Table 3.

Assessment of electroencephalography changes

Electroencephalography grading/Fischer classification (Nusinovici 1977 and Spehlman 1991) used in Hermant 1991; Pomier‐Layrargues 1994; Cadranel 1995; Barbaro 1998.
I	Irregular background activity (theta and alpha).
II	Continuous theta activity, bursts of delta waves.
III	Prevalent delta activity; polyphasic transients sharp and slow wave complexes.
IVa	Continuous delta activity; abundant sharp and slow wave complexes; electroencephalography reactivity present.
IVb	Slower activity (delta and some polyphasic transients); electroencephalography reactivity = 0.
IVc	Discontinuous activity with silent periods.
V	Flat.
Electroencephalography grading (Parsons‐Smith 1957) used in Dursun 2003.
A	Generalised suppression of alpha rhythm and its frequent replacement by faster potentials in all leads. The tracings in this grade are generally flat and featureless.
B	Alpha rhythm very unstable and disturbed by random waves at 5‐7 per second over both hemispheres. Rhythms most often seen over temporal lobes. In many cases with underlying fast activity.
C	Alpha rhythm still seen, but disturbed over both hemispheres by medium‐voltage 5‐6 per second waves. These occur in runs, are not paroxysmal, and do not usually block to eye opening although blocking may occur. Rhythms are particularly well seen over temporal and frontal lobes.
D	5‐6 per second rhythms seen in grade C are now constant in all areas and replace all other cortical activity recorded on electroencephalogram. Appearance of this abnormality in a patient presenting with only slight neuropsychiatric symptoms is very striking.
E	5 to 6 per second rhythms replaced by frontally preponderant bi‐lateral synchronous 2 per second rhythms, which spread backwards over hemispheres. At times, 6 per second rhythms might reappear, but special features of records are occurrence of these diencephalic discharges.
Electroencephalography grading (Kennedy 1973) used in Gyr 1996.
0	8 to 12 per second basic rhythm, mean dominant frequency > 8 per second, % theta < 20.
1	Sudden shifts between normal alpha frequency (around 9 or 10 per second) and slow substitutes (6‐8 per second); mean dominant frequency > 7 per second, % theta > 35.
2	Diffuse slow activity posterior alpha rhythm seen occasionally, mean dominant frequency 5 to 7 per second, % theta > 60.
3	Dominant slow activity in all areas, mean dominant frequency 3 to 5 per second, % delta 70.
4	Bilaterally synchronous, 2‐3 per second waves, predominating over frontal lobes and spreading backwards to occipital lobes; occasional short‐lived appearance of faster rhythms (5 or 6 per second) or voltage depression, mean dominant frequency < 3 per second, % delta 70.
Electroencephalography grading (Markand 1984) used in Van der Rijt 1995.
0	Background activity consisting of alpha rhythm.
1	Alpha rhythm with some scattered theta waves.
2	Background activity of theta activity intermixed with some delta and alpha frequencies.
3	Background of delta polymorphic activity of high amplitude with spontaneous variability.
4	Delta activity of relatively small amplitude.