I take my grandmother to physical therapy three times a week for rehab after having a stroke. I notice the therapists always use a handheld device that looks like an air stapler to measure Nana’s right foot that was affected by the stroke. What does this tell them?

It sounds like you are describing a dynamometer. This handheld tool is a device used to measure muscle force. Many patients suffer from hypertonia after a stroke. This means the muscles are hyperactive. A group of muscles commonly affected include the gastrocnemius (large calf muscle) and the soleus muscle (a smaller muscle that forms part of the calf).

The dynamometer helps evaluate speed and excitability of the ankle plantar flexor muscles. Plantar flexion is the movement of the foot away from the face (pointing the toes). The therapists may be measuring the quality of the plantar flexor muscle reaction when the (ankle) joint is moved. This particular measurement is important to track before and after results of treatment and to assess the patient’s overall recovery from a stroke.

Here’s some information that might help explain what’s going on. If you’ve ever held an older infant, you know when placed in an upright position, they tend to bounce on their feet. That’s a reflex. Pressure on the balls of the feet causes the ankles to plantar flex (toes point down). Eventually, the nervous system matures a bit more and this reflex is no longer so dominant. Now the child can put the foot down on the ground and walk without the plantar reflex causing bouncing.

This reflex seems to come back in adults who have had a cerebrovascular accident (CVA) (stroke). Damage to the brain from the stroke results in muscle hypertonicity (increased muscle tone). The increased tone and abnormal reflex reactions make walking normally difficult.

Physical therapists are often key members of the rehab team helping people with strokes to recover movement and function. Finding ways to reduce the excess tone and keep from triggering the plantar flexor reflex is an important part of the program. And in order to know if the treatment is working, it’s necessary to measure the muscle tone and reflex response from before to after intervention.

This is a likely explanation for what’s going on. But feel free to ask the therapist to explain what he or she is doing and why. The information may help you understand what has happened to your grandmother and may even help her understand her own condition. Patient (and family) education is a key ingredient to a successful rehab experience!