Systematic Data Acquirement

symptom.

(2) As mentioned above, the BI advocates to consecutively collecting the quantitative data. Regarding this, an experiment paradigm should be designed to satisfy the requirement of consecutive data acquirement by the multi-modality data collection tools.

(3) To support the systematic data analysis and fusion, the BI proposes an ontology based data fusion model -- Data Brain for integrating the multi-mode physiological, psychological and behavioral data, and recording the related data analysis process.

Meet Mini-international Neuropsychiatric interview (MINI) criteria for unidirectional depression; (6) Education level above junior high school; (7) Not accept any psychotropic drug therapy 2 weeks before experiment.

Exclusion criteria: (1) Severe physical illness and unable to complete the questionnaire; (2) Severe suicide risk; (3) Brain damage with organic disease such as epilepsy and have other brain disease with random discharge phenomenon; (4) Prior ECT treatment within the last three months; (5) In accordance with other psychiatric diagnosis criteria; (6) Alcohol or drug abuse within the last 1 year or psychoactive addiction in the past and at present.

The goal of multi-modality data collection is to collect the data which is capable of quantitatively representing the depression symptom. In our design, the portable devices are chose as the primary tools for collecting the multi-modality data since they are easy to be operated and able to detect the physiological or behavioral data in a long term.

Besides, the devices with big volume such as fMRI, EEG, and PET are also employed as data collection tools for measuring physiological signal. We also take the genetic factor into account to find some evidences of the genetic contribution to depression susceptibility. Ten categories of data collection methods are used to collect the multi-modality data, every depressive symptom is objectively evaluated by a corresponding single modality data. The depressive symptoms and the corresponding data collection methods are illustrated as follows:

(1) Mental disorder related depressive symptoms including depressed mood, anxiety psychic, thoughts and feelings of incapacity, fatigue or weakness related to activities [15]. According to the definition given by the Wikipedia, the MDD is a mental

disorder characterized by at least two weeks of low mood that is present across most situations. Thus, the principal clinical manifestations of the symptom focus on the disorder of the subjective emotions or feelings. The depressed mood indicates the negative emotions such as feeling of sadness, hopeless, helpless, and worthless. The anxiety psychic refers to the depressives feeling subjective tension and irritability, or worrying about minor matters. It is significant to recognize what kind of mental disorder does the patient belongs to, and further to quantify the severity level of the mental disorder. In order to do that, a self-rating tool for assessing the mood status named Q-Log is developed for self-rating the mental state by inpatients themselves. The subjects are required to self-rate their mental state just like writing a diary by using the Q-Log.

(2) Insomnia related depressive symptoms [29]. The clinical interviews assess the insomnia by observing the sleeping state in three scenarios: early in the night, middle of the night and early hours of the morning. Several sleeping events contain useful information for accurately depicting the insomnia symptoms, such as the subject nightly difficulty falling asleep, waking during the night, and is unable to fall asleep again if he/she gets out of bed. In our study, the sleep mattress equipped with micro-vibration sensor is employed as an insomnia monitor to detect the raw vibration signal in real time, the raw signal is further used to analyze the sleeping events and give a quantitative representation of insomnia.

(3) Slowness of thought and speech is one of typical depressive symptoms [30].

The clinicians always observe the voice speed during clinical interview. In order to quantitatively rate the slowness of thought and speech, we develop an android

application to record the interview conversation of clinician by using a lavalier microphone. The mic is clipped on the clinician’s collar so as to make the patient feel relax to talk his real thought. The speech data of patient is separated from the conversation and further used to analyze the voice speed and other phonetic features.

(4) Impaired ability to concentrate is one of manifestation patterns of retardation symptom [31]. A worse impaired ability to concentrate could cause interview difficult and even complete stupor to the patient. There are many evidences to manifest that the human attention could be recognized by the EEG signals. For example, NeuroSky company (San Jose, USA), a leading biosensor company, has developed an EEG chip with dry electrode located on forehead region [32]. The biosensor integrates an attention meter algorithm indicates the intensity of mental “focus” or “attention.” The output value of the algorithm ranges from 0 to 100. The attention level increases when a user focuses on a single thought or an external object, and decreases when distracted. Users can observe their ability to concentrate using the algorithm. In order to quantify the impaired ability to concentrate of patients, a portable EEG device equipped with the NeuroSky biosensor is used to collect the raw EEG signal and the attention index.

(5) Decrease in actual time spent in activities or decrease in productivity indicates that the patient spend few hours a day in activities, jobs, or hobbies. With the development of wearable device for detecting human body movement, this symptom is easy to be quantified using accelerator sensor [33]. In our study, we develop a diary behavioral data collection module using accelerator sensor and micro SD card. The module is required to be carried in a certain position of human body for a long term during daytime.

(6) The Cardiovascular disease (CVD) is one of methods to represent the anxiety somatic symptom [34]. Persons with depression are more likely to eventually develop CVD and also have a higher mortality rate than the general population. With the development of system-on-chip (SoC) technology, the cardiac arrhythmia could be measured by the portable or mobile ECG recordings. For instance, the NeuroSky has developed a small sized and low energy consumption biosignal SoC device, named CardioChip. It is a single chip solution designed to accurately measure, process and detect bioelectrical signal, such as ECG, by electrodes attached to the human skin surface. In order to quantify the cardiovascular symptom of patient, a portable ECG device equipped with CardioChip is adopted to collect the raw ECG signals of patients and analyze the cardiovascular abnormality.

(7) Cognitive dysfunction refers to deficits in attention, verbal and nonverbal learning, short-term and working memory, visual and auditory processing, problem solving, processing speed, and motor functioning. Cognitive complaints are core symptoms of acute MDD, and diminished ability to think or concentrate or indecisiveness are criterion items for the diagnosis of MDD [35]. Considering the cognitive dysfunction is high related with the brain functions, the brain signals measurement tools such as fMRI and EEG are also included in our experiment.

Combined with cognitive tasks, the cognitive dysfunction could be quantitatively evaluated.

(8) Genetic factors play important roles in the development of MDD, and may reveal important information about disease mechanisms [36]. Although the genetic factor could not be directly explained as one of depressive symptoms, as a systematic

data collection method, we also considered the genetic data collection and tried to investigate the MDD from the micro-aspect.

(9) The reliability of the quantitative evaluation method for depressive symptom needs to be validated by clinical evaluation criterions. A good reference for validating the objective method had better to be approved by authorities in clinical field. Regard this, the ICD-10 and the DSM-Ⅳ, which are common used in the clinical depression treatment around the world, could provide a reference result for validating the reliability of objective methods. The Structured Clinical Interview for DSM-5 (SCID-5), which is a semi-structured interview guide for making the major DSM-5 diagnoses, is common used in the clinical practice. It is administered by a clinician or trained mental health professional who is familiar with the DSM -5 classification and diagnostic criteria. In our study, the SCID-5 is employed as reference to validate the reliability of the objective evaluation methods for depressive symptoms.