Anatomy of the Brain

Kim Peek’s brain differs from that of the average person. He was born with:-

Macrocephaly

This is when the circumference of a person’s head is larger than average in comparison to the person’s age and sex.

Damage to the Cerebellum

The cerebellum is the region of the human brain that has been implicated in motor control and sensory perception.

Sensory perception involves acquiring, interpreting, selecting, and organizing information derived from our five senses (sight, sound, taste, touch and smell). Despite the damage to his cerebellum, Kim Peek possesses no difficulties in perceiving sensory information.

Kim does, however, face problems with his motor skills. He cannot button up his shirt, nor can he brush his teeth without help. When he first started to walk (at the developmentally delayed age of 4), he did so in a sidelong manner. Until this day, he needs help from his father (and caretaker) Fran to complete every day self-care tasks.

Encephalocele of the Brain

This is a congenital condition (birth defect) where infants have an excess portion or gap in the brain where there is a protruding sac. The sac can be big or small, located on any part of the skull. It may contain portions of disorganized cerebral matter, or excess spinal fluid.

The prognosis/outcome for patients with encephalocele of the brain range from mild to severe, depending on the size and location of the sac.

Kim Peek’s condition has been grossly been defined as ‘a water blister in the back of his brain’. This defect may contribute to some of his difficulties in completing everyday tasks. This can also explain some of the signs of mental retardation and other developmental delays he displayed as a child.

Agenesis of the Corpus Callosum

The corpus callosum is often referred to as the ‘bridge’ between the two hemispheres of the brain. Simply put, it is a bundle of nerves that connects the left side of the brain to the right, and helps with inter-hemispheric communication.

Agenesis of the corpus callosum is also a rare congenital disorder (birth defect) where there is a partial or complete absence of the corpus callosum. This condition has a myriad of manifestations, including problems with perception, speech and language delays, social difficulties, and even mental retardation.

In the case of Kim Peek, doctors and neurologists have speculated that it is this factor that makes him special – his neurons have somehow made other connections in the absence of the corpus callosum, resulting in a complete bypass of that connective ‘bridge’, leading to increased ‘data storage’ section of the brain with enhanced memory capacity.