R.C. van Lummel and H.J. Busser

McRoberts b.v., The Hague, The Netherlands

Overview. Home monitoring helps the medical specialist in the diagnosis at an early stage of illness and supports in treatment and rehabilitation. For these purposes there is the need for a highly portable diagnostic system that can measure objective data in the natural environment of a patient at a cost-efficient rate. The heart of DynaPort is the monitoring of the Activities of Daily Living (ADL), in short: ADL monitoring. ADL describes the basic activities of self care, such as getting up, moving about, lying down, sitting etc. The making of the portable "ADL Monitor" was accomplished by utilizing the unique and innovative know-how as obtained through the Eureka project "DynaPort" (see Veltink & van Lummel, 1994). The DynaPort project has developed a number of successful methods for monitoring motor activity on the move. Outcome measures are based on objective measurements of ADL and benefit treatment evaluation and aftercare.

Features. DynaPort monitors are electronic data recorders that are small and lightweight, easy to wear and robust, and do not hamper a patient in daily activity. A great strength of the DynaPort monitors is that they were developed in co-operation with their users, the medical specialists. The systems measure up to 24 hours continuously, thereby gathering a large amount of data with which powerful outcome measures are produced. Personal calibration enables high reliability of analysis. The system is easy to use, no technical background is required. Starting a measurement without computer is easy.

Benefits. The ADL Monitor gives the medical specialist a new method for diagnostics, treatment, evaluation, and for aftercare. Objective measures of ADL are collected continuously over a certain period, revealing information on the patient outside the hospital and under natural circumstances. A specialist can follow a patient in his own habitual activity, at work, at home, or at leisure activities.

Typical measurement setup. Subjects wear the data recorder in a DynaPort belt. From the belt or backpack a lead goes down to the upper leg, where an optional sensor is mounted on a strap or a pair of shorts. After data collection, the data are downloaded on a PC, analysed and stored in the patient database.

Typical report generation. After storing the measurement files, reports can be generated. The reports contain powerful outcome measurements that benefit treatment evaluation. Outcomes as with respect to the overall motor activity, movement time, movement intensity, locomotor activity, resting activity, in and out bed times, times in bed, turn while lying down in bed, and the times one gets up at night give a comprehensive though compessed ADL evaluation of the measurement. Outcomes are presented of the overall measurement, plus specification of day and night time periods. A parameter set can be exported to ASCII for statistical analysis of groups of patients. A measurement history is included for a single patient for the evaluation of treatment progress.

Preliminary results. Within the DynaPort project, the study of Bussmann et al. (1995) proves that the method for discriminating postures is reliable in the case of healthy adults and amputees. The first validation study with children is encouraging as well. The motor activity profiles of 21 children in the age of 1.5 to 9 years have been registered at the "Kinderzentrum München" in cooperation with Dr. R. Blank. The obtrusiveness of the system proved to be minimal. The first impressions of the classification results are positive; postures and locomotion were to a large extent detected correctly. The video recordings accompanying these measurements are currently being compared with the classification results.

Prospects. It is likely that the ADL monitoring method can be applied in a wide range of applications for all types of patient groups, children, adults, elderly, and disabled. Especially encouraging to us are the clinical studies that are recently performed. One is the Hyperactivity project at the Kinderzentrum München on motor activity in children with the diagnosis ADHD, of which the variety of postures and motor activities is enormous, and stimulates to further extend the ADL classifications with child and play ground activities. In the Drug Profiling project a method is studied double blind for the clinical evaluation of the (side) effects of drugs on motor activity at home. The results are promising and the first data indicate that, the statistical evaluation is pending though, a dose of lorazepam causes a reduction of overall motor activity, a reduction of turns while lying at bed at night, and an increase of time spent in bed at day. ADL monitoring projects on elderly people and backpain patients are currently planned. In the latest patient study we did a comparison of the effects of two different work conditions to a chronic back pain patient measured during work. We compared the objective recordings using the reduction and provocation analysis that the IVAS (Heliomare) made. We were able to identify differences that explain the subjective pain scores of the patient.

Veltink, P.H.; van Lummel, R.C. (1995). Dynamic Analysis Using Body Fixed Sensors, Congress book, McRoberts BV, The Hague.
Bussmann, J.B.J.; Veltink, P.H.; Martens, W.L.J.; Stam, H.J. (1995). Ambulatory monitoring of mobility-related activities: the initial phase of the development of an activity monitor. Europ. J. Phys. Med. Rehabil.

Paper presented at Measuring Behavior '96, International Workshop on Methods and Techniques in Behavioral Research, 16-18 October 1996, Utrecht, The Netherlands