Accents in Western notation are quantitative and correspond to the diplē (διπλή) or dyo apostrophoi (δυο ἀπόστροφοι) in Byzantine Round notation. The Sankt Gall notation modificates the basic forms by an episema — a horizontal stroke. The episemata can also be used in doubled form, so that some singers interprete the simple form as two times of the usual note and for times for notes with two episemata. Others refuse this very strict rhythmic interpretation. The Lorraine scriptoria which developed a more analytical form of notation, use an additional letter that is written under the prolonged neume. A doubled form is not specified.
The accent in Lorraine notation is indicated by the letter «a» for «augete»:
The accent in Sankt Gall notation is horizontal stroke called «episema» - in this combination the 1st, 3rd & 4th note have an accent and the two last «episemata» replace the usual «puncti»:
The third element of «tristropha» is prolonged by an «episema»:
Sankt Gall notation also uses double «episema» or «episemata» as here on the last note: