Expertise

Functional Neuroimaging

"Understanding the human brain is one of the greatest challenges facing 21st century science"

Functional neuroimaging and the associated computing technologies play a principal role in this and other efforts of this kind, with functional magnetic resonance imaging (fMRI) and electro-encephalography (EEG) being the most widely used and thoroughly studied modalities for brain mapping.

Their objectives include analysis of the activity and functional connectivity of the brain, and their popularity arises from their non-invasive nature and their ability to provide maps of high spatial (fMRI) or temporal (EEG) resolution.

Each of these modalities exhibits its own advantages and disadvantages and provides an alternative view of the brain function. fMRI has been used to answer research questions in a wide range of disciplines, such as cognitive neuroscience and experimental psychology.

There are various objectives in the analysis of fMRI data, the most common of which being the localization of brain regions activated by a certain task, the determination of distributed functional brain networks (FBNS) that correspond to certain brain functions, and the prediction of the evolution or outcome of certain diseases, either via classification of the subjects or via computation of diagnostic biomarkers.

Connectivities

The human brain is a really complex machine, different types of connections exist among the different regions and different modalities are being used in order to visualize and study them.

The study of connectivity of the brain is an important factor both το better understand how the human brain works and to delineate areas that need to stay untouched during a brain surgery to prevent severe counter-effects.

Structural (or anatomical) connectivity refers to the existence and structural integrity of tracts connecting different brain areas (i.e. white matter tracts connecting cortical areas/nuclei), while MRI and diffusion MRI are being used in order to study and visualize it.

Functional and effective connectivity are neuroimaging terms. Functional connectivity refers to the statistical dependence – correlation of the signal from different brain areas (usually with the use of resting state fMRI).

Effective connectivity is a bridge between the two different connectivity measures and brings in the element of causation (i.e. a signal, activation in one area directly causes a change or signal, activation or depression, in another area).

We can offer different connectivity analysis and visualizations based on the task at hand.

Epilepsy detection / prediction

 

Worldwide, more than 70 million people suffer from epilepsy, a neurological condition characterized by seizures that affect their quality of life. Despite the different treatments currently available, still 35% of the patients continue to experience seizures for the rest of their lives.

Different stakeholders can benefit from improved monitoring of epilepsy patients. The quality of life of epilepsy patients and their relatives can be improved substantially either by an increased feeling of security at home or a better treatment selection (decreased seizure frequency). Neurologists get access to more accurate and objective information from the ongoing treatments through the automated seizure diaries that allow better treatment selection. 

Such an automated monitoring system allows the pharmaceutical industry to select more efficiently the right type of patients for their clinical trials, which could lead to large cost savings. The developed methods can also be reused for other health applications by the medical device industry. Insurance companies can also see a decrease in expenses as a seizure warning system decreases the risk of injuries or post-ictal complications.

Automated seizure warning and detections systems can be used to improve the patients’ quality of life. Such systems can automatically detect ongoing seizures and alert the relatives. This way, both patients and relatives can feel reassured, knowing someone will help them when a seizure occurs in their everyday environment. Such applications require mobile measurements. Based on the type of the seizure that the patient exhibits, multimodal algorithms can be employed and data from different sources can be collected (e.g. Accelerometer, ECG, EMG). As an example, for the detection of seizures in a patient with absence seizures only the EEG signal is used, in patients with tonic clonic seizures a combination of EMG and EEG is optimal (possibly also ECG), whereas for frontal seizures ECG and EEG are employed. We offer different types of models and algorithms that can be used for accurate seizure detection and prediction.

Artificial Intelligence for the early prediction of Atrial Fibrillation

Definitions and epidemiology

Atrial fibrillation (AF) is a supraventricular tachyarrhythmia characterized by an uncoordinated electrical activation of the heart atria (the upper chambers of the heart). This irregular atrial electrical activity leads to an ineffective atrial contraction. AF can be classified based on its duration as paroxysmal (intermittent episodes of arrhythmia), persistent or permanent. AF is the most common arrhythmia in adults globally, thus it is a major cause of morbidity and mortality. It is estimated that AF’s prevalence is about 2-4% in the adult population. Increasing age is the most prominent risk factor for the development of AF along with several other comorbid risk factors such as diabetes mellitus, hypertension, coronary artery disease, chronic kidney disease and more. Modifiable risk factors such as smoking, physical inactivity and obesity also play an important role in the risk of AF development.

Clinical Characteristics and Outcomes

AF can have various clinical presentations from being asymptomatic or silent ,to symptomatic with variable severity of symptoms from palpitations and chest discomfort to more severe symptoms such as syncope and cardiogenic shock. Regardless of its clinical presentation the main cause of AF morbidity is its deleterious outcomes. AF is a major cause of stroke since it causes about 20-30% of all ischemic strokes. Moreover, a significant portion of AF patients (about 20-30%) will develop heart failure. Furthermore, AF predisposes to cognitive decline, depression and impaired quality of life. Finally, AF patients will have an increased annual hospitalization rate and, more importantly, an increased mortality rate since they are at a 1,5 to 3,5 fold increased risk of death.

Diagnosis and screening for Atrial Fibrillation

The diagnosis of AF requires rhythm documentation. An electrocardiogram (ECG) showing atrial fibrillation for at least 30 seconds is diagnostic for clinical AF. Since AF can be asymptomatic, however equally hazardous regarding its outcomes (eg stroke), screening and early diagnosis could be of great importance in reducing its associated morbidity and mortality. Various wearable devices ( wearable monitors, smartwatches, smartphones etc) can provide important data in the screening of AF.

Sepsis Prediction / Detection

Sepsis definitions

Sepsis is a life-threatening syndromic condition characterized by a new-onset organ dysfunction due to a disproportioned host response to infection. Sepsis is diagnosed as an increase of a minimum of 2 points in the Sequential Organ Failure Assessment (SOFA) score in a patient with infection. The SOFA score includes clinical and laboratory parameters that assess the cognitive, metabolic, circulatory and ventilatory function of the patient. Septic shock is the most devastating subset of sepsis, in which profound circulatory, cellular and metabolic abnormalities are associated with greater risk of mortality.

Sepsis epidemiology and burden of disease

Sepsis is a major global health problem and the World Health Organization (WHO) is calling for multidisciplinary actions to improve the morbidity and mortality due to sepsis. It is estimated that sepsis affects about 49 million people annually and causes about 11 million related deaths. The incidence of sepsis shows heterogenicity among the global regions, which tends to differentiate depending on their respective development status. Apart from the serious death toll, the burden of sepsis is further increased by its various social and economic implications, since sepsis is a major cause of increased length of in-hospital stay, readmission and disability.

Sepsis in the hospital setting

Of all sepsis cases, a substantial amount is Hospital Acquired (HA). It is estimated that HA sepsis represents 24% of the total in-hospital treated sepsis cases. This is attributed to Hospital-Acquired Infections (HAI), and is a major cause of mortality in the Intensive Care Unit (ICU) setting. A crucial factor that determines sepsis outcome is the time of intervention. Earlier medical intervention leads to decreased in-hospital mortality in sepsis patients. The development of tools that raise the awareness of healthcare providers could  significantly decrease the burden of in-hospital sepsis.

Technologies we use: