Study description
The method of the study was copied to a large extent from the two other published Life-Chart validation studies [9,10]. The substantial difference to these “template studies” is that in this study the Life-Charts were not documented with a PEN AND PAPER (P&P) Life-Chart form, but rather with an ELECTRONIC Life-Chart form, through the use of the PLC App. As with the template studies this study was a prospective, multi-site natural observation study. The validity analysis was done in the same way as in previous studies: Total Scores of the Inventory of Depressive Symptomatology, clinician-rated (IDS-C) and of the Young Mania Rating (YMRS) were cross correlated with Life-Chart ratings for functional impairment and mood.
The total study duration was 18 months for each sub-sample.
Subjects
This study analyses two sub-samples: 44 German-speaking and 10 English-speaking subjects. Patient networks within the German society for bipolar disorders facilitated the recruitment of the German sub-sample. This recruitment focussed on the number of patients. The recruitment of the English sub-sample was facilitated by the overseas internships of a doctoral candidate.
Patients were contacted in outpatient departments, on ward or at events of the German society for bipolar disorders with an invitation document giving an overview over the study. Subjects interested in study participation received detailed information with the informed consent document.
The study was conducted under approval of the ethical review committee of the University Hospital, Freiburg, Germany (Amendment of 06.03.2003 to Approval Nr. 114/99).
Inclusion criteria for the study (for both sub-samples) were a) DSM-IV diagnosis of BD I or II, BD not otherwise specified or schizoaffective disorder of bipolar type b) use of one of the versions of the PLC App in German or English respectively c) 18 years old or older and d) the ability to understand the goal of the study and to give consent.
Diagnoses were ascertained by the study team testing for DSM IV Criteria with standardized questions (SKID) whereby an MD confirmed all diagnoses. Despite broader diagnostic inclusion criteria, only patients diagnosed with BD I or II participated in the study.
Subjects were recruited from users of the PLC App. Nevertheless to ensure sufficient experience in the use of the PLC App, all participants received a standardized training in the use of the PLC App. A minimum of two months of Life-Chart usage was required before Life-Chart data was used for the study.
If questions or technical problems arose, subjects were able to report this and received immediate assistance by phone or by personal communication. Study data was entered in accordance with data protection regulations.
Procedures
The PLC App
The PLC App – for a more detailed description see [11] - is an electronic diary for patients with bipolar disorder. The rating period for the electronic diary is the one-day rating. Participants documented Life-Charts daily with the App. During the study, patients were able to record and edit data for the current and the previous day.
Clinical interviews and psychometric testing
Clinical interviews were used to assess the severity of manic and depressive symptoms. Psychometric Testing was done through the use of standardised questionnaires. The Inventory of Depressive Symptomatology, clinician-rated (IDS-C) [12,13] and the Young Mania Rating (YMRS) [14] were used to measure depressive and manic symptoms, respectively. The IDS-C rates depressive symptoms for a period of the previous 7 days. Some IDS-C items report the average symptom severity in that period (e.g. weight change). Most IDS-C items assess the maximum severity during that period. The YMRS rates manic symptoms within the last 48 hours.
The intervals between clinical interviews were 32 days on average. If patients were likely to show acute manic symptoms, they were contacted more frequently in order to capture the typically fleeting acute manic symptoms. The minimal interval between clinical interviews was 2 days, the maximum 205 days (median 23 days). Staff performed the clinical interviews personally or by phone due to the sometimes long distances to the outpatients. First clinical interviews with outpatients and clinical interviews with inpatients were always conducted in person, however. The staff was composed of assigned clinicians and doctoral candidates who successfully completed inter-rater reliability training. At the time of the clinical interviews, raters were blind to the Life-Charts patients entered into their devices.
Data collection
The subjects of the study provided Life-Chart data in the form of monthly Life-Chart reports printed from the PLC Cloud using personal computers.
In the German-speaking sub-sample first generation mobile devices (Palm OS) were used for Life-Chart documentation. In the English-speaking sub-sample, a variety of devices were used: PDAs, Smartphones and web browsers were all utilised to document Life-Charts (Figure 1). One patient without internet access sent Life-Chart data to the PLC Cloud using coded text messages entered into a mobile phone.
The PLC App was used daily to document Life-Charts. Except for the browser solution and the one patient who entered data via text messages, Life-Chart data needed to be transferred from the PLC App to the PLC Cloud with a patient initiated synchronization process. The entire data collection process is not part of this study.
The data source of this study was the monthly provided Life-Chart reports, exclusively. The PLC App enables the integrated printing of the Life-Chart information documented day by day into these monthly Life-Chart forms which are almost identical with the NIMH Life-Chart used in the prior Life-Chart validation studies.
Using this feature, the subjects of the study provided Life-Chart data in the form of monthly Life-Chart reports printed from the PLC Cloud using personal computers.
Data analysis
Thus data analysis was based on the paper versions of the Life-Charts – as with the template studies [9,10].
The assessed scores of the Inventory of Depressive Symptomatology, clinician-rated (IDS-C) and the Young Mania Rating Scale YMRS were correlated with the Life-Chart functional impairment ratings and mood ratings.
Furthermore the monthly Life-Chart report form closely resembles the paper Life-Chart forms used in the two aforementioned Life-Chart validation studies. This allowed for the use of exactly the same method for data analysis as with the template studies.
For the investigation of the validity of the PLC, Spearman Correlations were calculated. For calculation of the correlation between Life-Chart and IDS-C we examined the maximum depression scores (mood and “function”) documented on the Life-Chart within the 7-day period rated by the corresponding IDS-C. And in order to calculate the correlation between the Life-Chart and YMRS we used the maximum manic scores (mood and “function”) documented on the Life-Chart within the 48 hour period rated by the corresponding YMRS.
Life-Chart ratings outside of the assessment periods of IDS-C and YMRS ratings were not included in the study. Data was stored anonymously in MS Excel files and analysed with SPSS. Data access was limited to study staff, according to privacy protection regulations in Germany.