TABLE 3.

Distribution of CSF metal/metalloid levels (median, 25th, and 75th percentile) by disease onset.

Metal/metalloid (μg/L)	Control N = 9 Median (IQR)	Spinal onset N = 20 Median (IQR)	Bulbar onset N = 9 Median (IQR)
Cu*	129.7 (95.55–258.7)	78.11 (70.71–124.1)	93.37 (66.78–191.7)
Ni*	2.23 (1.84–3.73)	4.21 (3.27–6.23)	3.30 (1.65–3.64)
Hg	0.30 (0.22–0.55)	0.34 (0.20–0.41)	0.23 (0.14–0.38)
As	0.90 (0.59–1.55)	0.67 (0.59–1.01)	0.84 (0.57–1.59)
Mn	2.07 (1.39–2.85)	2.76 (1.34–3.91)	1.71 (1.48–2.01)
Fe	283.0 (197.8–371.9)	193.2 (151.5–274.3)	254.5 (177.6–330.2)

*Mann–Whitney test shows significant difference between Spinal and Control groups for Cu (p = 0.04) and Ni (p = 0.02), as well as between Bulbar and Spinal groups for Ni (p = 0.03).