 He designed the Trömner reflex hammer, a popular reflex hammer that is used for evoking cutaneous and myotatic responses.His name is also associated with "Trömner's reflex" of which, with the fingers of the patient partially flexed, the tapping of the volar aspect of the tip of the middle or index finger causes flexion of all four fingers and thumb.This phenomenon is associated with pyramidal tract lesions with moderate spasticity.