Question

Describe the most important deficits related to temporal lobe injury. Explain in detail and give examples.

Answer 1

Temporal lobe is the one of the four major lobes of cerebral cortex in the brain of mammals. It helps to involved in processing sensory input into derived meaning for the appropriate retention of visual memory, language comprehension and emotional changes. Damage of temporal lobes cause difficulty placing words or pictures in to categories.

There are 8 principle symptoms for the temporal lobe injury

• Disturbance of auditory sensation and perception
• Disturbance of selective attention of auditory and visual input.
• Disorders of visual perception.
• Impaired organization and categorisation of verbal material.
• Disturbance of language comprehension.
• Impaired long term Memory.
• Altered personality and affective behavior.
• Altered sexual behavior.

Here we can explain each one with example :

*Disturbance of auditory sensation and perception .

• Here we can see that lesion of the of the left superior temporal gyrus produce problems of speech perception with difficulty in discriminating speech and the temporal order of sounds impaired.
• Lesions of the right superior temporal gyrus produce prosody. Prosody is the study of the metre of verse. Here it means the rhythm of speech.

Lesions of the right superior temporal gyrus can produce disorders of perception of music with inability to discriminate melodies.

* Disturbance of selective attention of auditory and visual input.

• There may be disturbance of visual and auditory input selection. This presents as impairment of short-term memory (also called working memory) and of judgement about the recency of event.
• There may be difficulty using contextual information, in extracting information from the environment and using visual and social cues.

* Disturbance of visual perception.

The inferior temporal cortex is responsible for visual perception and lesions produce inability to recognise faces.

* Impaired organisation and categorisation of verbal material.

The area is responsible for the organisation and categorisation of words and pictures. Impairment of this ability to categorise means reduction in both ability and fluency in listing categories.

*Disturbance of language comprehension

Difficulty to understand the normal spoken languages. So that listeners are aware of over all meaning of speakers utterance.

* Impaired long term memory.

The medial and inferior temporal cortex and hippocampus are responsible for memory.There is complete anterograde amnesia following bilateral removal of medial temporal lobes, including hippocampus and amygdala. There is difficulty recalling information. The left side is responsible for verbal material and the right for non-verbal memory such as faces, tunes and drawings. The difference between retrograde and anterograde amnesia is that retrograde amnesia is loss of memory from before an event. It often happens with head injury with loss of memory leading up to that event, although this is commonly gradually recovered. Anterograde amnesia is loss of memory between the event and the present time.

* Altered personality and affective behaviour

• There is a temporal lobe personality, which may display:
  • An emphasis on trivia and the small details of daily life.
  • Egocentricity that mean selfish.being a selfish one.
  • Pedantic speech this means showing the boring speech or language.
  • Religious preoccupations.
  • A tendency to aggressive outbursts, especially after right temporal lobectomy.
• As well as behavioural change, temporal lobe lesions can present with visual field defects in the form of superior quadrant loss, sometimes called the 'pie in the sky defect

* Alterd sexual behavior.

Temporal lobe lesions may be associated with true hypersexuality, and transvestite and transsexual behaviour. A CVE normally reduces libido but temporal lobe lesions can increase it.Lesions of the medial temporal lobe have been reported to produce hyperphagia, hypersexuality, hyperorality, visual agnosia .