Modern Mechanix posted an interesting newspaper snippet from the year 1929: This Instrument Will Register Body Reactions of Student Piano Player.
For some reason these type of devices always look a bit creepy to me…
The article reads:
A NEW device has been patented by Dr. Kurt Johnen, Berlin piano pedagogue, which records the motions and bodily reactions of a piano player to determine if the selection is being properly interpreted. A lady is pictured being examined by the device. A pneumatic belt records the change of the circumference of the chest, pneumatic cuffs about the upper arms control the changes of muscle tension, through a hose is recorded the rhythms of respiration and another hose transfers the strength of touch. Dr. Johnen expects this device will aid him in instructing his pupils in interpretation.
Link via Boing Boing Gadgets