Title: A new portable equipment for detection of psychophysical conditions: DDX
Author: prof. Alberto Rovetta N. AD-2

A. Antonini, A Rovetta., R. Fariello, M. Barichella, F. Lorini M. Canina, G. Pezzoli, A novel device in the evaluation of motor impairement in Parkinson Disease, Fifth International Congress of Parkinson's Disease and Movement Disorders, New York, October 10-14, 1998

A new portable equipment with detection of response time and psychophysical conditions in normal and exceptional environments also with virtual reality measurements with a fuzzy-based control system. It may be adopted for earth and space applications, because of its portability, in order to measure all the reactions in front of external effects.

The external effects require 1) the response to soundsand a soft touch of a button, 2) the touch of the finger in front of a virtual reality drawing of the finger itself, 3) pronouncing a word. The equipment is able to measure the reaction time of the person. The system obtains such goal using the following protocols:

  • - Fast Movement: starting from a fixed point of initial reference, the person must use the index finger to touch as fast as possible the target which measures the impressed force; in parallel, other parameters are measured, as the angular position, the speed of finger and the time of reaction.
  • - Movement with Virtual control: the person looks at a virtual image on a graphical display of his own finger and when he touches real target, then the virtual one changes color indicating that it has been caught up and this is the end of the test.

The other parameters are acquired from the button and these are: reaction time (defined as the delay time from acoustic signal of buzzer to the starting of pressure), speed (calculated from the starting point to the end point of button race) and force (by using a strain gauge).

The block (1) is the press button. This is the input patient interface and its function is to capture indirectly three basic information for diagnosis: the response time, the speed and the pressure of the fingertip. Effectively, it captures the start time of button pressure, the end time and the force impressed by using a strain gauge.The analog force signal is first amplified in block (2), after it is filtered by block (3) and then converted in a 8-bit digital form by block (4). All these three information are collected from block (6) which is the heart of the system and directs the informations flow among peripherals. Blocks (5,8) represents the medical operator interface to give commands and to read outputs. The block (6) manages all informations and stores them in block (11) if it is necessary. Tremor is also caught up by a very cheap switch accelerometer called “Tremor Sensor”. The block (10) performs fuzzy rules on acquired data and return diagnosis results that will be output on display (5). The audio unit, composed by a simple buzzer, is used to synchronize the patient actions in relation to the kind of test.

Future possible developments
Ability of transferring diagnosis through a remote communication interface in order to monitor daily the state of health of a patient.
The system is an intelligent-machine based on soft computing techniques. Its efficiency can be improved considering more examples for membership function calibration or, moreover, improving the response correctness by using a self learning technique.