A study of Clinico-Neuroradiologic Correlation in Patients with Dementia

INTRODUCTION: Dementia is characterized by decline in the cognitive functioning of an individual that significantly affects the quality of life and intrudes into the activity of daily living. The prevalence of dementia is increasing and is on the rise. This is due to the increased longevity that has resulted in increasing proportions of elderly population in whom the prevalence of dementia is higher. Dementia is defined by the DSM 5 criteria as decline from previously established baseline in the at least one of the cognitive domains: Memory and learning, executive function, language, complex attention, social cognition and perceptual motor function and it affects the activities of daily living. The symptoms in these patients do not occur exclusively during delirium and are not explainable by psychiatric disorder. AIM OF THE STUDY: To study the association between clinical deficits in cognitive domains of attention, memory and language in subjects with dementia and the neuroimaging correlates of the corresponding networks. OBJECTIVES: 1. To evaluate clinical deficits in cognitive domains of attention, memory and language in subjects with dementia. 2. To study the neuroimaging findings in subjects of Dementia on MR voxel based morphometry, MR diffusion tensor imaging and 18-Fluorodeoxyglucose Positron Emission Tomography in corresponding networks of attention, language and memory respectively. 3. To determine neuroimaging correlates of deficits in attention, language and memory in subjects with dementia in corresponding networks of attention, language and memory respectively. MATERIALS AND METHODS: Subjects attending dementia and cognitive neurosciences clinic at Rajiv Gandhi Government General Hospital, Chennai (RGGGH) were enrolled in the study. A total of 60 patients and 30 controls were recruited for the study. All the subjects were well informed about the study and the consent forms were obtained prior to the assessments. All the patients in the study underwent clinical examination for establishing the diagnosis of dementia. After the clinical assessment the subjects under investigation underwent four different types of assessments. The assessments include neuropsychological assessments, Voxel based Morphometry, Diffusion Tensor Imaging (for both controls and cases), and FDG-PET (for cases alone). METHODOLOGY: A random sample of 60 patients and 30 age-gender matched controls were selected from dementia and cognitive neurosciences clinic at Rajiv Gandhi Government General Hospital(RGGGH), Chennai during Dec. 2014 – Feb. 2018. The study was approved by Institutional Ethical Committee of Rajiv Gandhi Government General Hospital, Chennai. Neuropsychological tests were performed after obtaining consents from the subjects or caretakers. Patients were selected on the basis of MoCA scores where a case with a MoCA score of below 27 and satisfying the inclusion/exclusion criteria has been treated as a patient and included in the present study. The following clinical assessments were made on each patient: Addenbrooke‘s Cognitive Examination III (ACE III), Wechsler‘s Memory Scale (WMS), Trail Making Test A & B (TMT), Auditory Verbal Learning Test (AVLT) and scores were assessed accordingly. Neuropsychological aspects of both patients and controls were assessed by a single trained clinical psychologist. RESULTS: Before carrying out the major study, a pilot study was conducted taking a random sample of 10 patients and 10 controls. Reliability and validity of the protocols used for carrying out the major study were computed using appropriate statistical tools such as Cronbach‘s alpha for reliability and expert opinion on the validity of the protocols. Reliability analysis was carried out using split half method and the Cronbach alpha for part 1 of the protocol was obtained as 0.913 and for part 2 it was 0.993. The overall reliability of the protocol was 0.937 indicating high reliability of the test schedule used in the present study. CONCLUSIONS: Patients and controls were well differentiated in all the neuro-psychological parameters, MoCA, Addenbrook‘s Cognitive Score, WMS, AVLT, Digit Span, Story Recall, and Complex figure. Patients are found to have low scores in all these aspects compared to controls. Stepwise regression analysis indicates scores in only five parameters, namely attention, memory, AVLT, Digit span, and complex figure are enough to classify a person as having dementia or a normal person with a prediction accuracy of nearly 99 per cent. All these neuro psychological parameters are interrelated to one another. Inter correlations of neuro psychological parameters are very high among patients compared to controls in the present study. Analysis of Diffusion Tensor Imaging indicates that the white matter tract, Superior Longitudinal Fasciculus does not play any major role in attention and language domain. In contrast, Fornix has a major role to play in the memory domain. All the metrics of DTI show significant difference between patients and controls in the white matter tract Fornix on either side of the brain. As far as the DTI metrics are concerned, all the metrics have the same levels on both sides of brain of patients and controls. In most of the white matter tracts, the metrics, RD, MD, and AD are found to be high among patients compared to controls. FA is found to be low among patients in white matter tracts like IFO and Fornix. The analysis of diffusion metrics suggests the varying involvement of the white matter fasciculi of the respective domains. Analysis of FDG PET data indicates that about 70 per cent to 93 per cent of patients have hypometabolism in all the five cortical areas of attention domain- frontal association, posterior cingulate, parietal association, anterior cingulate, and caudate regions on either side of brain. Similarly 77 to 91 per cent of patients have hypometabolism in cortical areas of language domain, frontal association, temporal association and parietal association regions on either side of brain. About 85 to 89 per cent of patients have hypometabolism on either side of anterior cingulate regions. Voxel based Morphometry analysis clearly indicated that the patients and controls are significantly different in the following gray matter hubs of Attention Network : Dorsolateral Prefrontal Cortex, Frontal Eye Field, Occipital Eye Field, Cingulate Cortex and Superior Parietal Lobule. Similar scenario is seen in gray matter hubs of language Network: Broca's Area, Wernicke's Area, and Geschwind‘s Area (Inferior Parietal Lobule). In gray matter hubs of Memory Network: Uncus, Hippocampus, and Nucleus Accumbens areas, patients are found to be significantly different from the controls

Vanishing headache in a young female: An interesting case report

Headache is one of the most common neurological symptom occurring worldwide. Here, we present a unique case of secondary headache in a young female which got reversed with appropriate treatment. A young female who presented with a severe subacute unilateral left-sided intractable headache with papilledema and obstructive hydrocephalus was found to have 4th ventricular neurocysticercosis causing obstruction of the foramen of Magendi and Luschka, relieved on timely surgical excision and with medical management. This case is reported to highlight the rare causes of secondary headache and various presentations of neurocysticercosis, in endemic areas like India as it causes neurological morbidity which can be alleviated on appropriate treatment, thereby preventing economic hardship and improving the quality of life

Unraveling the diverse nature of service quality in a sharing economy: a social exchange theory perspective of Airbnb accommodation

This is an accepted manuscript of an article published by Emerald in International Journal of Contemporary Hospitality Management on 11/09/2017, available online: https://doi.org/10.1108/IJCHM-08-2016-0420 The accepted version of the publication may differ from the final published version.Purpose- This study investigates customers’ perceptions of the service quality facets of Airbnb accommodation using social exchange theory as a suitable conceptual framework to explain aspects of interactivity between guests and hosts. Design/methodology/approach- A self-administered questionnaire consisting of 25 accommodation- specific service quality attributes, structured according to Akbaba’s (2006) measurement scale and based on the service quality hierarchical conceptualization described by Brady and Cronin (2001) and Cronin and Taylor (1992), was distributed to Airbnb international guests visiting Phuket, Thailand. The sample was chosen through a two-stage sampling process and the PLS-SEM technique was used for data analysis. Findings- The results showed that convenience and assurance are critical contributors to the measurement of service quality in remote Airbnb lodgings. The findings further revealed that Airbnb guests are mainly interested in lodgings which have access to certain tourist sights, and in easily accessible information and efficient resolution of problems during their stay. We also found that guests greatly value the convenience and flexibility offered by Airbnb, and that they particularly appreciate the warm hospitality provided by the hosts. Finally, Airbnb guests have very low expectations of the amenities and services available at the lodgings. Research limitations/implications-Airbnb is one of the most well-known examples of hospitality in the sharing economy and results cannot be generalized to similar accommodation providers in sharing economies. Despite the appropriateness of using the measurement tool provided by Akbaba (2006), it is only one option among others for measuring service quality. Practical implications- The current study can assist hosts in gaining better knowledge of guests’ decision making processes and in designing effective marketing strategies by focusing on guests’ requirements in terms of service quality. The effective use of competitive strengths and the prioritization of business resources would potentially enhance guests’ positive experiences at the accommodation and at the destination. Originality/value-Limited numbers of studies have focused on the sharing economy and hospitality and in particular on Airbnb and this is the first study with a focus on service quality issues in terms of Airbnb accommodation

A Study of Clinico Neuroradiologic Correlation in Patients with Dementia

Patients and controls were well differentiated in all the neuro-psychological parameters, MoCA, Addenbrook‘s Cognitive Score, WMS, AVLT, Digit Span, Story Recall, and Complex figure. Patients are found to have low scores in all these aspects compared to controls. Stepwise regression analysis indicates scores in only five parameters, namely attention, memory, AVLT, Digit span, and complex figure are enough to classify a person as having dementia or a normal person with a prediction accuracy of nearly 99 per cent. All these neuro psychological parameters are interrelated to one another. Inter correlations of neuro psychological parameters are very high among patients compared to controls in the present study. Analysis of Diffusion Tensor Imaging indicates that the white matter tract, Superior Longitudinal Fasciculus does not play any major role in attention and language domain. In contrast, Fornix has a major role to play in the memory domain. All the metrics of DTI show significant difference between patients and controls in the white matter tract Fornix on either side of the brain. As far as the DTI metrics are concerned, all the metrics have the same levels on both sides of brain of patients and controls. In most of the white matter tracts, the metrics, RD, MD, and AD are found to be high among patients compared to controls. FA is found to be low among patients in white matter tracts like IFO and Fornix. The analysis of diffusion metrics suggests the varying involvement of the white matter fasciculi of the respective domains. Analysis of FDG PET data indicates that about 70 per cent to 93 per cent of patients have hypometabolism in all the five cortical areas of attention domain- frontal association, posterior cingulate, parietal association, anterior cingulate, and caudate regions on either side of brain. Similarly 77 to 91 per cent of patients have hypometabolism in cortical areas of language domain, frontal association, temporal association and parietal association regions on either side of brain. About 85 to 89 per cent of patients have hypometabolism on either side of anterior cingulate regions. Voxel based Morphometry analysis clearly indicated that the patients and controls are significantly different in the following gray matter hubs of Attention Network :Dorsolateral Prefrontal Cortex, Frontal Eye Field, Occipital Eye Field, Cingulate Cortex and Superior Parietal Lobule. Similar scenario is seen in gray matter hubs of language Network: Broca's Area, Wernicke's Area, and Geschwind‘s Area (Inferior Parietal Lobule). In gray matter hubs of Memory Network: Uncus, Hippocampus, and Nucleus Accumbens areas, patients are found to be significantly different from the controls

Mapping of finite-element grids onto parallel computers using neural networks

In this paper, LSOM (Load-balancing Self-Organizing Map), a neural network based on Kohonen's self-organizing map is proposed for the problem of mapping finite-element method (FEM) grids to distributed-memory parallel computers with mesh interconnection networks. The rough global ordering produced by LSOM is then combined with the local refinement Kernighan-Lin algorithm (called LSOM-KL) to obtain the solution. LSOM-KL obtained a load imbalance of less than 0.1% and a low number of hops, comparable to results obtained with commonly used recursive bisection methods

Quad-LED Complex Modulation (QCM) for Visible Light Wireless Communication

In this paper, we propose a simple and novel complex modulation scheme for multiple-LED wireless communication, termed as quad-LED complex modulation (QCM). The proposed QCM scheme uses four LEDs (hence the name `quad-LED'), one LED each to map positive real, negative real, positive imaginary, and negative imaginary parts of complex modulation symbols like QAM symbols. The QCM scheme does not need Hermitian symmetry operation to generate LED compatible positive real transmit signals. Instead it exploits spatial indexing of LEDs to convey sign information. The proposed QCM module can serve as a basic building block to bring in the benefits of complex modulation to VLC. For example, QCM with phase rotation (QAM-PR) where the complex modulation symbols are rotated in phase before mapping the signals to the LEDs achieves improved bit error performance. We also find that the proposed QCM when used along with OFDM, termed as QCM-OFDM, achieves very good performance