Right Hemisphere: Role in Recovery

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Right Hemisphere Role in Recovery

• By
• Emily Seidman Peter Peloquin

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RH To The RESCUE
RH
LH
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Figure 1 Location of the Language Areas of the
Brain
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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 Brocas
  increases in calcified brain nodules in the left
  facial motor area
• These morphological changes also were seen in the
  right hemisphere.
• Barlows case provoked subsequent investigations
  on the possible takeover functions of the right
  hemisphere.

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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 Brocas
  area.

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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 Brocas 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.

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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 (Brocas
• 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.

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Conclusions

• In patients with LH lesions, PET-scans revealed
  abnormally high activation of the right frontal
  brain regions.
• This evidence indicates that the patients
  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.

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NO Speech Hearing Center

• Primarily autistic children
• Currently 4000 patients
• Treat patients autism, down syndrome, Brocas
  aphasia, Wernickes aphasia, minor and major
  speech impediments, pronounciation.
• 8-12 speech therapists