Table 4.

Gulf War-exposure indices, Parkinson’s disease-like (PD-like) symptoms, and intracranial volume-adjusted (ICV-adjusted) basal ganglia volumes by group in the study of Gulf War veterans (N = 293) recruited in 2002–2017

Symptoms	Participants
	total (N = 293)	with KGWI (N = 122)	with CMI (N = 234)	controls (N = 48)
Gulf War-exposure indices (M±SD)
Nisenbaum indexa	3.3±2.2	4.1±2.0f	3.7±2.1f	1.9±1.9
Steele indexb	2.0±1.8	2.3±1.7f	2.2±1.8f	1.1±1.3
Parkinson’s disease-like symptoms
motorc [n (%)]	70 (24)	35 (29)g	69 (30)g	0 (0)
non-motord [n] (M±SD)	5.9±3.2	7.4±2.1f	7.1±2.3f	1.2±1.4
Adjusted basal ganglia volumese	2.13×104	–1.94×107	–1.28×107	1.14×108
	(3.11×108)	(2.54×108)g	(2.83×108)g	(3.16×108)

Abbreviations as in Table 3.

^aA sum of responses regarding the frequency of taking PB pills, using cream or liquid and/or powdered pesticides on skin, and the presence or absence of experiences that lead the veteran to believe s/he was exposed to chemical agents while in the Gulf region, based on Nisenbaum et al. [30].

^bA sum of responses regarding the frequency of taking PB and being within 1 mile of an exploding SCUD missile among the veterans who served in Iraq and/or Kuwait, and a sum of responses regarding the frequency of wearing pesticide-treated uniforms, using cream or liquid and/or powdered pesticides on skin among the veterans who did not serve in Iraq or Kuwait, based on Steele et al. [5].

^cTremors and/or shaking.

^dThe total number of non-motor symptoms (i.e., feeling dizzy/light headed; fatigue; problems getting to/staying asleep; night sweats; blurred or double vision; pain in joints, muscles, or overall body pain; feeling anxious; feeling depressed; problems concentrating; problems remembering recent information) endorsed.

^eAdjusted for intracranial volume (ICV).

^fSignificantly different from controls: p = 0.01.

^gSignificantly different from controls: p < 0.001.