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Figure 10. Main overall VAS score with 95% CI by visit (left) and by stimulation mode (right)
Secondary Effectiveness
The following table compares responder rates for burst stimulation versus tonic stimulation, where
"responder rate" is defined as a decrease in the overall daily VAS score from baseline by at least
30%. A total of 69 subjects (69%) responded to tonic stimulation, burst stimulation, or both.
Responder rates are 60.0% with burst stimulation and 51.0% with tonic stimulation. A cross-
tabulation of responders for burst stimulation versus tonic stimulation shows numerically more
subjects whose VAS score decreased by at least 30% with burst stimulation than with tonic
stimulation (18 versus 9). However, this difference was not statistically significant (
p
=0.083).
Table 30. Responder rates (decrease of
≥
30% from baseline) for overall daily VAS score
Overall Responder Rate
Percent of burst subjects (n/N)
60.0% (60/100)
Percent of tonic subjects (n/N)
51.0% (51/100)
Cross-Tabulation of Responders by Stimulation Mode
Stimulation mode
Tonic
Responder
No
Yes
Burst
No
31/100 (31.0%)
9/100 (9.0%)
Yes
18/100 (18.0%)
42/100 (42.0%)
p
-value (Burst vs. Tonic)
0.083
m
m
McNemar’s test