The present invention is in the field of an improved wearable ultrasound device for signalling changes in human or animal body, and use of such a wearable device for signalling over a prolonged period of time. In an example the changes occur in a bladder. Such is especially relevant for elderly persons, women after delivery of a baby, lesion patients, dement people, and others, have a difficulty to control functioning of the bladder, and to be at the toilet on time to urinate. This (partial) incontinency is highly inconvenient and may also be an item that is not addressed at all.
