Classical Clinical Disorders Associated with Prefrontal Damage and Disorders of Higher Cortical Function

Clinical Disorders Associated with Prefrontal Damage

  1. Schizophrenic Thought Disorders

  • Involve Frontal Lobe dysfunction

  1. Cortical Dementias

  1. Impaired working memory

  • associated with lesions of the dorsolateral prefrontal cortex

  1. Soft damage or dysfunction of the Prefrontal Cortex is associated with juvenile delinquency

Disorders of Higher Cortical Function

These disorders are difficult to localize and the terminology is quite complex / confusing

There are 3 common types of disorders: Disorders of Language, Disorders of Recognition and Disorders of Movement

Disorders of Language

The most common disorder of language is Aphasia

Aphasia refers to a disturbance in one or more aspects of language processing or the use of symbols for communication. This is due to damage to certain parts of the brain specialized for language processing.

This disorder most frequently occurs after strokes. But there are other causes such as brain tumours, brain injuries and other neurodegenerative diseases like Alzheimer’s

Individual who have this order will often present additional sensory, motor or cognitive deficits

There are 3 common types of aphasia:

  1. Broca's Aphasia / Non-fluent Aphasia

  • Symptoms include: Awkward articulation or restriction of speech and speech fluency, restricted vocabulary and use of grammar to its simplest forms, and preservation of auditory comprehension

  • Associated with damage to the left posterior portion of frontal lobes such as areas 44 and 45

  • The person is often AWARE of the disorder

  1. Wernicke’s Aphasia / Fluent Aphasia

  • Symptoms include 1 of 3 types of speech: Paraphasia which is the unintended use or combination of words. Logorrhea which is the excessive and incoherent speech. Empty Speech which is fluent speech that lacks meaningful content

  • Associated with lesions in the posterior portion of the left superior temporal lobe / area 22

  • The two most common types of Paraphasia is: Literal Paraphasia and Semantic Paraphasia . Literal Paraphasia involves the substitution of sounds or syllables in words, leading to speech that can be difficult to understand, while Semantic Paraphasia refers to the substitution of words that are related in meaning, often resulting in nonsensical sentences.

  1. Anomic Aphasia

  • Characterized by having difficulty finding words while other aspects of language remains intact

  • Associated with lesions in the left inferior temporal lobe near the temporo-occipital border

Disorders of Recognition

The Most common recognition disorder is Agnosias

Agnosias prevents the recognition of sensory input (objects, faces, sounds) despite intact senses

They are modality specific meaning someone can’t recognize something through one sense (visual) but can recognize the same thing through other senses such as touch or hearing

There are 4 common types of Agnosias:

  1. Gertsmann Syndrome

  • Associated with a cluster of symptoms including finger agnosia, agraphia, acalculia and left-right confusion

  • Associated with damage to the angular gyrus and supramarginal gyrus in the left parietal lobe

  1. Prosopagnosia / face Blindness

  • Involves deficits in the ability to recognize faces,

  • Associated with Damage to the Fusiform gyrus in the inferior temporal lobe in the right hemisphere

  1. Pure Word Deafness

  • Involves the inability to comprehend spoken languages despite intact abilities to read, write and speak,

  • Associated with bilateral damage to the superior temporal gyrus and area 22

  1. Cortical Astereognosis / Tactile Agnosia

  • Involves the inability to recognize an object by touch alone while retaining the ability to identify it visually

  • Associated with damage to the right superior parietal lobule

Disorders of Movement

There is one common disorder: Apraxia

Apraxia involves disorders of skilled movements without evidence of tremor, muscle weakness or sensory dysfunction

Lesions typically involve the corpus callosum and the left supramarginal gyrus