This study compares four nasalance measures computed as ratios between the amplitude of signals recorded with accelerometers and microphones. Two new measures based on RMS amplitude differences between the nasal signal and either the vocal folds vibration signal (LND) or the oral acoustic signal (OND) are introduced. Measures were compared on a total of 584 utterances produced by four native French speakers. Results show that (1) all measures separate nasal from oral consonants, (2) the different experimental setups cannot be considered equivalent, (3) difference-based measures appear to better describe the time course of nasality than ratio-based measures.