Mohsin Raza

IMPEDIMENTS TO IMPLEMENTING EVIDENCE-BASED MENTAL HEALTH IN DEVELOPING COUNTRIES

Mental and behavioural disorders are among the most important causes of morbidity and disability in both the developed and the developing world.1 As a proportion of total morbidity and disability, these problems are comparatively less significant in developing countries, mainly because of the large burden of communicable, maternal, perinatal, and nutritional conditions in these regions. However, mental disorders result in major deprivations such as lower levels of educational attainment, unemployment and, in extreme cases, homelessness of patients.1 The delivery of healthcare services including mental health in low and middle income countries presents a number of difficult challenges such as population explosion, unplanned urbanisation, scarcity of human resources, lack of reliable data, and lack of a systematic approach to healthcare distribution and referral systems.2 Clinicians attempting to practice evidence-based mental health face additional challenges. In the model proposed for evidence-based decision making,3 consideration of the clinical and physical circumstances are synthesised with research evidence and patients’ preferences, while clinical expertise is required to assemble these additional elements to provide optimal treatment. Given the different components of this model, we believe that existing differences could hinder application of evidence based practice in the developing world. In this report, we discuss some of these factors, emphasising those that can be changed. Prevention in mental health care is intimately linked with overall human and community development. The low priority and the limited resources for provision of mental health care raise two noticeable problems in developing countries.4 Policy makers generally place more emphasis on mortality oriented statistics, which are rather low for mental disorders. Recent studies, however, have tried to change this attitude with warnings that mental illnesses constitute up to 12% of the global burden of disease5 and that there are consistent relations between these disorders and widely …

Does drill-induced noise have an impact on sensorineural hearing during craniotomy procedure?

Objective. It is well known that exposure to noise can lead to hearing loss. Craniotomy drills have significant noise and vibration. Since a noise induced by the drill during craniotomy is thought to be one of the causes, we examined its effect on the sensorineural hearing in this study. Methods. Thirty-nine patients who had undergone craniotomy operations served as the basis for this study between Jul. 2007 and Dec. 2008. Standard pure-tone audiometry (PTA) and speech recognition thresholds (SRT) were calculated for all subjects before, one week and 1 year after craniotomy. Results. Statistically significant differences were not observed at the lower and middle frequencies (0.25–2 kHz), however, differences in the hearing thresholds at higher frequencies (4–6 kHz) were statistically significant before and after craniotomy. Mean pure-tone thresholds obtained was significantly more in older subjects when compared to young patients. Moreover, the correlation between increased number of burr holes and sensorineural hearing loss (SNHL) was statistically significant. Conclusions. We conclude that drill-generated noise during craniotomy has been incriminated as a cause of SNHL. Possible noise disturbance to the inner ear can only be avoided by minimizing the number of burr holes and the duration of harmful noise exposure to the cochlear structures.

Original article: Bifurcation analysis of the Poincaré map function of intracranial EEG signals in temporal lobe epilepsy patients

In this paper, the Poincare map function as a one-dimensional first-return map is obtained by approximating the scatter plots of inter-peak interval (IPI) during preictal and postictal periods from invasive EEG recordings of nine patients suffering from medically intractable focal epilepsy. Evolutionary Algorithm (EA) is utilized for parameter estimation of the Poincare map. Bifurcation analyses of the iterated map reveal that as the neuronal activity progresses from preictal state toward the ictal event, the parameter values of the Poincare map move toward the bifurcation points. However, following the seizure occurrence and in the postictal period, these parameter values move away from the bifurcation points. Both flip and fold bifurcations are analyzed and it is demonstrated that in some cases the flip bifurcation and in other cases the fold bifurcation are the dynamical regime underlying epileptiform events. This information can offer insights into the dynamical nature and variability of the brain signals and consequently could help to predict and control seizure events.

New role for astroglia in learning: Formation of muscle memory

Muscle memory can be described as gradual adaptation of muscles over a period of time to perform a new movement or action. Its precise mechanism is unknown; however, it is now known that when a motor skill is learned it leads to significant brain activity. Astrocytes are the most abundant glial cell types in the CNS that play an associative active role with neurons in learning and memory. They are interconnected to neurons via gap junctions forming astroglial network for fast communication and synchronization. We hypothesize that astroglial cells play main role in the formation of muscle memory and evaluate it by the experimental evidence published so far that indicates role of astroglia on various cellular and molecular aspects of muscle memory. The basis of our hypothesis is the fact that during training or motor learning period, neuronal output data related to learning lead to certain specific pattern for stimulating target muscles over a period of time and partly these data are stored in astroglial network. This stored data fine tune glial parameters that affect synaptic space and neuronal output used to perform rapid motor actions. For the validation of our hypothesis, we have generated a computational model for a section of neural pathway with astroglial network and have shown that the astroglial network by using inhibitory and stimulatory neurotransmitters can generate certain patterns, modulate and balance synaptic space across the neural pathway during acquisition of muscle memory.

Mechanisms of hippocampal astrocytes mediation of spatial memory and theta rhythm by gliotransmitters and growth factors

Our knowledge about encoding and maintenance of spatial memory emphasizes the integrated functional role of the grid cells and the place cells of the hippocampus in the generation of theta rhythm in spatial memory formation. However, the role of astrocytes in these processes is often underestimated in their contribution to the required structural and functional characteristics of hippocampal neural network operative in spatial memory. We show that hippocampal astrocytes, by the secretion of gliotransmitters, such as glutamate, d‐serine, and ATP and growth factors such as BDNF and by the expression of receptors and channels such as those of TNFα and aquaporin, have several diverse fuctions in spatial memory. We specifically focus on the role of astrocytes on five phases of spatial memory: (1) theta rhythm generation, (2) theta phase precession, (3) formation of spatial memory by mapping data of entorhinal grid cells into the place cells, (4) storage of spatial information, and (5) maintenance of spatial memory. Finally, by reviewing the literature, we propose specific mechanisms mentioned in the form of a hypothesis suggesting that astrocytes are important in spatial memory formation.

Conceptualization of category-oriented likelihood ratio: a useful tool for clinical diagnostic reasoning

BackgroundIn the diagnostic reasoning process medical students and novice physicians need to be made aware of the diagnostic values of the clinical findings (including history, signs, and symptoms) to make an appropriate diagnostic decision. Diagnostic reasoning has been understood in light of two paradigms on clinical reasoning: problem solving and decision making. They advocate the reasoning strategies used by expert physicians and the statistical models of reasoning, respectively. Evidence-based medicine (EBM) applies decision theory to the clinical diagnosis, which can be a challenging topic in medical education.This theoretical article tries to compare evidence-based diagnosis with expert-based strategies in clinical diagnosis and also defines a novel concept of category-oriented likelihood ratio (LR) to propose a new model combining both aforementioned methods.DiscussionEvidence-based medicine advocates the use of quantitative evidence to estimate the probability of diseases more accurately and objectively; however, the published evidence for a given diagnosis cannot practically be utilized in primary care, especially if the patient is complaining of a nonspecific problem such as abdominal pain that could have a long list of differential diagnoses. In this case, expert physicians examine the key clinical findings that could differentiate between broader categories of diseases such as organic and non-organic disease categories to shorten the list of differential diagnoses. To approach nonspecific problems, not only do the experts revise the probability estimate of specific diseases, but also they revise the probability estimate of the categories of diseases by using the available clinical findings.SummaryTo make this approach analytical and objective, we need to know how much more likely it is for a key clinical finding to be present in patients with one of the diseases of a specific category versus those with a disease not included in that category. In this paper, we call this value category-oriented LR.

Effect of BDNF secretion by astrocyte on learning and memory: A modeling approach

Astrocytes have been recently implicated in modulation of neuronal synapses leading to Long Term Potentiation, the cellular basis of learning. Astrocytes also secrete neurotrophins such as BDNF, which regulate synaptogenesis, lead to the formation of new network connections between neurons and alter synaptic plasticity underlying learning and memory. In this study, we modeled effects of BDNF secretion on the formation of new connections in hippocampus neural network. A biophysical neural network model consisting of two pyramidal neurons, two interneurons, and the astrocytes were studied. The corresponding dynamical properties were investigated by using numerical simulations. The proposed model was capable to show the function of secretion BDNF by astrocyte. Finally we showed that astrocytes by changing the structure of neural network through BDNF secretion via creation of new connections and increasing synaptic junctions elicited generation of different patterns in the output of neural network. These new output patterns were considered as results of effect of astrocyte on learning caused by BDNF secretion.

Response of the Pre-oriented Goal-directed Attention to Usual and Unusual Distractors: A Preliminary Study

Introduction: In this study, we investigated the distraction power of the unusual and usual images on the attention of 20 healthy primary school children. Methods: Our study was different from previous ones in that the participants were asked to fix the initial position of their attention on a predefined location after being presented with unusual images as distractors. The goals were presented in locations, which were far from the attraction basin of distractors. We expected that the pre-orienting of the attention to the position of targets would reduce the attractive effect of unusual images compared to the usual ones. The percentage of correct responses and the reaction time were measured as behavioral indicators of attention performance. Results: Results showed that using the goal-directed attention, subjects ignored both kinds of distractors nearly the same way. Conclusion: With regard to previous reports about more attraction towards the unusual images, it is suggested that the dynamics of the visual attention system be sensitive to the initial condition. That is, changing the initial position of the attention can lead to the decrement of the unusual images effects. However, several other possibilities such as a probable delay in processing unusual features could explain this observation, too.