Brain Damage
External Damage
---Damage to the outside of the cerebral hemisphere can have various results depending on which areas is affected. For example, areas 44 and 45 are the motor speech areas of Broca. Damage results in an inability to produce connected speech sounds. Area 22 is associated with the recognition of sounds and damage to this area results in an inability to recognise familiar sounds or to interpret and understand speech.
---Area 39 is the visual equivalent of area 22. Failure to recognise objects or understand written language results if this area received injury.
---Area 40 is concerned with interpretation. Injury can result in a failure to interpret the nature of an object by touch, or the loss of awareness of bodily parts and spatial relationships.
Internal Damage
The structures inside the brain are extremely complex, so the effects of damage to a particular structure vary considerably depending on exactly which parts have suffered.
A. Optic nerve damage leads to partial or total blindness.
B. Hypothalamus damage can result in a wide range of effects, from inability to regulate appetite and body temperature, to hormonal and emotional disturbances.
C. Hippocampus malfunction interferes with short-term memory.
D. Brainstem damage also results in many different defects including loss of pain and temperature sensation if the medulla is affected and weakness or paralysis of muscles if the pons or medulla suffer.
E. Thalamus malfunction interferes with the transmission of sensations, often resulting in excess sensitivity to pain, heat, and other stimuli.
F. The cerebellum is important in balance and fine control of movement. The more obvious effects of damage are lack of equilibrium resulting in a staggering gait and a tendency to fall over, and reduced muscular co-ordination shown by tremor, slurred speech and disjointed movements.