By Christian Jarrett

Studying people who have brain damage or illness has been hugely important to progress in psychology. The approach is akin to reverse engineering: study how things go wrong when particular regions of the brain are compromised and it provides useful clues as to how those regions usually contribute to healthy mental function.

As a result, some neuropsychological conditions, such as Broca’s aphasia (speech deficits), prosopagnosia (a difficulty recognising faces, also known somewhat misleadingly as “face blindness”) and Alien Hand syndrome (a limb seeming to act of its own volition) have become extremely well-known – at least in psychological circles – and extensively studied. However, others are virtually unheard of, even though their importance to our understanding of the brain is significant.

Neuropsychologist Alfredo Ardila at Florida International University has just published in the journal Psychology and Neuroscience an overview of four of these little-known conditions, “so rare that they are not even mentioned in basic neuropsychology textbooks”: Central achromatopsia, Bálint’s syndrome, Pure-word deafness, and aphasia of the supplementary area. This follows a paper he published last year covering four other rare but important neuropsychological syndromes: Somatoparaphrenia, Akinetopsia, Reduplicative Paramnesia, Autotopagnosia.

“In neuropsychology … there are some unusual syndromes that are found very sporadically,” he writes. “But their rarity does not diminish their importance in the fundamental understanding about the brain organisation of cognition, as well as in clinical analysis of patients with brain pathologies.”

Here’s a brief breakdown of what Ardila has to say about these rare conditions and why they’re important.

Continue reading “Eight important neuropsychological syndromes you’ve probably never heard of” →