| Terms |
Definitions |
| Treatment delay (TD) |
The period between the initial onset of ISs and the start of ACTH therapy |
| Assessment of developmental deterioration (for ages 0–5 years / for ages >5 years) |
None: normal development / regular school |
| Mild: decreased smiling, alertness and interest in the surroundings / regular school with support |
| Marked: diminished eye contact, response to sound vocalization, and object manipulation / special education school |
| Severe: absent smiling, eye contact, interest, manipulation and spasticity or hypotonia / uneducable |
| Hypsarrhythmia paroxysms (HPs) |
High-voltage (generally >200 μV) slow waves with variable amplitude; spikes and sharp waves from many foci, and varying with time; and a lack of synchrony, with a generally chaotic appearance |
| Countable hypsarrhythmia paroxysm index (cHPI) |
Number of HPs in NREM sleep divided by NREM duration (min) |
| Durational hypsarrhythmia paroxysm index (dHPI) |
Total duration of the HPs during NREM sleep calculated as the percentage of NREM sleep time |
| TD, treatment delay; ISs, infantile spasms; ACTH, adrenocorticotropic hormone; HPs, hypsarrhythmia paroxysms; cHPI countable hypsarrhythmia paroxysm index; NREM, non-rapid eye movement; dHPI, durational hypsarrhythmia paroxysm index. |
