Lead (Pb) is a neurotoxic substance. While it is widely understood that Pb exposure in early childhood adversely impacts neurodevelopment and intelligence, other aspects of cognition that are negatively affected, and the neuroanatomy and neurophysiology underlying Pb-related cognitive impairment are not widely appreciated by clinicians. This critical review gives a broad synopsis of the current literature in the field. The means by which Pb enters the body, crosses the blood-brain barrier, alters brain structure and function, and consequently impacts measurable aspects of cognition are reviewed. We detail research relating exposure to Pb at various levels in early childhood to deficits in IQ, academic achievement, executive functioning, and cognition in general. Clinical disorders associated with early Pb exposure, common and uncommon routes of environmental exposure, and potential confounding variables are discussed. We discuss methods of statistically accounting for these issues in the context of potential means of relying upon existing research and specific individuals' known blood Pb levels to make reasonable calculations regarding Pb-related compromise of intellectual functioning for individuals in clinical settings.
Keywords: Academic achievement; IQ; Pb; cognition; lead.