The Frontal lobes - Mahidol University

19/07/54
Language Impairment
Broca's area resides in the left frontal
lobe and lesion of this area produces a
well‐known impairment of language
referred to as Broca's aphasia.
Patients with dorsolateral frontal lobe
lesions may also have additional
language impairment that is distinct
from Broca's aphasia.
Language Impairment
The first of these is a general reduction of
language production although language
utterances that are produced are fluent
and maintain correct syntax.
Patients with frontal lobe lesions have
difficulty initiating speech and
maintaining a complex, spontaneous
conversation.
Language Impairment
This is referred to as a deficit in
"verbal fluency", although language
productions are actually fluent.
Language Impairment
Patients with frontal lesions in secondary
motor control areas may also display
mutism.
In particular, lesions of the cingulum often
result in essential mutism.
Here, the patient comprehends language but
cannot produce any vocalizations, including
language.
Language Impairment
This is viewed as a deficit of the basic
motor control of the oral apparatus to
the point where there is no initiation of
activity.
The patient is often indifferent to
communication in general and does
not show the frustration characteristic
of Broca's aphasia.
Language Impairment
A pure agraphia is also associated with
lesions of supplemental motor areas of the
left dorsolateral frontal lobe (Exner's
area).
Exner's area (Broadman area #46
46) is above
Broca's area (Broadman area #44,45) and
anterior to the primary motor control area.
In this disorder, the patient is not aphasic
but has difficulty writing and reading.
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