I've had excellent success with the one from Zygo. The trick is to stay with the headset mic and not use the lavalier because it's usually not strong enough for pALS.
In clinic today, after trying several voice amplifiers across the price spectrum and both wired and wireless, a patient identified the Luminaud Spokeman as the one he found clearest with the least feedback or cutout (Bulbar onset so small and portable is a priority for him). He then asked me "If money was of no object, what is the best, small, high quality, no feedback and no cut-out amplifier there is?". Knowing I have a limited arsenal, I thought I would put the question out there.
What have others found?
Thank you!John