EEG | Normal background | - Interictal: Lack of generalized spike-wave discharge on sleep recording
- PPR at low frequency photic stimulation (suggest CLN2 disease)
| - Ictal: Recorded myoclonic event without EEG correlate
- Interictal:
- Hypsarhythmia
- Generalized slow spike-wave (<2.5 Hz)
|
Development at onset | | - Speech delay at time of diagnosis
- Moderate to profound ID
| |
Imaging | | | - Significant neuroimaging abnormalities
|
Course of illness | | | - Neurocognitive regression
|
Syndrome without laboratory confirmation: In resource-limited regions, at a minimum, a sleep EEG showing generalized spike-wave is required to make this diagnosis |