APHASIA 219 



blast, transfixed the left frontal lobe. The patient recovered 

 and lived for nearly thirteen years, suffering no sensory or motor t 

 deficiency except occasional epileptic convulsions. His intel- 

 lect was impaired; though previously a capable and decent 

 workman, he became vacillating and inefficient in his work and 

 profane in his language. 



Aphasia. One of the most fertile and suggestive fields in 

 the study of associative mechanisms of the brain is to be found 

 in the pathological condition of aphasia. In aphasia the power 

 of intelligent communication by spoken or written language is 

 lost. When this is due to an inability to interpret the meaning 

 of the auditory and visual symbols by which ideas are conveyed, 

 it is known as sensory aphasia or amnesia; when, on the other 

 hand, it is due to an inability to clothe ideas in words, although 

 the words may be present in the patient's consciousness, then 

 the condition is one of motor- aphasia. Motor aphasia may be 

 divided into two varieties subcortical and cortical aphasia. 

 In the subcortical type the patient understands speech and 

 writing perfectly and is able to write normally, but he cannot 

 speak spontaneously or read aloud or repeat words when re- 

 quested to do so. He can conceive words, but cannot express 

 them. When, on the other hand, there is inability to conceive 

 words, a lack of inner word-building power, then the case is 

 one of cortical aphasia. 



The gradations in the loss of the expressive factor may be 

 very minute. A patient may sing a song, yet be unable to speak 

 or write it. In a case described by Broca, the patient retained 

 the power of using the word " three " only, and was obliged to 

 make it do duty for all numerical concepts. Sometimes he 

 can express his ideas in speech, but not in writing (agraphia). 

 Motor aphasia is generally accompanied by paralysis, often 

 transient on the right side, particularly the right arm. This 

 is explained by the proximity of the inferior frontal convolution 

 (Broca's speech area) to the motor area of the arm, and their 

 common blood supply. The speech centre in right-handed 

 persons is situated on the left side of the brain, and in the right 

 side of the brain in left-handed individuals. This is a matter 

 of education. It is no doubt true that after complete destruc- 

 tion of the left inferior frontal convolution the power of speech 



