting and flexing over the dorsal aspect of the fourth finger. Neurophysiological studies and MRI supported a brachial plexus lesion. The physical sign was not present 5 months post onset and the patient experienced near complete clinical improvement. The unusual physical sign occurred in association with neuralgic amyotrophy. Its occurrence can be explained in terms of transient patchy involvement of nerve fascicles in the brachial plexus.

Audit of diagnostic and interventional craniocervical catheter angiographic procedures at the Singapore General Hospital

INTRODUCTION

Catheter angiography is an established imaging modality of evaluating cerebral and head and neck vascular diseases. It is, however, an invasive procedure with a small risk of complications. The aim of our study was to evaluate the prevalence of peri-procedural complications in a local hospital setting.

MATERIALS AND METHODS

A total of 88 patients underwent diagnostic and interventional craniocervical procedures over 6 months in our department. The casenotes of 83 patients were retrospectively reviewed for complications arising from a total of 99 procedures carried out.

RESULTS

A new focal neurological deficit developed in 3 different patients after a procedure, giving a prevalence of 3.0%. All these occurred in diagnostic procedures and were permanent deficits with correlative computed tomography (CT) or magnetic resonance (MR) imaging findings of acute cerebral infarction. All these occurred in high-risk patients who had severe underlying cerebrocarotid vascular compromise. There was 1 case of contrast medium-induced nephropathy (1.0%), occurring in a patient with pre-existing renal impairment. Local complications included 1 case of iatrogenic external iliac artery dissection (1.0%) and 5 cases (5.1%) of small and uncomplicated puncture site groin haematomas.

CONCLUSION

The most significant complication associated with a craniocervical angiographic procedure was the development of post-procedural stroke in patients with significant preexisting cerebrocarotid vascular compromise. In the absence of this risk factor, craniocervical catheter angiography is a relatively safe procedure.

Case reports of two biopsy-proven patients with Creutzfeldt-Jakob disease in Singapore

INTRODUCTION

Creutzfeldt-Jakob disease (CJD) is the most common transmissible human subacute spongiform encephalopathy. There is limited literature on CJD in Southeast Asia. We describe the clinical course and diagnostic evaluation of 2 Singapore patients with biopsy-proven CJD.

CLINICAL PICTURE

Two patients presented with non-specific symptoms such as withdrawal, forgetfulness, asthenia, giddiness and insomnia. Both patients had spontaneous myoclonic jerks and impairment of multiple neurologic systems (visual, pyramidal, cerebellar and neurocognitive systems). Magnetic resonance imaging and electroencephalography provided helpful supportive evidence. Diagnosis of CJD was established on brain biopsy. Histological features included spongioform degeneration, neuronal cell loss and astrocytosis.

TREATMENT/OUTCOME

Treatment remains palliative. Deterioration in their clinical condition was relentless, progressing to a totally dependent state within 10 to 12 months.

CONCLUSION

The early features of CJD can be varied and non-specific. It is important for physicians from different specialties to be cognisant of the clinical manifestations of CJD and the appearance of supportive and definitive investigations.

Treating childhood acute myeloid leukaemia with the AML-BFM-83 protocol: experience in a developing country

Treatment for childhood acute myeloid leukaemia (AML) consists of remission induction chemotherapy followed by postremission chemotherapy with or without bone marrow transplantation. The AML Berlin-Frankfurt-Munster (BFM)-83 protocol with induction-consolidation-maintenance chemotherapy for 2 years has been reported to result in a 6-year event-free survival (EFS) and event-free interval (EFI) of 49% and 61% respectively. A total of 174 Malaysian children were treated with this protocol between 1985 and 1999. The 5-year EFS and EFI was 30.7% and 48.0% respectively. The overall mortality from sepsis was 24%, which needs urgent address. The 5-year EFS for patients treated before 1993 and after 1993 was 18.6% and 41.3%, respectively (P = 0.04), while the EFI was 32% and 60.6% respectively (P = 0.034). The improvement seen after 1993 was related to a reduction in induction deaths for that period and probably reflected increased capability and familiarity to cope with the demands of the AML-BFM-83 protocol and accompanying complications in the treatment of AML.

Fragile X premutation alleles in SCA, ET, and parkinsonism in an Asian cohort

Among 367 subjects, the authors analyzed 167 patients with essential tremor, sporadic progressive cerebellar ataxia, multiple-system atrophy, and atypical parkinsonism and 200 healthy control subjects for FMR1 premutation alleles. None of the subjects carried alleles within the premutation range. These findings suggest that in the absence of other supportive clinical or imaging features, the cost-effectiveness of routine fragile X tremor/ataxia syndrome screening in this Asian cohort with movement disorders was low.

Clinico-radiologic correlation in unilateral and bilateral hemifacial spasm

INTRODUCTION

Bilateral hemifacial spasm (HFS) is rare. Clinico-radiologic correlates utilizing advanced imaging techniques have not been systematically examined in bilateral HFS. The prevalence of bilateral HFS in an Asian population has not been clarified.

OBJECTIVES

We examined the prevalence and clinico-radiologic correlates of bilateral HFS in a clinic-based cohort and compared the clinical characteristics of unilateral HFS patients with and without contralateral neurovascular contact (NVC) in HFS.

METHODS

Patients clinically diagnosed with HFS were examined for bilateral symptoms. Imaging analysis involved the utilization of reformatted, multi-planar three-dimensional time-of-flight magnetic resonance angiography (3D-TOF MRA), and constructive interference at steady state (CISS-MR) sequences. The clinical and imaging data was compared between HFS with and without NVC.

RESULTS

Amongst 162 consecutive HFS patients, 2 (1.6%) had bilateral symptoms. Both patients had unilateral onset followed by bilateral and asynchronous facial contractions. The contralateral side of the face began to twitch at a mean of 1.5 years later. MRI/A revealed significant NVC of the root exit zone (REZ) of the facial nerve on the ipsilateral side with mild NVC contralaterally. The degree of NVC correlated with the clinical severity of the patients' symptoms. MRI/A analysis of 40 HFS patients with unilateral symptoms demonstrated NVC on the contralateral side in six patients (15%). The mean age and duration of symptoms were not different between HFS patients with and without contralateral NVC.

CONCLUSIONS

We demonstrated clinico-radiologic correlation between the clinical severity and the degree of NVC at the REZ of the facial nerve in bilateral HFS. Amongst unilateral HFS, there was no significant difference clinically between those with and without contralateral NVC. The low 1.6% prevalence of bilateral HFS in our Asian cohort was compatible with the rare prevalence in other ethnic populations.

Systematic correlation of transcranial magnetic stimulation and magnetic resonance imaging in cervical spondylotic myelopathy

STUDY DESIGN

A prospective study over a 3.5-year period involving transcranial magnetic stimulation and magnetic resonance imaging.

OBJECTIVES

To assess the correlation of transcranial magnetic stimulation and magnetic resonance imaging in cervical spondylotic myelopathy qualitatively and statistically.

SUMMARY OF BACKGROUND DATA

Cervical spondylotic myelopathy presents with different degrees of cord compression, which can be assessed by magnetic resonance imaging. There are no large studies correlating transcranial magnetic stimulation and magnetic resonance imaging findings in this condition.

METHODS

A total of 141 patients with a clinical diagnosis of cervical spondylotic myelopathy were prospectively studied over a 3.5-year period. They were classified into Groups 1 to 4 based on severity of cervical cord changes on magnetic resonance imaging. All had transcranial magnetic stimulation and central motor conduction time measurements within 2 months of the magnetic resonance imaging study.

RESULTS

Twenty-eight, 49, 28, and 36 patients were classified into Groups 1 to 4, respectively. Mean upper limb and lower limb central motor conduction times correlated with the severity of magnetic resonance cord compression. The absence of central motor conduction time abnormalities correlated reliably with the absence of cervical cord impingement as in Group 1. Statistically significant right left difference in central motor conduction time in the lower limbs was seen between Groups 1 (no cord changes) and Group 2 (mild cord impingement). Eight other patients with diagnoses other than cervical spondylotic myelopathy all showed central motor conduction time abnormalities. The sensitivity and specificity for transcranial magnetic stimulation for differentiating the presence from absence of magnetic resonance imaging cord abnormality were 100% and 84.8%, respectively.

CONCLUSIONS

Transcranial magnetic stimulation showed excellent correlation with magnetic resonance imaging findings and can be considered as an effective technique for screening patients for cervical cord abnormalities before magnetic resonance imaging in the clinical setting. The findings in this study have relevant implications in the pathophysiology, management, and health costs of cervical spondylotic myelopathy.

Acute ophthalmoparesis in the anti-GQ1b antibody syndrome: electrophysiological evidence of neuromuscular transmission defect in the orbicularis oculi

OBJECTIVE

To prospectively study anti-GQ1b antibody positive cases of acute ophthalmoparesis (AO) clinically and electrophysiologically.

METHODS

Nine consecutive cases presenting with predominantly acute ophthalmoplegia were assessed clinically and had stimulated single fibre electromyography (SFEMG) of the orbicularis oculi at presentation. All had magnetic resonance imaging brain scans and anti-GQ1b antibody titres determined.

RESULTS

Four cases had elevated anti-GQ1b antibody titres and abnormal SFEMG studies, which improved in tandem with clinical recovery over three months. Five other anti-GQ1b antibody negative cases were diagnosed as diabetic related cranial neuropathy, idiopathic cranial neuropathy, ocular myasthenia gravis, and Tolosa-Hunt syndrome. All five cases showed complete recovery over a three month period.

CONCLUSIONS

This study demonstrated electrophysiologically the dynamic improvement of neuromuscular transmission of anti-GQ1b antibody positive cases of AO, in tandem with clinical recovery. SFEMG is of value in differentiating weakness due to neuromuscular transmission defect from neuropathy in these clinical situations.

Monophasic, solitary tumefactive demyelinating lesion: neuroimaging features and neuropathological diagnosis

The characteristic clinicoradiological findings of multiple sclerosis and acute disseminated encephalomyelitis (ADEM), demonstrating a recurrent progressive course in the former and monophasicity in the latter associated with multiple discrete white matter lesions with variable enhancement on MRI, are not a diagnostic challenge. On the other hand, the less typical radiological presentation of a solitary tumefactive demyelinating lesion mimics a neoplasm, and often necessitates a biopsy. Nonetheless, histopathological examination is an imperfect gold standard and the recognition of certain imaging features may facilitate the correct diagnosis.

Levodopa-induced oromandibular dystonia in progressive supranuclear palsy

Levodopa-induced dyskinesias have been reported in Parkinson's disease and multiple system atrophy. Cranial dystonias are rare in patients with progressive supranuclear palsy (PSP). In this report we describe an unusual case of reversible levodopa-induced Oromandibular dystonia (OMD) in a PSP patient to highlight the importance of recognizing this drug related complication in the management of PSP, and discuss the possible underlying pathophysiology.

Evolving spectrum of movement disorders in extrapontine and central pontine myelinolysis

Extrapontine (EPM) and central pontine myelinolysis (CPM) are rare and frequently related to rapid correction of hyponatremia. We describe a 60-year-old woman who developed an unusual evolving spectrum of movement disorders secondary to EPM and CPM following intravenous sodium replacement therapy for severe hyponatremia. She presented initially with confusion, generalized coarse postural limb tremor, myoclonic jerks and quadriparesis. Subsequently her mental state improved and her tremor and weakness resolved. Over the following months, she developed progressive painful dystonia of her facial musculature and lower limbs. This gradually became generalized and associated with choreoathethosis in her limbs. In addition, she had increasing bradykinesia and rigidity, which responded poorly to levodopa treatment. Our case illustrates that while the myelin destruction occurs during the initial insult of the osmotic demyelinating process, its delayed clinical effects resulting from ineffective reorganization of neuronal structures may be progressive, evolve with time, and difficult to treat.

Neurological changes following radiation therapy for head and neck tumours

Radiation therapy is widely used in the treatment of head and neck tumours either as a primary form of treatment or a supplementary modality. Although the benefits of radiation therapy are well established, this treatment modality is not without untoward consequences and complications. The intent of this paper is to highlight the neurological complications that may follow the treatment for head and neck malignancies, in particular, following radiation therapy for nasopharyngeal carcinoma.