TABLE 3.

Permutation Test

Brain Parameter	N	Imp.rate	Det.rate	P
VL	68	3%	15%	0.0001
WM	68	4%	13%	0.0001
HS	68	0%	1%	0.998
GL	68	1%	3%	0.0138
CY	68	1%	4%	0.0001
VR	68	6%	28%	0.0001

N represents the number of evaluable participants for each brain parameter, Imp.rate represents the percent showing improvement over time, Det.rate represents the percent showing deterioration, and P is the P‐value for the deterioration rate.

As improvement is most likely impossible; it may have been affected by radiologists' reliability. Det.rate represents the percent showing deterioration. P is the P‐value for the deterioration rate. Under the null hypothesis there was no true deterioration, the P‐value is defined as the probability of observing a deterioration rate as large or larger than the observed deterioration rate. The statistically significant level is usually set as 0.05. Only HS is not statistically significant. The remaining five parameters are statistically significant.