Transcript PowerPoint Presentation - Right Hemisphere: Role in Recovery

Right Hemisphere: Role in
Recovery
By
Emily Seidman & Peter Peloquin
RH To The RESCUE
RH
LH
Figure 1: Location of the Language
Areas of the Brain
Barlow Case Study
• 1877 Thomas Barlow, London physician, published a
case of “functional speech recovery” following brain
damage.
• The case involved a ten year old boy who had lost his
speech, regained it, and then lost it again.
• Post-mortem studies of brain revealed morphological
changes in brain volume in Broca’s increases in calcified
brain nodules in the left facial motor area
• These morphological changes also were seen in the
right hemisphere.
• Barlow’s case provoked subsequent investigations on
the possible “takeover” functions of the right hemisphere.
New Procedures and Tests
• Only recently has the role of the right hemisphere in language
processing been studied thoroughly (Finger 2003).
• New neurological procedures and scans have enabled
researchers to study speech after unilateral and bilateral brain
lesions.
• One of the first tests, The Wada test, involves injecting a
barbiturate into the carotid artery that leads to one side of the
brain.
• An injection of carotid into the left side of the brain carotid
results in severely impaired speech production in 97% of the
population.
• However, a right-sided carotid injection was found to inhibit
speech in patients with left-hemisphere damage extending
into Broca’s area.
Role of RH
• It has been hypothesized that although the right hemisphere
plays a small role in speech production, the right hemisphere
acquires the ability to regulate speech more effectively when
the language areas of the left-hemisphere are damaged.
• A case of functional recovery: The role of right frontal
activation
• Finger et al. 2003 reported additional evidence for the
increased speech production capabilities of the right
hemisphere after left hemispheric damage. The study
consisted one non-fluent aphasiac, who had most of the
damage in the left frontal cortex near Broca’s area.
• His aphasia was labeled “incomplete” because he continued
to do well on word generation tasks which normally activate
the area he had sustained damage to, the frontal cortex.
Figure 2: A case of functional recovery; The role of right
frontal activation
(a)
(b)
(c)
• Part (a) of represents PET-scans of the coronal sections of a healthy
individual performing a speech production task.
• Part (b) shows a structural MRI of a lesion to the frontal region (Broca’s
Area) of a patient who has suffered a stroke.
• Part (c) shows a PET scan of the same patient during a speech production
task.
• The right frontal activation is prominent in the patient post-stroke.
• Researchers believe that right frontal activation could be one of many
mechanisms accounting for speech recovery.
Conclusions
• In patients with LH lesions, PET-scans revealed
abnormally high activation of the right frontal brain
regions.
• This evidence indicates that the patient’s preserved word
generation abilities may be due to the recruitment of
right-frontal regions.
• Other studies also have shown increased right-frontal
activation during word generation tasks six months to
one year after stroke.
• The right frontal activation is pronounced in the patient
post-stroke. Therefore, researchers believe that right
frontal activation may play a critical role in speech
recovery in patients with LH lesions.
NO Speech & Hearing Center
• Primarily autistic children
• Currently 4000 patients
• Treat patients autism, down syndrome, Broca’s aphasia,
Wernicke’s aphasia, minor and major speech
impediments, pronounciation.
• 8-12 speech therapists