TABLE 6.

MEP Findings and Postoperative Muscle Strength of the 74 Lower Extremity Muscles in the 39 patients With Tumors Involving the Cervical Enlargement.

	Muscle strength
MEP findings	Worse	Unchanged/improved	Sum
No response	4	24	28
Negative MEP findings:
Stable	2	19	21
Appeared after initial absence	0	7	7
Temporarily disappeared or declined to <20% baseline amplitude with recovery at the end	0	3	3
Subtotal: negative MEP	2	29	31
Positive MEP warnings:
Declined to <20% baseline amplitude	2	3	5
Disappeared	6	4	10
Subtotal: positive MEP	8	7	15

Positive Predictive Value was 0.53 (=8/15) and Negative Predictive Value was 0.94 (=29/31)