An Exploration of Apathy and Impulsivity in Parkinson Disease

Table 6

Forced linear regressions with BIS-11-derived factors 1 to 5 as the dependent variables.

BIS-11-derived factor	Independent variables contributing to the variance	Statistic
Factor 1: “inattention”	UPDRS complications of therapy; HADS anxiety; HADS depression	𝑅^2=0.27; 𝑃<0.001; constant 𝐵=6.98 (SEB 0.62)
Factor 2: “impetuosity”	UPDRS complications of therapy; HADS anxiety; NPI disinhibiting	𝑅^2=0.38;𝑃<0.001; constant 𝐵=6.59 (SEB 0.49)
Factor 3: “personal security”	HADS anxiety; Younger age of onset; Shorter duration of disease; NPI aggression	𝑅^2=0.40;𝑃<0.001; constant 𝐵=6.32 (SEB 1.71)
Factor 4: “planning”	Younger age of onset; NPI irritability	𝑅^2=0.17;𝑃<0.001; constant 𝐵=7.36 (SEB 1.08)
Factor 5: “future orientation”	NPI disinhibition; HADS anxiety	𝑅^2=0.12;𝑃=0.004; constant 𝐵=4.47 (SEB 0.28)

HADS: Hospital Anxiety and Depression Scale.
NPI: Neuropsychiatric Inventory.
UPDRS: Unified Parkinson’s Disease Rating Scale.