A simple reading task using 120 single-digit numbers can be used as a screening tool in the clinical setting to assess functional ocular motor difficulties in Parkinson disease (PD) that can have a profound impact on quality of life, a recent study found. Researchers assessed saccadic reading using variations of the King-Devick (KD) test, a rapid, single-digit, number naming test, as a way to assess the ability to make serial left-to-right ocular motor movements necessary for reading. They recruited 42 treated PD patients and 80 age-matched controls and compared their reading times with a variety of measures. They found:

• PD patients read about 20% slower than controls on all tests, and both groups read irregularly spaced numbers slower than regularly spaced numbers.
• Having lines between numbers to guide reading did not impact reading time in both PD and controls.
• Saccadic reading is slower in PD, but controls and PD patients are both impacted by visuospatial planning challenges posed by increased visual crowding and irregularity of number spacing.