Classification and Serial Evolution of PLEDs

Background and Purpose: P e rio dic la te ra lize d ep ilep tifo rm d is c ha r g e s (P LEDs ) a re d e fin ed a s s pi k es o r s ha rp wa ve s o ccurri n g a t a n a pprox ima te ly r egul a r in te rva l. P LEDs a re s ub d ivid ed in to P LEDs p roper a nd P LEDs p lus in Re iher ’s c la s s ific a tio n , bu t s in c e this d o e s n o t s u ffic ie n tly r e flec t the p le o mo r p his m o f P LEDs , we p ro p o s e a n ew sub c la ssi fic at io n s ch e me o f P LEDs , a nd d is cuss the re la tio nsh ip betwee n the m a nd c lin ic al p rognoses. Met h ods: Thir ty-s eve n p a tie n ts who ha d a t le a s t two a va ila ble EEGs wer e in cl u ded in this s tu dy. Ea ch p at ien t ha d s tr uc tur a l bra in les io n s id e n tifie d in br a in CT/M RI: 237 EE Gs fr o m 37 p a tien ts wer e r eviewe d a n d the p a tte rn s of P LEDs we re c la ssi fied by elec tro enceph a lo graph ic c ha ract e ristic s ba s e d o n Reihe r’s c la s s ific a tio n . P LEDs p ro p er o f c la s s 3 we re s u bc la s s ifie d in to fo ur c a te g o ries : (1) s imp le , (2) ben ig n , (3) vig o ro u s , a n d (4) s up p re s s ed . R esul t s: M ost o f the P LEDs tha t s ta rt e d with the vig orous o r s uppressed p a tte rn o f c la s s 3 evo lved in to the si mp le o r be ni g n p at te rn o f c la ss 3 a nd s ub s eq u ent ly c ha nged into c la s s 1 o r c la s s 2, fin a lly in ter min g lin g with the nei g hbo ri n g ba ckground wa ve s. P LEDs tha t s ta rte d with the be ni g n o r s imp le p at te rn o f c la ss 3 ra pi dly c ha nged in to c la s s 1 o r 2. P a tien ts s ho win g the be n ig n o r s imp le p a tte rn o f c la s s 3 e xhibite d a be tte r c lin ic a l p ro g n o s is . C oncl usi ons: P LEDs ha ve five d is tin c tive c la s s e s , a n d o ve r time the y e vo lve fro m ma lig nant P LEDs p lu s to be ni g n P LEDs p roper be fo re fin al ly d is appeari n g. It a ppears tha t tho se o f c la ss 3 ha ve mo re diver se p at te rns, with the vig orous a nd s uppressed p at te rns be in g the mo re ma lig nant f orm s o f P LEDs in this c la ss. J Clin Neurol 2(3):179-185, 2006