Identifying PD in the earliest stages may be key to effective disease modification. The value of knowledgeable informant observations to identify early stage PD is unknown.

We conducted a survey of persons who reported knowing a person with PD (PwPD) in the years before diagnosis through the online Fox Insight Study.  

1,073 knowledgeable informants (338 spouses, 16 parents, 105 siblings, 447 children, 69 friends, and 98 other) completed the survey, of whom  93% reported at least one PD-related feature in the PwPD prior to diagnosis, most often in the 3 years before diagnosis, but >10 years before in some. Tremor or shaking was reported by 41%, reduced sense of smell ( 30%), smaller handwriting (28%), worsening balance (28%), softer voice (26%), reduced facial expression (24%), moving more slowly (24%), shuffling or small steps (24%), difficulty staying asleep at night (24%), acting out dreams (23%), constipation (23%), nocturia (22%), anxiety (20%). Features reported by <20% included reduced arm swing when walking, falling and difficulty using new gadgets. 

Spouses (97%) and children (95%) were more likely to report pre-diagnostic features compared to  siblings (91%), friends (81%) or other family members (75%). Compared to children, spouses more often reported reduced sense of smell. (48% vs 24%), acting out dreams (30% vs 26%). Children reported more often than spouses worsening balance (39% vs 15%), shuffling or small steps (30% vs 15%), or less interest in leaving home (25% vs 14%).

Data collection is ongoing and additional data will be presented.