Unchanged gastric emptying and visceral perception in early Parkinson's disease after a high caloric test meal

Delayed gastric emptying (GE) is a frequent non-motor feature in Parkinson´s disease (PD). This prospective study (clinicaltrials.gov Identifier NCT01518751) investigated GE and visceral perception in early motor phase PD patients in comparison to age-matched and younger controls. In addition, the effect of Levodopa on GE was assessed in healthy aged controls. 16 PD patients (Hoehn & Yahr 2), 11 sex-/age-matched Ctrl1 and 10 young, male Ctrl2 subjects were subjected to a high caloric (428 kcal) ¹³C-Sodium Octanoate breath test strictly OFF dopaminergic medication. Visceral appetite sensation was monitored using visual analogue scales (VAS). GE was similarly studied in 7 controls ON/OFF oral Levodopa. GE was not altered in PD patients compared to age-/sex-matched and younger controls (p = 0.76). Subjective appetite perception was not altered in the PD group in comparison to Ctrl1, but was significantly higher in Ctrl2 subjects (p = 0.02). 100 mg oral Levodopa/25 mg Benserazide significantly slowed GE by 18 % among healthy controls (p = 0.04). In early motor stage PD OFF dopaminergic medication, there was no GE slowing after a high caloric test meal. Levodopa, however, caused a robust GE slowing in healthy aged individuals. Our data indicate that clinically relevant GE slowing in early PD is related to the iatrogenic effect of dopamine treatment. Subjective appetite perception is not affected in this disease stage. This data add to the understanding of gastrointestinal symptoms in early motor stage PD and highlight the influence of dopaminergic medication.