Two point vibrotactile spatial resolution for a pulse burst stimulus: tangential versus perpendicular excitation

The paper presents an experimental study of the effect of the pulse repetition period and duty cycle on the two point vibrotactile spatial discrimination for perpendicular and tangential excitation. An array of piezoceramic vibrators is used to measure the two-point discrimination distance on the index finger on 14 subjects. The excitatory waveform considers pulse repetition periods between 1/25 s and 1/500 s, two different duty cycles (50% and shorter). Results show that discrimination distance decreases for larger pulse repetition periods in both cases: perpendicular and tangential excitation. It is also found that discrimination distances are smaller for tangential relative to perpendicular excitation for pulse repetition periods below 1/50 s