Grading Frequency Percentage 0 208 84.60% 1 23 9.30% 2 11 4.50% 3 4 1.60%

Table 2: Grading of Myoclonus; n=246; 0 No Movement; 1 Mild, Movement at wrist; 2 Moderate, Movement at arm only, elbow or shoulder; 3 Severe, generalized response or movement in one extremity.