Enigma of autism regression mechanistic pathways, clinical phenotypes, and early intervention implications

Table 6 Autism regression vs pathological mimics

Feature	Typical ASD regression	Pathological mimics
Language loss	Predominantly expressive	Receptive or global
Motor skills	Generally preserved	Progressive or episodic loss
Head circumference	Normal or accelerated	Decelerating or microcephalic
Course	Stabilizes after initial loss	Progressive or fluctuating
Social interest	Decreased (withdrawal)	May be preserved or significantly fluctuating
Systemic symptoms	Absent or mild gastrointestinal	Lethargy, vomiting, seizures
EEG findings	Often normal or focal	Marked epileptiform activity

ASD: Autism spectrum disorder; EEG: Electroencephalogram.