Progression from selective to general involvement of hippocampal subfields in schizophrenia.

Volume deficits of the hippocampus in schizophrenia have been consistently reported. However, the hippocampus is anatomically heterogeneous; it remains unclear whether certain portions of the hippocampus are affected more than others in schizophrenia. In this study, we aimed to determine whether volume deficits in schizophrenia are confined to specific subfields of the hippocampus and to measure the subfield volume trajectories over the course of the illness. Magnetic resonance imaging scans were obtained from Data set 1: 155 patients with schizophrenia (mean duration of illness of 7 years) and 79 healthy controls, and Data set 2: an independent cohort of 46 schizophrenia patients (mean duration of illness of 18 years) and 46 healthy controls. In addition, follow-up scans were collected for a subset of Data set 1. A novel, automated method based on an atlas constructed from ultra-high resolution, post-mortem hippocampal tissue was used to label seven hippocampal subfields. Significant cross-sectional volume deficits in the CA1, but not of the other subfields, were found in the schizophrenia patients of Data set 1. However, diffuse cross-sectional volume deficits across all subfields were found in the more chronic and ill schizophrenia patients of Data set 2. Consistent with this pattern, the longitudinal analysis of Data set 1 revealed progressive illness-related volume loss (~2-6% per year) that extended beyond CA1 to all of the other subfields. This decline in volume correlated with symptomatic worsening. Overall, these findings provide converging evidence for early atrophy of CA1 in schizophrenia, with extension to other hippocampal subfields and accompanying clinical sequelae over time.

Progression of subcortical atrophy in mild Parkinson's disease and its impact on cognition.

BACKGROUND AND PURPOSE: Mild cognitive impairment (MCI) is associated with pronounced grey matter atrophy in various brain regions. However, the association between atrophy patterns and progression from no cognitive impairment (NCI) to Parkinson's disease (PD)-MCI is not clearly known. We investigated the pattern and progression of atrophy in subcortical structures and its impact on cognition in patients with mild PD. METHODS: Sixty-five patients with mild PD with baseline and longitudinal clinical and neuropsychological assessments, and structural magnetic resonance imaging scans were studied. Movement Disorder Society Task Force criteria were used to classify patients with PD into PD-NCI (n = 54) and PD-MCI (n = 11). Based on progression over time, those who remained without cognitive impairment were classified as PD-stable (n = 42) and those who converted to MCI over 18 months were classified as PD-converters (n = 12). FreeSurfer was used to measure cortical thickness and subcortical volumes at baseline and follow-up. RESULTS: Parkinson's disease-MCI showed baseline thalamus atrophy and progressive atrophy in the thalamus, caudate, presubiculum, cornu ammonis 1 and 2-3, and significant memory and executive dysfunction compared with PD-NCI. PD-converters had greater accumbens atrophy at baseline and progressive atrophy in the thalamus, caudate and accumbens with dysfunctions in memory and executive domains. CONCLUSIONS: Progression of cognitive impairment in non-demented PD is associated with a specific pattern of subcortical atrophy. Findings from this study will allow future studies to investigate in the role of subcortical structures as a biomarker for PD dementia.

Ministry of health clinical practice guidelines: dementia.

The Ministry of Health (MOH) has updated the clinical practice guidelines on Dementia to provide doctors and patients in Singapore with evidence-based treatment for dementia. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the MOH clinical practice guidelines on Dementia, 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/healthprofessionalsportal/doctors/guidelines/cpg_medical/2013/cpgmed_dementia_revised.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.

Post-stroke subjective cognitive impairment is associated with acute lacunar infarcts in the basal ganglia.

BACKGROUND AND PURPOSE: While recent studies have examined neuroimaging correlates of post-stroke mild cognitive impairment (MCI), no studies have examined neuroimaging correlates of post-stroke subjective cognitive impairment (SCI). METHODS: Consecutive patients with magnetic resonance imaging-confirmed acute lacunar strokes at a tertiary institute were recruited for this cross-sectional study. All patients underwent cognitive testing, and those with MCI were excluded from these analyses. Two independent neuroradiologists ascertained data on the number and location of any infarcts, as well as the degree of white matter hyperintensities. Multivariate logistic regression analyses were performed to study the association between neuroimaging markers and SCI. Only variables that were significant in the univariate stage and clinically relevant potential confounders were included in multivariable analyses. RESULTS: Of 145 patients evaluated, 48 patients with MCI were excluded from the study. Of the remaining 97 patients, 30 patients had SCI. In multivariable analyses, only mini-mental state examination (OR 0.61; CI 0.38-0.98) and basal ganglia infarcts (OR 8.19; CI 1.18-56.6) were significant predictors of SCI. CONCLUSION: In patients with acute lacunar strokes, we find that basal ganglia infarcts are associated with SCI. As the basal ganglia have been previously shown to be involved with learning of tasks, we hypothesize that infarcts in basal ganglia may affect learning speeds thereby contributing to the development of SCI. Larger studies are needed to confirm these results.

Serum albumin and hemoglobin are associated with physical function in community-living older persons in Singapore.

OBJECTIVES: Albumin and hemoglobin are viewed as markers of nutritional and inflammatory status. This study examined the associations of serum albumin and hemoglobin with physical function in community-living older adults. DESIGN: Population-based cross-sectional and longitudinal study. SETTING: The Singapore Longitudinal Aging Studies (SLAS), a community-based study in urban Singapore. PARTICIPANTS: 2762 older adults aged 55 and above assessed at baseline, and 1829 at follow up 1-2 years later. MEASUREMENTS: Serum albumin and hemoglobin, Performance Oriented Mobility Assessment (POMA), knee extension strength at baseline, and Instrumental Activities of Daily Living (IADL) at baseline and follow up. RESULTS: In cross-sectional multivariate analyses that adjusted for haemoglobin and other confounders, albumin showed a significant linear association (p<0.001) with POMA balance score (b=0.06, SE=0.02) and knee extension strength (b=0.70, SE=0.10). Independently of albumin, hemoglobin also showed a significant linear association with POMA balance score (b=0.09, SE=0.04). In longitudinal analyses, albumin was significantly associated with IADL decline (IADL total score drop>=1 during follow-up), OR= 0.92 (0.87 - 0.97), p=<0.01. CONCLUSION: The findings suggest that low levels of albumin and hemoglobin are potentially useful risk markers of physical functional decline in older adults. Further research should investigate whether improvements in the levels of albumin and hemoglobin alter the level of functional disability and risk of functional decline.

Health Promotion Board-Ministry of Health clinical practice guidelines: functional screening for older adults in the community.

The Health Promotion Board (HPB) and the Ministry of Health (MOH) publish clinical practice guidelines to provide doctors and patients in Singapore with evidence-based guidance on managing important medical conditions. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the HPB-MOH clinical practice guidelines on Functional Screening for Older Adults in the Community, 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 Health Promotion Board website (http://www.hpb.gov.sg/uploadedFiles/HPB_Online/Publications/CPGFunctionalscreening.pdf). 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.

MR Tractography in Horizontal Gaze Palsy and Progressive Scoliosis. A Case Report.

Congenital brainstem malformation without associated cerebellar disorder is uncommon. Horizontal gaze palsy with progressive scoliosis is one such rare syndrome with brainstem hypoplasia without any disorder of the cerebellum. It has an autosomal recessive inheritance and is characterised by absent horizontal gaze and severe progressive scoliosis from birth. We describe a 58-year-old man with horizontal gaze palsy and severe thoracolumbar scoliosis with typical MR imaging findings of brainstem hypoplasia, and MR tractography confirmation of complete absence of decussation of the pyramidal tract fibers.

Surgical planning for microsurgical excision of cerebral arterio-venous malformations using virtual reality technology.

BACKGROUND: To evaluate the feasibility of surgical planning using a virtual reality platform workstation in the treatment of cerebral arterio-venous malformations (AVMs) METHODS: Patient-specific data of multiple imaging modalities were co-registered, fused and displayed as a 3D stereoscopic object on the Dextroscope, a virtual reality surgical planning platform. This system allows for manipulation of 3D data and for the user to evaluate and appreciate the angio-architecture of the nidus with regards to position and spatial relationships of critical feeders and draining veins. We evaluated the ability of the Dextroscope to influence surgical planning by providing a better understanding of the angio-architecture as well as its impact on the surgeon's pre- and intra-operative confidence and ability to tackle these lesions. FINDINGS: Twenty four patients were studied. The mean age was 29.65 years. Following pre-surgical planning on the Dextroscope, 23 patients underwent microsurgical resection after pre-surgical virtual reality planning, during which all had documented complete resection of the AVM. Planning on the virtual reality platform allowed for identification of critical feeders and draining vessels in all patients. The appreciation of the complex patient specific angio-architecture to establish a surgical plan was found to be invaluable in the conduct of the procedure and was found to enhance the surgeon's confidence significantly. CONCLUSION: Surgical planning of resection of an AVM with a virtual reality system allowed detailed and comprehensive analysis of 3D multi-modality imaging data and, in our experience, proved very helpful in establishing a good surgical strategy, enhancing intra-operative spatial orientation and increasing surgeon's confidence.

Virchow-robin spaces in health and disease.

Virchow-Robin spaces are pial-lined, interstitial fluid-filled structures that do not directly communicate with the subarachnoid space, and accompany penetrating arteries and veins. They are common, incidental, "leave me alone" lesions that should not be mistaken for more ominous disease. They are frequently seen in the supratentorial white matter, basal ganglia region, around the anterior commissure, and surrounding penetrating lenticulostriate arteries, thalamus, midbrain, cerebellum, insular cortex, corpus callosum, cingulate gyrus, extreme capsule, along the optical tracts, and in the hippocampus. Most are small, well-defined fluid-filled cysts less than five mm in diameter, and are isointense to CSF on all pulse sequences. They are often mistaken for lacunar infarcts, cystic neoplasms or infectious cysts. We retrospectively analyzed various appearances of VRS as seen on magnetic resonance imaging of brain in 100 cases, in an attempt to provide a better understanding of these lesions and their significance in various physiological and pathological conditions.

Clinics in diagnostic imaging (120). Right rhinogenic optic neuritis secondary to mucocoele of the Onodi cell.

Acute visual loss can be caused by retrobulbar optic neuritis, radiation optic neuropathy or ischaemic optic neuropathy. Sinusitis affecting the Onodi cell, a posterior ethmoidal air cell that has encroached on the adjacent sphenoid bone forming the optic canal, can present rarely with visual loss. We report a 60-year-old man, who developed a sudden ache on the nasal aspect of his right eye, and deterioration of the vision in his right eye. This case illustrates the typical radiological appearances of the Onodi cell on MR imaging and CT. The diagnosis of right rhinogenic optic neuritis secondary to mucocoele of the Onodi cell was confirmed at surgery. Functional endoscopic sinus surgery with decompression of the Onodi cell was performed. Physicians should be familiar with the presentation, performed. Physicians should be familiar with the presentation, diagnosis and management of this rare but important condition.

Validation of three-dimensional laser scanning for the assessment of facial fat changes.

OBJECTIVE: We aimed to evaluate the accuracy of three-dimensional laser scanning as an objective method for detecting facial changes. METHODS: Facial laser scanning was performed at baseline and repeated after a median of 10 months in 24 HIV-infected patients, 12 with ongoing lipodystrophy, five with >10% weight loss and seven with >10% weight gain. Surface volume change was estimated using a standardized technique, and compared with change in cheek fat measured by magnetic resonance imaging (MRI). RESULTS: The median laser scanning surface volume changes were -2.1 (range -4.6 to -0.8) mL in the lipoatrophy group, -1.5 (range -6.8 to -1.3) mL in the weight loss group and +3.1 (range -0.2 to +5.4) mL in the weight gain group (the median MRI cheek fat changes were -4.6, -3.7 and +7.0 mL in the three groups, respectively). Laser scanning and MRI measurements were not significantly associated in lipoatrophy patients (r=0.34, P=0.28), but there was a good association in patients who changed weight (r=0.71, P=0.01). CONCLUSIONS: Laser scanning detects changes in the appropriate direction, although it underestimates MRI-measured cheek fat changes. Laser scanning may be useful as an objective measure of cheek surface volume changes, but needs further validation in larger clinical cohorts.

Diffusion tensor imaging in a symptomatic patient with an intra-axial arachnoid cyst.

We present a case of an elderly lady with a symptomatic large intra-axial right frontoparietal arachnoid cyst displacing the corticospinal tract (CST) posteromedially on diffusion tensor imaging. This information assisted the surgeons in confirming the symptomatic nature of the lesion, in planning an appropriate surgical procedure, as well as in prognostication of recovery.

Early experiences with diffusion tensor imaging and magnetic resonance tractography in stroke patients.

INTRODUCTION: Recent advances in magnetic resonance (MR) diffusion tensor imaging technique enable evaluation of the anisotropy of white matter tracts in-vivo, as well as the integrity of fibre tracts and their orientation. We describe our initial experiences with diffusion tensor imaging and MR tractography techniques to evaluate the structural degeneration of white matter tracts following stroke. METHODS: Diffusion tensor imaging data were acquired in 11 cases with stroke on a 3T MR imaging scanner, with three-dimensional diffusion tensor imaging-based colour maps and MR tractography performed offline. We evaluated the spatial relationships of the eloquent white matter tracts to the infarcts and areas of haemorrhage, and classified therewith the tracts as either disrupted or displaced. We compared these with the clinical severity of the neurological deficits and prognosis. RESULTS: A good correlation was found between tractography findings and patient's clinical recovery. All the patients with disruption of white matter tracts had residual deficits on clinical follow-up, whereas the patients with displaced tracts had near complete neurological recovery. CONCLUSION: Diffusion tensor imaging and MR tractography provide a novel and useful method to directly visualise changes in the white matter tracts in stroke. This can potentially allow clinical-imaging correlation with prognostic potential.

Classification of gait patterns in the time-frequency domain.

This paper describes the classification of gait patterns among descending stairs, ascending stairs and level walking activities using accelerometers arranged in antero-posterior and vertical direction on the shoulder of a garment. Gait patterns in continuous accelerometer records were classified in two steps. In the first step, direct spatial correlation of discrete dyadic wavelet coefficients was applied to separate the segments of gait patterns in the continuous accelerometer record. Compared to the reference system, averaged absolute error 0.387 s for ascending stairs and 0.404 s for descending stairs were achieved. The overall sensitivity and specificity of ascending stairs were 98.79% and 99.52%, and those of descending stairs were 97.35% and 99.62%. In the second step, powers of wavelet coefficients of 2 s time duration from separated segments of vertical and antero-posterior acceleration signals were used as features in classification. Our results proved a reliable technique of measuring gait patterns during physical activity.

Reversible splenial lesion in clinically mild encephalitis.

Clinically mild encephalitis with a reversible lesion in the central splenium of the corpus callosum (SCC) is a recently-described clinicoradiological entity. We report a 20-year-old man presenting with fever and a single episode of generalised seizures. Initial magnetic resonance (MR) images showed an ovoid lesion with T1 and T2 signal prolongation, restricted diffusion and decreased apparent diffusion coefficient values in the centre of the SCC, which resolved completely on a repeat MR imaging done three months later. Clinically, the patient had a mild clinical course and made a full recovery. This clinicoradiological entity with an excellent prognosis is elaborated with possible differential diagnoses given. Emphasis is placed on avoiding unnecessary invasive investigation or therapeutic intervention.

Hippocampal involvement in dengue fever.

Flaviviruses are among the most important emerging viruses known to man. Dengue is the most common flavivirus infection in Singapore, and is transmitted between humans by the Aedes mosquito. We report a 25-year-old man with dengue fever complicated by selective hippocampal involvement manifesting as amnesia. This has not been described in the literature previously. Dengue polymerase chain reaction and serology were positive. Magnetic resonance imaging of the brain showed bilateral hippocampal involvement.

Normal variants of the intracranial circulation demonstrated by MR angiography at 3T.

Magnetic resonance angiography (MRA) at 3T offers increased signal to noise ratio with better background suppression, leading to exquisite depiction of the intracranial circulation. We present a pictorial review of the normal variations and anomalies of the intracranial circulation detected on MRA performed on a high field 3T clinical scanner using parallel imaging techniques. The salient imaging features of these anomalies and normal variations are discussed with relevance to clinical practice.

The relationship between postoperative complications and outcomes after hip fracture surgery.

INTRODUCTION: We studied the prevalence of postoperative complications in a series of consecutive patients who received surgery for hip fractures in a major public hospital in Singapore. We also studied the predictors for the occurrence of complications and the impact of these complications on patient outcomes. MATERIALS AND METHODS: A retrospective chart review of patients admitted with hip fracture, from March to November 2001, was carried out. Patients were classified as having postoperative complications if they developed any of the following conditions after surgery: dislocation of prosthesis, deep vein thrombosis, postoperative confusion, foot drop, stroke, cardiac arrhythmias or acute myocardial infarctions, urinary retention, urinary tract infection, pneumonia, wound infection and incident pressure sores. RESULTS: Of the 180 patients studied, 60 developed postoperative complications. Significant predictors of complications after logistic regression included being of female gender [odds ratio (OR), 2.79; 95% confidence interval (CI), 1.13 to 6.89] and pre-fracture mobility status (OR for independent ambulators 0.45; 95% CI, 0.23 to 0.87), but not the age of the patients. Postoperative complications significantly affected the length of stay within the acute hospital (beta coefficient, 6.42; 95% CI, 2.55 to 10.29), but were not associated with a decline in mobility status at 3 months post-fracture, eventual discharge destination or readmission within 1 year. CONCLUSION: Postoperative complications are common after surgery for hip fractures and result in significantly longer hospitalisation periods. Significant predictors for such complications include being of female gender and pre-fracture mobility. Age, in itself, does not result in a higher risk of complications and should not preclude older hip fracture patients from surgical management.

A multivariate regression model predicted falls in residents living in intermediate hostel care.

BACKGROUND AND OBJECTIVE: To evaluate whether individual falls risk could be predicted in a frail elderly population. STUDY DESIGN AND SETTING: We developed and tested an assessment tool and falls risk score for predicting falls based on a multivariate regression model in a prospective cohort study of intermediate care residents. RESULTS: During the follow-up period, 1,736 falls by 1,107 subjects were recorded with an average of 170 falls per 100 person-years. Fifty percent of the study population had at least one fall within a year. Significant independent risk factors were poor balance, cognitive impairment, incontinence, higher illness severity rating, and older age. Twenty-two percent of participants with a falls risk score > or =7 accounted for 42% of the total falls, with a falls rate of 317 per 100 person-years. This rate was a sixfold increase from the falls rate of 52 per 100 person-years observed in participants with a score < 3. A high score (> or =7) indicated almost a 2 in 3 chance of falling, while a low score (<3) indicated approximately a 1 in 7 chance of falling within 6 months. CONCLUSION: The assessment tool and falls risk score could identify individuals in this frail elderly population at high risk of falls.

Determinants of health-related quality of life in institutionalised older persons in northern Sydney.

It is recognised that the focus of health-care interventions for frail older persons should not be restricted to increasing longevity, but should encompass measures aimed at improving or maintaining the health-related quality of life (HRQoL) of these individuals. We studied the HRQoL profile of 612 frail older persons residing in nursing homes and hostels in northern Sydney, Australia, and sought to ascertain some of the factors that affect their perceived quality of life. Our findings suggest that common health states that may cause loss of independence and dignity (e.g. presence of osteoarthritis, presence of urinary incontinence, previous fracture, Parkinson's Disease and increasing frailty as reflected by residence in nursing homes) are strongly, and independently, associated with the HRQoL of institutionalised older persons. Some of these conditions may be amenable to intervention.