Luria on temporal cortex

Destruction of temporal cortex does not cause loss of hearing, but does cause loss of differentiation of combinations of sounds (numerous citations, working brain p. 131). This was also true even with very small lesions. Semernitskaya (1945) noted ability to discern simple sounds but not to repeat series of taps or rhythms, nor to identify same.

Luria discusses the "phonemic system" of language (p134) in which some characteristics of sounds are crucial in one language and unimportant in another; in order to distinguish these sounds of speech in any language it is necessary to code them according to the system, pick out the useful characteristics and to separate them from unimportant features known as variants. He cites Trubezkoi and Jakobson as writing laws about the perception of sounds of speech.

Luria equates "acoustic agnosia" and "sensory aphasia" and believes disturbance of audioverbal memory is closely related. Further he describes "increased mutual inhibition" of auditory traces, a characteristic defect of the pathological state in the temporal cortex." Presenting acoustic stimuli at longer intervals decreases inhibition and thereby decreases errors. Cites unpublished work of Tsvetkova, and of Luria, Sokolov and Klimkovsky (1967) (Neuropsychologia).

Luria attributes the naming defect to difficulty with phonemic imprecision the inability "to profit from the prompting at the beginning of the word." Speech disorder (up to "word salad") as due to some words being phonemically defective, others with wrong word choice, with an unawareness of errors and inability to self correct. An inability to write is similarly due to phonemic frustration at finding required sounds and letters. On the other hand, the ability to write a signature, which is really a motor automatism, is a "clear example of a change in structure and cerebral organization of a process in the course of functional development" (Luria et al. , 1970, Neuropsychologia). He notes the ability of some people to copy sentences but not to write to dictation.

Speech hearing deficits do not imply by any stretch deficit in musical hearing.. Luria has a famous case report of a musician who was aphasic but still performed. Similarly, melodic and intonational aspects of speech are not impaired.