A suspected case:	Reported head nodding in a previously normal person; head nodding was defined as repetitive, involuntary drops of the head to the chest on two or more occasions. This case definition is used at the community level.
A probable case is a suspected case with:	Both of the following major criteria:
	-Age at onset of nodding between 3 and 18 years old
	-Frequency of nodding 5 to 20 per minute
	Plus at least one of the following minor criteria:
	-Other neurological abnormalities (cognitive decline, school dropout due to cognitive/behavioural problems, other seizures or neurological abnormalities)
	-Clustering in space or time with similar cases
	-Triggered by food and/or cold weather
	-Stunting or wasting
	-Delayed sexual or physical development
	-Psychiatric symptoms
A confirmed case is a probable case plus a documented nodding episode that is:	Observed by a trained healthcare worker or recorded on film or on EEG/EMG.