2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2012
The development of novel treatments for many slowly progressing diseases, such as Alzheimer&a... more The development of novel treatments for many slowly progressing diseases, such as Alzheimer's disease (AD), is dependent on the ability to monitor and detect changes in disease progression. In some diseases the distinct clinical stages of the disease progress far too slowly to enable a quick evaluation of the efficacy of a given proposed treatment. To help improve the assessment of disease progression, we propose using Hidden Markov Models (HMM's) to model, in a more granular fashion, disease progression as compared to the clinical stages of the disease. Unlike many other applications of Hidden Markov Models, we train our HMM in an unsupervised way and then evaluate how effective the model is at uncovering underlying statistical patterns in disease progression by considering HMM states as disease stages. In this study, we focus on AD and show that our model, when evaluated on the cross validation data, can identify more granular disease stages than the three currently accepted clinical stages of "Normal", "MCI" (Mild Cognitive Impairment), and "AD".
Compulsive hoarding and saving symptoms, found in many patients with obsessive-compulsive disorde... more Compulsive hoarding and saving symptoms, found in many patients with obsessive-compulsive disorder (OCD), are part of a discrete clinical syndrome that includes indecisiveness, disorganization, perfectionism, procrastination, and avoidance and has been associated with poor response to medications and cognitive behavior therapy. The authors sought to identify cerebral metabolic patterns specifically associated with the compulsive hoarding syndrome using positron emission tomography (PET). [(18)F]Fluorodeoxyglucose PET scans were obtained for 45 adult subjects who met DSM-IV criteria for OCD (12 of whom had compulsive hoarding as their most prominent OCD symptom factor) and 17 normal comparison subjects. All subjects had been free of psychotropic medication for at least 4 weeks. Regional cerebral glucose metabolism was compared between the groups. In relation to the comparison subjects, the patients with compulsive hoarding syndrome had significantly lower glucose metabolism in the po...
While neurodegenerative diseases are characterized by steady degeneration over relatively long ti... more While neurodegenerative diseases are characterized by steady degeneration over relatively long timelines, it is widely believed that the early stages are the most promising for therapeutic intervention, before irreversible neuronal loss occurs. Developing a therapeutic response requires a precise measure of disease progression. However, since the early stages are for the most part asymptomatic, obtaining accurate measures of disease progression is difficult. Longitudinal databases of hundreds of subjects observed during several years with tens of validated biomarkers are becoming available, allowing the use of computational methods. We propose a widely applicable statistical methodology for creating a disease progression score (DPS), using multiple biomarkers, for subjects with a neurodegenerative disease. The proposed methodology was evaluated for Alzheimer's disease (AD) using the publicly available AD Neuroimaging Initiative (ADNI) database, yielding an Alzheimer's DPS or ADPS score for each subject and each time-point in the database. In addition, a common description of biomarker changes was produced allowing for an ordering of the biomarkers. The Rey Auditory Verbal Learning Test delayed recall was found to be the earliest biomarker to become abnormal. The group of biomarkers comprising the volume of the hippocampus and the protein concentration amyloid beta and Tau were next in the timeline, and these were followed by three cognitive biomarkers. The proposed methodology thus has potential to stage individuals according to their state of disease progression relative to a population and to deduce common behaviors of biomarkers in the disease itself.
Compulsive hoarding and saving symptoms, found in many patients with obsessive-compulsive disorde... more Compulsive hoarding and saving symptoms, found in many patients with obsessive-compulsive disorder (OCD), are part of a discrete clinical syndrome that includes indecisiveness, disorganization, perfectionism, procrastination, and avoidance and has been associated with poor response to medications and cognitive behavior therapy. The authors sought to identify cerebral metabolic patterns specifically associated with the compulsive hoarding syndrome using positron emission tomography (PET). [(18)F]Fluorodeoxyglucose PET scans were obtained for 45 adult subjects who met DSM-IV criteria for OCD (12 of whom had compulsive hoarding as their most prominent OCD symptom factor) and 17 normal comparison subjects. All subjects had been free of psychotropic medication for at least 4 weeks. Regional cerebral glucose metabolism was compared between the groups. In relation to the comparison subjects, the patients with compulsive hoarding syndrome had significantly lower glucose metabolism in the posterior cingulate gyrus and cuneus, whereas the nonhoarding OCD patients had significantly higher glucose metabolism in the bilateral thalamus and caudate. In relation to nonhoarding OCD patients, compulsive hoarders had significantly lower metabolism in the dorsal anterior cingulate gyrus. Across all OCD patients, hoarding severity was negatively correlated with glucose metabolism in the dorsal anterior cingulate gyrus. OCD patients with the compulsive hoarding syndrome had a different pattern of cerebral glucose metabolism than nonhoarding OCD patients and comparison subjects. Obsessive-compulsive hoarding may be a neurobiologically distinct subgroup or variant of OCD whose symptoms and poor response to anti-obsessional treatment are mediated by lower activity in the cingulate cortex.
2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2012
The development of novel treatments for many slowly progressing diseases, such as Alzheimer&a... more The development of novel treatments for many slowly progressing diseases, such as Alzheimer's disease (AD), is dependent on the ability to monitor and detect changes in disease progression. In some diseases the distinct clinical stages of the disease progress far too slowly to enable a quick evaluation of the efficacy of a given proposed treatment. To help improve the assessment of disease progression, we propose using Hidden Markov Models (HMM's) to model, in a more granular fashion, disease progression as compared to the clinical stages of the disease. Unlike many other applications of Hidden Markov Models, we train our HMM in an unsupervised way and then evaluate how effective the model is at uncovering underlying statistical patterns in disease progression by considering HMM states as disease stages. In this study, we focus on AD and show that our model, when evaluated on the cross validation data, can identify more granular disease stages than the three currently accepted clinical stages of "Normal", "MCI" (Mild Cognitive Impairment), and "AD".
Compulsive hoarding and saving symptoms, found in many patients with obsessive-compulsive disorde... more Compulsive hoarding and saving symptoms, found in many patients with obsessive-compulsive disorder (OCD), are part of a discrete clinical syndrome that includes indecisiveness, disorganization, perfectionism, procrastination, and avoidance and has been associated with poor response to medications and cognitive behavior therapy. The authors sought to identify cerebral metabolic patterns specifically associated with the compulsive hoarding syndrome using positron emission tomography (PET). [(18)F]Fluorodeoxyglucose PET scans were obtained for 45 adult subjects who met DSM-IV criteria for OCD (12 of whom had compulsive hoarding as their most prominent OCD symptom factor) and 17 normal comparison subjects. All subjects had been free of psychotropic medication for at least 4 weeks. Regional cerebral glucose metabolism was compared between the groups. In relation to the comparison subjects, the patients with compulsive hoarding syndrome had significantly lower glucose metabolism in the po...
While neurodegenerative diseases are characterized by steady degeneration over relatively long ti... more While neurodegenerative diseases are characterized by steady degeneration over relatively long timelines, it is widely believed that the early stages are the most promising for therapeutic intervention, before irreversible neuronal loss occurs. Developing a therapeutic response requires a precise measure of disease progression. However, since the early stages are for the most part asymptomatic, obtaining accurate measures of disease progression is difficult. Longitudinal databases of hundreds of subjects observed during several years with tens of validated biomarkers are becoming available, allowing the use of computational methods. We propose a widely applicable statistical methodology for creating a disease progression score (DPS), using multiple biomarkers, for subjects with a neurodegenerative disease. The proposed methodology was evaluated for Alzheimer's disease (AD) using the publicly available AD Neuroimaging Initiative (ADNI) database, yielding an Alzheimer's DPS or ADPS score for each subject and each time-point in the database. In addition, a common description of biomarker changes was produced allowing for an ordering of the biomarkers. The Rey Auditory Verbal Learning Test delayed recall was found to be the earliest biomarker to become abnormal. The group of biomarkers comprising the volume of the hippocampus and the protein concentration amyloid beta and Tau were next in the timeline, and these were followed by three cognitive biomarkers. The proposed methodology thus has potential to stage individuals according to their state of disease progression relative to a population and to deduce common behaviors of biomarkers in the disease itself.
Compulsive hoarding and saving symptoms, found in many patients with obsessive-compulsive disorde... more Compulsive hoarding and saving symptoms, found in many patients with obsessive-compulsive disorder (OCD), are part of a discrete clinical syndrome that includes indecisiveness, disorganization, perfectionism, procrastination, and avoidance and has been associated with poor response to medications and cognitive behavior therapy. The authors sought to identify cerebral metabolic patterns specifically associated with the compulsive hoarding syndrome using positron emission tomography (PET). [(18)F]Fluorodeoxyglucose PET scans were obtained for 45 adult subjects who met DSM-IV criteria for OCD (12 of whom had compulsive hoarding as their most prominent OCD symptom factor) and 17 normal comparison subjects. All subjects had been free of psychotropic medication for at least 4 weeks. Regional cerebral glucose metabolism was compared between the groups. In relation to the comparison subjects, the patients with compulsive hoarding syndrome had significantly lower glucose metabolism in the posterior cingulate gyrus and cuneus, whereas the nonhoarding OCD patients had significantly higher glucose metabolism in the bilateral thalamus and caudate. In relation to nonhoarding OCD patients, compulsive hoarders had significantly lower metabolism in the dorsal anterior cingulate gyrus. Across all OCD patients, hoarding severity was negatively correlated with glucose metabolism in the dorsal anterior cingulate gyrus. OCD patients with the compulsive hoarding syndrome had a different pattern of cerebral glucose metabolism than nonhoarding OCD patients and comparison subjects. Obsessive-compulsive hoarding may be a neurobiologically distinct subgroup or variant of OCD whose symptoms and poor response to anti-obsessional treatment are mediated by lower activity in the cingulate cortex.
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