LTap; A Portable Protocol for Measuring Sensorimotor Synchronization
Abstract
The aim of the study has been to design, develop and validate a reliable, portable, and user friendly protocol to measure sensorimotor synchronization (SMS). SMS is used to indicate learning disabilities and diseases like ADHD, dyslexia, etc. It is typically studied by index finger tapping to a sequence of isochronous stimuli.SMS testing is currently carried out in the laboratory where the MATTAP protocol represents a gold standard for such measurements. Different approaches have been taken to develop SMS testing on smartphones, but they have shown limitations with respect to the required accuracy or simple data extraction. A new protocol, LTap, has been developed in this study. LTap is based on existing well documented test principles. The goal of the protocol is to combine the strengths of the MATTAP protocol and the previously developed smartphone protocols, but avoid most of their weaknesses.LTap uses dedicated hardware in an embedded circuit, controlled by an Android smartphone. The raw data from the measurements are transferred by Bluetooth radio to the Android smartphone where they are stored, displayed and possibly exported for further analysis. LTap facilitates a simple and efficient data analysis, where the recorded data are stored as comma separated values(CSV). This format is also used, by amongst others, MATTAP for SMS analysis. Data from LTap therefore also can be analyzed by these protocols. Such reuse of software may lower the threshold of converting to LTap for the performance of SMS measurements.The reliability of the protocol has been validated in two different ways. First, an SMS sequence was recorded simultaneously by the embedded circuit and a high speed camera and then they were correlated. The results from this correlation validated the accuracy of the embedded circuit to be within the stated requirements, matching also the accuracy of MATTAP. Thereafter, a pilot test-retest study was performed, which replicated the results of previously published laboratory experiments. The approach of using dedicated hardware to measure SMS may be a solution used in the future. The bluetooth interface allows simple interfacing to most smartphones. The drawback of using embedded hardware is the difficulties in distributing the protocol. LTap requires additional physical components, and a ready-to-use protocol can therefore not be downloaded from the web such as other smartphone based protocols. However, the simple design and use of cheap parts allows the circuit to be mass produced, and it can thus sold be relatively cheap.LTap has several advantages compared to existing protocols. The system is accurate, portable and has a simple user interface. None of the existing protocols can combine all these features. LTap may therefore expand the areas for performing SMS analysis. One of these areas could be to screen all pupils in first grade of elementary school for learning disabilities. This may help to provide an earlier intervention for adapted teaching to pupils with learning disabilities. Before this kind of intervention can be done, a larger test-retest study should be performed. If LTap is validated by a larger test-retest study, it may have the potential to become the new gold standard for measuring SMS. The results found in this thesis will be submitted to the journal Behavior Research Methods.