Repeated measures tests for the change in total cystatin C concentration over time.

There were no significant longitudinal changes in CSF cystatin C concentration in ALS patients as a combined group, but fast progressors showed a moderate longitudinal decrease and slow progressors showed a moderate longitudinal increase. There was a significant interaction between the change in cystatin C concentration over time and patient progression speed (fast versus slow progressors) as listed in Time.
*Progression speed column (p = 0.032). Asterisk indicates statistical significance at p<0.05.