@proceedings {989, title = {Impact of free-water correction on white matter changes measured by diffusion tensor imaging in migraine}, volume = {4601}, year = {2023}, month = {2023}, abstract = {
Menstrual migraine affects about 25\% of female migraine patients. However, the diagnosis of migraine is particularly difficult because the brain changes associated with migraine are challenging to detect with imaging techniques. Diffusion-weighted MRI (dMRI) permits the detection of alterations in the microenvironment of the brain tissues. We investigate whether removing the contribution of the free water component from the diffusion-signal can provide increased sensitivity to identify white matter changes in migraine using diffusion tensor metrics.
}, author = {Guadilla, Irene and Fouto, Ana and {\'A}lvaro Planchuelo-G{\'o}mez and Trist{\'a}n-Vega, Antonio and Ruiz-Tagle, Amparo and Esteves, In{\^e}s and Caetano, Gina and Silva, Nuno and Vilela, Pedro and Gil-Gouveia, Raquel and Aja-Fern{\'a}ndez, Santiago and Figueiredo, Patr{\'\i}cia and Nunes, Rita} } @article {994, title = {Increased MRI-based Brain Age in chronic migraine patients}, journal = {The Journal of Headache and Pain}, volume = {24}, year = {2023}, pages = {133}, abstract = {Neuroimaging has revealed that migraine is linked to alterations in both the structure and function of the brain. However, the relationship of these changes with aging has not been studied in detail. Here we employ the Brain Age framework to analyze migraine, by building a machine-learning model that predicts age from neuroimaging data. We hypothesize that migraine patients will exhibit an increased Brain Age Gap (the difference between the predicted age and the chronological age) compared to healthy participants.
}, keywords = {Biomarkers, Brain age, machine learning, migraine disorders, neuroimaging}, issn = {1129-2377}, doi = {10.1186/s10194-023-01670-6}, url = {https://doi.org/10.1186/s10194-023-01670-6}, author = {Navarro-Gonz{\'a}lez, Rafael and Garc{\'\i}a-Azor{\'\i}n, David and Guerrero-Peral, {\'A}ngel L. and {\'A}lvaro Planchuelo-G{\'o}mez and Aja-Fern{\'a}ndez, Santiago and de Luis-Garc{\'\i}a, Rodrigo} } @proceedings {986, title = {Increased T1w MRI-based brain age in chronic migraine patients}, volume = {5327}, year = {2023}, month = {2023}, abstract = {Brain-age is an emerging neuroimaging biomarker that represents the aging status of the brain using machine learning techniques from MRI data. It has been successfully applied to the study of different neurological and psychiatric conditions. We hypothesize that patients with migraine may show an increased brain age gap (difference between the age estimated from the MRI data and the chronological age). After building a brain age model from 2,781 healthy subjects, we tested this hypothesis on a dataset with 210 healthy controls and migraine patients. Results showed an increased brain age in chronic migraine patients with respect to healthy controls.
}, author = {Navarro-Gonz{\'a}lez, Rafael and Garc{\'\i}a-Azor{\'\i}n, David and Guerrero, {\'A}ngel L and {\'A}lvaro Planchuelo-G{\'o}mez and Aja-Fern{\'a}ndez, Santiago and de Luis-Garc{\'\i}a, Rodrigo} } @conference {975, title = {Comparing signal models for correcting diffusion-weighted MR images for free water partial volume effects}, booktitle = {ISMRM Workshop on Diffusion MRI: From Research to Clinic}, year = {2022}, address = {Amsterdam, The Netherlands}, author = {Guadilla, Irene and Fouto, Ana R. and {\'A}lvaro Planchuelo-G{\'o}mez and Trist{\'a}n-Vega, Antonio and Ruiz-Tagle, Amparo and Esteves, In{\^e}s and Caetano, Gina and Aja-Fern{\'a}ndez, Santiago and Figueiredo, Patr{\'\i}cia and Nunes, Rita G.} } @article {963, title = {Synthetic MRI improves radiomics-based glioblastoma survival prediction}, journal = {NMR in Biomedicine}, year = {2022}, chapter = {e4754}, doi = {10.1002/nbm.4754}, author = {Elisa Moya-S{\'a}ez and Rafael Navarro-Gonz{\'a}lez and Santiago Cepeda and {\'A}ngel P{\'e}rez-N{\'u}{\~n}ez and Rodrigo de Luis-Garcia and Santiago Aja-Fernández and Carlos Alberola-L{\'o}pez} } @article {952, title = {Effects of the onabotulinumtoxinA follow-up delay in migraine course during the COVID-19 lockdown}, journal = {Neurological Sciences}, volume = {42}, year = {2021}, pages = {5087-5092}, issn = {1590-3478}, doi = {10.1007/s10072-021-05180-8}, url = {https://doi.org/10.1007/s10072-021-05180-8}, author = {Gonzalez-Martinez, Alicia and {\'A}lvaro Planchuelo-G{\'o}mez and {\'A}ngel L. Guerrero and Garc{\'\i}a-Azor{\'\i}n, David and Santos-Lasaosa, Sonia and Navarro-P{\'e}rez, Mar{\'\i}a Pilar and Odriozola-Gonz{\'a}lez, Paula and Irurtia, Mar{\'\i}a Jes{\'u}s and Quintas, Sonia and de Luis-Garc{\'\i}a, Rodrigo and Ana B Gago-Veiga} } @article {944, title = {Evaluation of the Impact of the COVID-19 Lockdown in the Clinical Course of Migraine}, journal = {Pain Medicine}, volume = {22}, year = {2021}, month = {2021}, pages = {2079-2091}, abstract = {Objective: Previous studies have demonstrated that emotional stress, changes in lifestyle habits and infections can worsen the clinical course of migraine. We hypothesize that changes in habits and medical care during coronavirus disease 2019 (COVID-19) lockdown might have worsened the clinical course of migraine.
Design: Retrospective survey study collecting online responses from migraine patients followed-up by neurologists at three tertiary hospitals between June and July 2020.
Methods: We used a web-based survey that included demographic data, clinical variables related with any headache (frequency) and migraine (subjective worsening, frequency, and intensity), lockdown, and symptoms of post-traumatic stress.
Results: The response rate of the survey was 239/324 (73.8\%). The final analysis included 222 subjects. Among them, 201/222 (90.5\%) were women, aged 42.5 +- 12.0 (mean+-SD). Subjective improvement of migraine during lockdown was reported in 31/222 participants (14.0\%), while worsening in 105/222 (47.3\%) and was associated with changes in migraine triggers such as stress related to going outdoors and intake of specific foods or drinks. Intensity of attacks increased in 67/222 patients (30.2\%), and it was associated with the subjective worsening, female sex, recent insomnia, and use of acute medication during a headache. An increase in monthly days with any headache was observed in 105/222 patients (47.3\%) and was related to symptoms of post-traumatic stress, older age and living with five or more people.
Conclusions: Approximately half the migraine patients reported worsening of their usual pain during the lockdown. Worse clinical course in migraine patients was related to changes in triggers and the emotional impact of the lockdown.
}, keywords = {COVID-19, Headache, Lockdown, Migraine, SARS-CoV-2}, issn = {1526-4637}, doi = {10.1093/pm/pnaa449}, url = {https://doi.org/10.1093/pm/pnaa449}, author = {Gonzalez-Martinez, Alicia and {\'A}lvaro Planchuelo-G{\'o}mez and {\'A}ngel L. Guerrero and Garc{\'\i}a-Azor{\'\i}n, David and Santos-Lasaosa, Sonia and Navarro-P{\'e}rez, Mar{\'\i}a Pilar and Odriozola-Gonz{\'a}lez, Paula and Irurtia, Mar{\'\i}a Jes{\'u}s and Quintas, Sonia and Rodrigo de Luis-Garc{\'\i}a and Ana B Gago-Veiga} } @conference {940, title = {Evaluation of the burden of migraine on the partners lifestyle: a multicenter study}, booktitle = {International Headache Congress 2021}, year = {2021}, month = {2021}, publisher = {International Headache Society \& European Headache Federation}, organization = {International Headache Society \& European Headache Federation}, address = {Virtual Congress}, abstract = {Objective: Migraine is a highly disabling disease that affects the patient{\textquoteright}s life, but its consequences on the patient{\textquoteright}s partner have been barely studied. The objective was to analyze these effects on romantic relationship, relationship with their children, friendship and work; as well as to evaluate caregiver burden and the presence of anxiety and/or depression.
Methods: Cross-sectional observational study. An online survey was filled by partners of migraine patients from five Spanish Headache Units. Questions about the four assessed areas and two scales to evaluate anxiety, depression and caregiver burden (Hospital Anxiety and Depression Scale and Zarit scale) were included. The presence of anxiety and depression was compared to the Spanish prevalence (6.7\% in both cases).
Results: Out of 176 registered responses, 155 were accepted. The sample included 86.5\% of women, with mean age 44.2 +- 10.4 years. Effects on partners were found on love relationship and items concerning children and friendships, with a minor impact at work. Partners showed a significant moderate burden according to the Zarit scale (p = 12/155 = 0.077 [0.041-0.131]; p \< 0.001) and a higher anxiety rate than the 6.7\% national prevalence (p = 23/155 = 0.148 [0.096-0.214]; p \< 0.001), but similar depression rate.
Conclusion: We found an impact on the patient{\textquoteright}s partners on the studied areas. Migraine is a disease that implies caregiver burden in the patient{\textquoteright}s environment with possible effect on anxiety levels.
Objective: During the COVID-19 pandemic face-to-face procedures have been postponed. We aim to evaluate the impact of onabotulinumtoxinA follow-up delay in migraine during COVID-19 pandemic.
Methods: Subjective worsening, intensity of migraine attacks and frequency of headache and migraine were retrospectively compared between patients with unmodified and interrupted onabotulinumtoxinA follow-up in Headache Units.
Results: We included 67 patients with chronic migraine or high-frequency episodic migraine under onabotulinumtoxinA treatment, 65 (97.0\%) female,
44.5 +- 12.1 years old. Treatment administration was voluntarily delayed in 14 (20.9\%) patients and nine (13.4\%) were unable to continue follow-up. Patients with uninterrupted follow-up during lockdown presented 8.4 and 8.1 less monthly days with headache (adjusted p = 0.011) and migraine attacks (adjusted p = 0.009) compared to patients whose follow-up was interrupted, respectively.
Conclusion: Involuntary delay of onabotulinumtoxinA follow-up in patients with migraine due to COVID-19 pandemic was associated with a higher frequency of headache and migraine attacks. Safe administration of onabotulinumtoxinA during lockdown should be promoted.
Schizophrenia and bipolar disorder include patients with different characteristics, which may hamper the definition of biomarkers. One of the dimensions with greater heterogeneity among these patients is cognition. Recent studies support the identification of different patients{\textquoteright} subgroups along the cognitive domain using cluster analysis. Our aim was to validate clusters defined on the basis of patients{\textquoteright} cognitive status and to assess its relation with demographic, clinical and biological measurements. We hypothesized that subgroups characterized by different cognitive profiles would show differences in an array of biological data. Cognitive data from 198 patients (127 with chronic schizophrenia, 42 first episodes of schizophrenia and 29 bipolar patients) were analyzed by a K-means cluster approach and were compared on several clinical and biological variables. We also included 155 healthy controls for further comparisons. A two-cluster solution was selected, including a severely impaired group and a moderately impaired group. The severely impaired group was associated with higher illness duration and symptoms scores, lower thalamus and hippocampus volume, lower frontal connectivity and basal hypersynchrony in comparison to controls and the moderately impaired group. Moreover, both patients{\textquoteright} groups showed lower cortical thickness and smaller functional connectivity modulation than healthy controls. This study supports the existence of different cognitive subgroups within the psychoses with different neurobiological underpinnings.
}, keywords = {Cognition, Connectivity, Modulation, Volume, bipolar disorder, schizophrenia}, issn = {0920-9964}, doi = {https://doi.org/10.1016/j.schres.2020.11.013}, url = {https://www.sciencedirect.com/science/article/pii/S0920996420305521}, author = {Fern{\'a}ndez-Linsenbarth, In{\'e}s and {\'A}lvaro Planchuelo-G{\'o}mez and D{\'\i}ez, {\'A}lvaro and Arjona-Valladares, Antonio and Rodrigo de Luis-Garc{\'\i}a and Mart{\'\i}n-Santiago, {\'O}scar and Benito-S{\'a}nchez, Jos{\'e} Antonio and P{\'e}rez-Laureano, {\'A}ngela and Gonz{\'a}lez-Parra, David and Montes-Gonzalo, Carmen and Melero-Lerma, Raquel and Fern{\'a}ndez Morante, Sonia and Sanz-Fuentenebro, Javier and G{\'o}mez-Pilar, Javier and N{\'u}{\~n}ez-Novo, Pablo and Molina, Vicente} } @article {953, title = {Search for schizophrenia and bipolar biotypes using functional network properties}, journal = {Brain and Behavior}, volume = {11}, year = {2021}, pages = {e2415}, abstract = {Introduction: Recent studies support the identification of valid subtypes within schizophrenia and bipolar disorder using cluster analysis. Our aim was to identify meaningful biotypes of psychosis based on network properties of the electroencephalogram. We hypothesized that these parameters would be more altered in a subgroup of patients also characterized by more severe deficits in other clinical, cognitive, and biological measurements.
Methods: A clustering analysis was performed using the electroencephalogram-based network parameters derived from graph-theory obtained during a P300 task of 137 schizophrenia (of them, 35 first episodes) and 46 bipolar patients. Both prestimulus and modulation of the electroencephalogram were included in the analysis. Demographic, clinical, cognitive, structural cerebral data, and the modulation of the spectral entropy of the electroencephalogram were compared between clusters. Data from 158 healthy controls were included for further comparisons.
Results: We identified two clusters of patients. One cluster presented higher prestimulus connectivity strength, clustering coefficient, path-length, and lower small-world index compared to controls. The modulation of clustering coefficient and path-length parameters was smaller in the former cluster, which also showed an altered structural connectivity network and a widespread cortical thinning. The other cluster of patients did not show significant differences with controls in the functional network properties. No significant differences were found between patients{\textasciiacute} clusters in first episodes and bipolar proportions, symptoms scores, cognitive performance, or spectral entropy modulation.
Conclusion: These data support the existence of a subgroup within psychosis with altered global properties of functional and structural connectivity.
}, keywords = {Biotypes, bipolar disorder, diffusion, electroencephalogram, network, schizophrenia}, doi = {https://doi.org/10.1002/brb3.2415}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/brb3.2415}, author = {Fern{\'a}ndez-Linsenbarth, In{\'e}s and {\'A}lvaro Planchuelo-G{\'o}mez and Be{\~n}o-Ruiz-de-la-Sierra, Rosa M. and D{\'\i}ez, Alvaro and Arjona, Antonio and P{\'e}rez, Adela and Rodr{\'\i}guez-Lorenzana, Alberto and del Valle, Pilar and de Luis-Garc{\'\i}a, Rodrigo and Mascialino, Guido and Holgado-Madera, Pedro and Segarra-Echevarr{\'\i}a, Rafael and Gomez-Pilar, Javier and N{\'u}{\~n}ez, Pablo and Bote-Boneaechea, Berta and Zambrana-G{\'o}mez, Antonio and Roig-Herrero, Alejandro and Molina, Vicente} } @article {912, title = {On the generalizability of diffusion MRI signal representations across acquisition parameters, sequences and tissue types: chronicles of the MEMENTO challenge}, journal = {bioRxiv}, year = {2021}, month = {2021}, doi = {10.1101/2021.03.02.433228}, url = {https://www.biorxiv.org/content/early/2021/03/02/2021.03.02.433228}, author = {De Luca, Alberto and Ianus, Andrada and Leemans, Alexander and Palombo, Marco and Shemesh, Noam and Zhang, Hui and Alexander, Daniel C and Nilsson, Markus and Froeling, Martijn and Biessels, Geert-Jan and Zucchelli, Mauro and Frigo, Matteo and Albay, Enes and Sedlar, Sara and Alimi, Abib and Deslauriers-Gauthier, Samuel and Deriche, Rachid and Fick, Rutger and Maryam Afzali and Tomasz Pieciak and Bogusz, Fabian and Santiago Aja-Fern{\'a}ndez and Ozarslan, Evren and Derek K. Jones and Chen, Haoze and Jin, Mingwu and Zhang, Zhijie and Wang, Fengxiang and Nath, Vishwesh and Parvathaneni, Prasanna and Morez, Jan and Sijbers, Jan and Jeurissen, Ben and Fadnavis, Shreyas and Endres, Stefan and Rokem, Ariel and Garyfallidis, Eleftherios and Sanchez, Irina and Prchkovska, Vesna and Rodrigues, Paulo and Landman, Bennet A and Schilling, Kurt G} } @article {933, title = {On the generalizability of diffusion MRI signal representations across acquisition parameters, sequences and tissue types: chronicles of the MEMENTO challenge}, journal = {NeuroImage}, year = {2021}, month = {2021}, pages = {118367}, issn = {1053-8119}, doi = {https://doi.org/10.1016/j.neuroimage.2021.118367}, url = {https://www.sciencedirect.com/science/article/pii/S1053811921006431}, author = {Alberto De Luca and Andrada Ianus and Alexander Leemans and Marco Palombo and Noam Shemesh and Hui Zhang and Daniel C. Alexander and Markus Nilsson and Martijn Froeling and Geert-Jan Biessels and Mauro Zucchelli and Matteo Frigo and Enes Albay and Sara Sedlar and Abib Alimi and Samuel Deslauriers-Gauthier and Rachid Deriche and Rutger Fick and Maryam Afzali and Tomasz Pieciak and Fabian Bogusz and Santiago Aja-Fern{\'a}ndez and Evren {\"O}zarslan and Derek K. Jones and Haoze Chen and Mingwu Jin and Zhijie Zhang and Fengxiang Wang and Vishwesh Nath and Prasanna Parvathaneni and Jan Morez and Jan Sijbers and Ben Jeurissen and Shreyas Fadnavis and Stefan Endres and Ariel Rokem and Eleftherios Garyfallidis and Irina Sanchez and Vesna Prchkovska and Paulo Rodrigues and Bennet A. Landman and Kurt G. Schilling} } @article {843, title = {Identificacion of MRI-based psychosis subtypes: Replication and refinement}, journal = {Progress in Neuro-Psychopharmacology and Biological Psychiatry}, volume = {100}, year = {2020}, pages = {109907}, abstract = {The identification of the cerebral substrates of psychoses such as schizophrenia and bipolar disorder is likely hampered by its biological heterogeneity, which may contribute to the low replication of results in the field. In this study we aimed to replicate in a completely new sample and supplement the results of a previous study with additional data on this topic. In the aforementioned study we identified a schizophrenia cluster characterized by high mean cortical curvature and low cortical thickness, subcortical hypometabolism and progressive negative symptoms. Here, we have used magnetic resonance images from 61 schizophrenia and 28 bipolar patients, as well as 51 healthy controls and a cluster analysis to search for possible subgroups primarily characterized by cerebral structural data. Diffusion tensor imaging (fractional anisotropy, FA), cognition, clinical data and electroencephalographic (EEG) modulation during a P300 task were used to validate the possible clusters. Two clusters of patients were identified. The first cluster (29 schizophrenia and 18 bipolar patients) showed decreased cortical thickness and area values, as well as lower subcortical volumes and higher cortical curvature in some regions, as compared to the second cluster. This first cluster also showed decreased FA in frontal lobe connections and worse cognitive performance. Although this cluster also showed longer illness duration, there were first episode patients in both clusters and treatment doses and types were not different between clusters. Both clusters of patients showed decreased EEG task-related modulation. In conclusion, our data give additional support to a distinct biologically based cluster encompassing schizophrenia and bipolar disorder patients with cortical and subcortical alterations, hampered cortical connectivity and lower cognitive performance.
}, keywords = {Biotypes, Cortical thickness, Curvature, Subtypes, bipolar disorder, schizophrenia}, issn = {0278-5846}, doi = {https://doi.org/10.1016/j.pnpbp.2020.109907}, url = {http://www.sciencedirect.com/science/article/pii/S0278584619309595}, author = {{\'A}lvaro Planchuelo-G{\'o}mez and Lubeiro, Alba and N{\'u}{\~n}ez-Novo, Pablo and Gomez-Pilar, Javier and Rodrigo de Luis-Garc{\'\i}a and del Valle, Pilar and Mart{\'\i}n-Santiago, {\'O}scar and P{\'e}rez-Escudero, Adela and Vicente Molina} } @article {476, title = {Localized abnormalities in the cingulum bundle in patients with schizophrenia: A Diffusion Tensor tractography study}, journal = {NeuroImage: Clinical}, volume = {5}, year = {2014}, pages = {93{\textendash}99}, abstract = {The cingulum bundle (CB) connects gray matter structures of the limbic system and as such has been implicated in the etiology of schizophrenia. There is growing evidence to suggest that the CB is actually comprised of a conglomeration of discrete sub-connections. The present study aimed to use Diffusion Tensor tractography to subdivide the CB into its constituent sub-connections, and to investigate the structural integrity of these sub-connections in patients with schizophrenia and matched healthy controls. Diffusion Tensor Imaging scans were acquired from 24 patients diagnosed with chronic schizophrenia and 26 matched healthy controls. Deterministic tractography was used in conjunction with FreeSurfer-based regions-of-interest to subdivide the CB into 5 sub-connections (I1 to I5). The patients with schizophrenia exhibited subnormal levels of FA in two cingulum sub-connections, specifically the fibers connecting the rostral and caudal anterior cingulate gyrus (I1) and the fibers connecting the isthmus of the cingulate with the parahippocampal cortex (I4). Furthermore, while FA in the I1 sub-connection was correlated with the severity of patients{\textquoteright} positive symptoms (specifically hallucinations and delusions), FA in the I4 sub-connection was correlated with the severity of patients{\textquoteright} negative symptoms (specifically affective flattening and anhedonia/asociality). These results support the notion that the CB is a conglomeration of structurally interconnected yet functionally distinct sub-connections, of which only a subset are abnormal in patients with schizophrenia. Furthermore, while acknowledging the fact that the present study only investigated the CB, these results suggest that the positive and negative symptoms of schizophrenia may have distinct neurobiological underpinnings.
}, author = {Whitford, Thomas J and Lee, Sun Woo and Oh, Jungsu S and Rodrigo de Luis-Garc{\'\i}a and Savadjiev, Peter and Alvarado, Jorge L and Carl-Fredik Westin and Niznikiewicz, Margaret and Nestor, Paul G and McCarley, Robert W} } @conference {gonzalez2013applying, title = {Applying a parametric approach for the task of nonstationary noise removal with missing information}, booktitle = {Computational Cybernetics (ICCC), 2013 IEEE 9th International Conference on}, year = {2013}, pages = {23{\textendash}28}, publisher = {IEEE}, organization = {IEEE}, author = {Luis Gonz{\'a}lez-Jaime and Nachtegeal, Mike and Kerre, Etienne and Gonzalo Vegas-S{\'a}nchez-Ferrero and Santiago Aja-Fern{\'a}ndez} } @inbook {gonzalez2013parametric, title = {Parametric Image Restoration Using Consensus: An Application to Nonstationary Noise Filtering}, booktitle = {Pattern Recognition and Image Analysis}, year = {2013}, pages = {358{\textendash}365}, publisher = {Springer Berlin Heidelberg}, organization = {Springer Berlin Heidelberg}, author = {Luis Gonz{\'a}lez-Jaime and Nachtegeal, Mike and Kerre, Etienne and Gonzalo Vegas-S{\'a}nchez-Ferrero and Santiago Aja-Fern{\'a}ndez} } @article {aja2008restoration, title = {Restoration of DWI data using a Rician LMMSE estimator}, journal = {Medical Imaging, IEEE Transactions on}, volume = {27}, number = {10}, year = {2008}, pages = {1389{\textendash}1403}, publisher = {IEEE}, author = {Santiago Aja-Fern{\'a}ndez and Niethammer, Marc and Kubicki, Marek and Martha E Shenton and Carl-Fredik Westin} } @inbook {niethammer2007outlier, title = {Outlier rejection for diffusion weighted imaging}, booktitle = {Medical Image Computing and Computer-Assisted Intervention{\textendash}MICCAI 2007}, year = {2007}, pages = {161{\textendash}168}, publisher = {Springer Berlin Heidelberg}, organization = {Springer Berlin Heidelberg}, author = {Niethammer, Marc and Bouix, Sylvain and Santiago Aja-Fern{\'a}ndez and Carl-Fredik Westin and Martha E Shenton} } @article {bouix2007evaluating, title = {On evaluating brain tissue classifiers without a ground truth}, journal = {Neuroimage}, volume = {36}, number = {4}, year = {2007}, pages = {1207{\textendash}1224}, publisher = {Academic Press}, author = {Bouix, Sylvain and Marcos Martin-Fernandez and Ungar, Lida and Nakamura, Motoaki and Koo, Min-Seong and McCarley, Robert W and Martha E Shenton} } @conference {412, title = {Estimates of constrained multi-class a posteriori probabilities in time series problems with neural networks}, booktitle = {Proceedings of the International Joint Conference on Neural Networks}, year = {1999}, publisher = {IEEE, United States}, organization = {IEEE, United States}, address = {Washington, DC, USA}, abstract = {In time series problems, where time ordering is a crucial issue, the use of Partial Likelihood Estimation (PLE) represents a specially suitable method for the estimation of parameters in the model. We propose a new general supervised neural network algorithm, Joint Network and Data Density Estimation (JNDDE), that employs PLE to approximate conditional probability density functions for multi-class classification problems. The logistic regression analysis is generalized to multiple class problems with softmax regression neural network used to model the a-posteriori probabilities such that they are approximated by the network outputs. Constraints to the network architecture, as well as to the model of data, are imposed, resulting in both a flexible network architecture and distribution modeling. We consider application of JNDDE to channel equalization and present simulation results.
}, keywords = {Approximation theory, Computer simulation, Constraint theory, Data structures, Joint network-data density estimation (JNDDE), Mathematical models, Multi-class a posteriori probabilities, Neural networks, Partial likelihood estimation (PLE), Probability density function, Regression analysis}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-0033325263\&partnerID=40\&md5=8c6134020b0b2a9c5ab05b131c070b88}, author = {J I Arribas and Jes{\'u}s Cid-Sueiro and T Adali and H Ni and B Wang and A R Figueiras-Vidal} }