Verily submitted the letter of intent for a drug development tool (DDT) for the virtual motor exam for Parkinson’s disease. The device measures a change in digitally assessed parameters of a subset of Parkinson’s disease motor signs from the MDS-UPDRS Part III (motor examination) through a smartwatch (Verily’s Study Watch), according to the FDA letter.

According to the FDA’s findings, the examinations provided by Verily are “limited in their capacity to evaluate meaningful aspects of concepts of interest that are relevant to the patients’ ability to function in day-to-day life.”

The FDA said a change in rigidity or finger tapping can’t be directly interpreted as meaningful to patients. On the other hand, a change in speech, eating and dressing does represent meaningful change. Further, the remote assessment providing an algorithmic representation of changes raised additional concerns with the FDA, which pointed to the (in)ability to interpret what are considered meaningful changes in a patient’s ability to function.

Specifically, the FDA pointed out there is a lack of clarity in how the change in the digital signature for finger tapping could be interpreted as representing a meaningful change in function.

“For these reasons, when evaluating drug efficacy in Parkinson’s disease, the FDA prefers content that is more representative of daily life functioning (e.g., consistent with the MDSUPDRS Part II or other similar instruments),” the FDA concluded.

Verily’s Study Watch still has an FDA clearance to function as an irregular pulse monitor and an ECG reader.