Devices, methods and systems for measuring pulse wave velocity

An apparatus, comprising:

• a light source system configured for providing light to a target blood vessel adjacent to an outer surface of the apparatus;
• an ultrasonic receiver system configured to receive ultrasonic waves generated by the target blood vessel responsive to the light from the light source system;
• a first ultrasonic sensor at a first location corresponding to a position along the target blood vessel;
• a second sensor at a second location corresponding to a different position along the target blood vessel;
• and
• control means for:
• receiving first sensor signals from at least the first ultrasonic sensor of the ultrasonic receiver system, the first sensor signals comprising ultrasonic receiver signals;
• estimating one or more blood vessel features based on the first sensor signals;
• receiving second sensor signals from the second sensor, the second sensor signals corresponding to the blood vessel;
• estimating a pulse wave velocity based, at least in part, on the first sensor signals and the second sensor signals;
• and
• estimating blood pressure based, at least in part, on the one or more blood vessel features and the pulse wave velocity, wherein the apparatus comprises an ear bud, headphones or an ear clip configured to be worn by, or attached to, a person.

A method, comprising:

• receiving first sensor signals from at least a first ultrasonic sensor of an ultrasonic receiver system, the first sensor signals comprising ultrasonic receiver signals corresponding to ultrasonic waves generated by a blood vessel responsive to light from a light source system, the first ultrasonic sensor positioned at a first location corresponding to a position along the blood vessel;
• estimating one or more blood vessel features based on the first ultrasonic receiver signals;
• receiving second sensor signals from a second sensor, the second sensor signals corresponding to the blood vessel, the second sensor positioned at a second location corresponding to a different position along the blood vessel;
• estimating a pulse wave velocity based, at least in part, on the first ultrasonic receiver signals and the second sensor signals;
• and
• estimating blood pressure based, at least in part, on the one or more blood vessel features and the pulse wave velocity.