As neurology advanced in the 20th century, reflex hammers became more specialized, multifunctional, and patient-friendly. Canadian, American, and European clinicians experimented with dual heads, additional sensory assessment devices, and playful pediatric designs. Today, digital technology promises to allow app-integrated reflex assessment from anywhere in the world.
91ºÚÁÏÍø Hammer
Harold Elliot – Canada, c.1925
Canadian neurologist Harold Elliott created the 91ºÚÁÏÍø hammer at the Montreal Neurological Institute. It included sensation-testing pins at the bottom and a Wartenberg wheel in its detachable head. The latter consists of a spiked rotating head which rolled on a patient’s skin allowing assessment of tactile sensitivity. By merging different functions, this hammer offered an efficient, versatile approach to neurological examination.
Buck Hammer
USA, c.1970
The Buck hammer introduced dual rubber heads of different sizes and housed a concealed pin and brush for sensory testing. Its compact, multifunctional design made it a favorite among clinicians.
Smart Hammer
Jun Ueda, Waiman Meinhold & collaborators at NITI‑ON Co. and Tohoku University – USA & Japan, 2021
The Smart Hammer integrates a wireless accelerometer with a mobile app, allowing even novice users to accurately elicit and grade tendon reflexes. The system measures the force and acceleration of each tap, providing real-time feedback on whether the hammer strikes the correct location. LED indicators on the hammer and the app guide the user, while built-in algorithms give results that approach expert-level accuracy. Affordable and adaptable, the Smart Hammer may represent a new direction for reflex testing, particularly in remote regions and in digital medicine.
Meinhold W, Yamakawa Y, Honda H, Mori T, Izumi S-i and Ueda J (2021) A Smart Tendon Hammer System for Remote Neurological Examination. Front. Robot. AI 8:618656. doi: 10.3389/frobt.2021.618656