Aphasias

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Aphasias
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Aphasia

• Aphasia a disorder of language, including a
  defect or loss of expressive (production) or
  receptive (comprehension) aspects of written or
  spoken language as a result of brain damage.
  (Harley, 2001)
• Affects more than 1 million Americans, with
  80,000 new cases acquired each year

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3 main types of aphasia

• Brocas aphasia
• agrammatic, non-fluent
• Wernickes aphasia
• anomic, fluent (usually retrieve real words that
  are semantically empty. Patients are generally
  unaware that theyre ill)
• Conduction aphasia
• cant repeat what they hear
• Dementia (not aphasia, but still affects
  language) usually fluent and grammatical, just
  nonsensical

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Tests for Aphasia

• From the Boston Diagnostic Aphasia Test
• Patients are shown pictures and asked to describe
  them
• Both of these samples show non-fluent, agrammatic
  aphasics

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Paul Broca founding father of physical
anthropology

• French surgeon who was intrigued with brain size
  and its relationship to age, sex, intelligence,
  race, and environment
• Belonged to an anthropological society whose
  members examined human skulls and conducted
  research on the brains of deceased medical
  patients

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Tan

• Admitted to nursing home at 31 years old, since
  he couldnt speak
• Had been in a nursing home for 21 years when
  Broca was introduced to him
• Seemed to comprehend speech, but could only
  respond with gestures and the syllable tan
• (although able to swear when provoked!)
• When Tan died, Broca performed an autopsy and
  found a frontal lobe lesion in the 3rd frontal
  gyrus of the left hemisphere (Brocas area)

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Comparison of speech from aphasics

• Brocas aphasia YesahMondayerDad and Peter
  H(his own name)and Daderhospitaland
  ahWednesdayWednesday, nine oclock. Ah
  doctorstwoan doctorsand erteethyah.
• (explaining that he came to the hospital for
  dental surgery)

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Non-fluent aphasia

• Disruption in grammatical processes in general.
  Comprehension problems detectable when context
  cant provide correct syntactic interpretation
• Speech is almost entirely nouns and fillers. Very
  few verbs, and fewer inflectional affixes (-s,
  -ed, )
• Caused by damage to Brocas area or Parkinsons
  disease (damages basal ganglia, complex neural
  centers buried inside frontal lobes)

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Wernickes Aphasia

• Fluent, nonsensical speech
• Severe comprehension problems
• Grammar is (mostly) intact
• Most patients are unaware of their language
  problems (agnosia)

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Comparison of speech from aphasics

• Wernickes aphasia Well, this ismother is away
  here working her work out here to get her better,
  but when shes looking, the two boys looking in
  the other part. One their small tile into her
  time here. Shes working another time because
  shes getting, too
• (describing scene of children stealing cookies
  while mothers back is turned)

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Anomia

• Inability to retrieve names (nouns) , caused by
  damage to the angular gyrus (slightly behind
  Wernickes area)
• HW suffered a stroke, highly intelligent but
  could not retrieve nouns from mental dictionary.
  First of all this is falling down, just about,
  and is gonna fall down and theyre both getting
  something to eatbut the trouble is this is gonna
  let go and theyre both gonna fall down
• Often name related objects or distort sounds of
  correct words (phonolgical/semantic neighbors)
• table chair, elbow knee, clip plick, butter
  tubber, ceiling leasing, ankle ankley, no
  mankle, no kankle, comb close, saw it, cit it,
  cut, the comb, the came

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Pure Word Deafness

• Can read, speak, recognize non-linguistic sounds
  (music, slamming doors, animal cries)
• Cannot recognize spoken words, repeat back speech
• Hearing is otherwise normal
• Impaired in phoneme recognition/differentiation
  (/pa/ from /ba/, /ga/ from /ka/ - so no
  categorical perception)
• patients report that they are hearing what youre
  saying, but that it just doesnt compute
• damage to auditory nerve, corpus collosum

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Anomia and Herpes Simplex Encephalitis

• Patients could name nonliving things but not
  living things. HSE caused impaired visual object
  recognition and also impairment at naming or
  describing visual objects (Sartori and Job, 1988,
  Silvery and Gainotti, 1988, Warrington and
  Shallice, 1984)
• Some relevant symptoms of HSE
• Psychiatric symptoms (71)
• Seizures (67)
• Focal weakness (33)
• Memory loss (24)
• Other findings include the following
• Altered mental status
• Photophobia
• Movement disorders
• So There DOES seem to be a connection between
  specific anomias and the kind of general brain
  damage that a patient is suffering (from
  www.emedicine.com)

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Aphasics and swearing

• Most aphasics can swear!
• No syntax required
• Since this is emotional vocabulary, likely stored
  in the right brain
• Connections with subcortical brain structures
  which mediate arousal (including
  amygdala-mediated learning)

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Loss of language vs. loss of intelligence

• Can you still perform higher-level cognitive
  functions if language abilities are damaged? A
  few case studies
• Patient with semantic dementia (damage to
  temporal lobe) couldnt remember what to buy in
  grocery store, but she figured out that, if she
  took used boxes, empty containers, she could
  match those up with what she needed to buy and
  cope with her difficulties
• Catholic monk, Brother John had paroxysmal
  aphasia (due to epilepsy). During spells, he
  would become globally aphasic. Lecours and
  Joanette (1980) recounted a spell in which he was
  taking a train trip from Italy to Switzerland.
  Despite his loss of speech production,
  comprehension, and reading, Brother John was able
  to get off the train at the appropriate spot,
  find his hotel, find another hotel when the first
  one was full, order supper in a restaurant, and
  wait until his language skills returned

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Other language impairments

• Consonants vs. Vowels
• Two Italian patients AS produced errors on
  vowels, but IFA produced errors on consonants
• Complaints of the elderly
• Older adults most frequent complaint is that
  they cant find words. They make pauses, do
  circumlocution, empty speech where pronouns
  dont have a clear referent, make substitution
  errors. Proper nouns are more difficult to
  retrieve than common nouns

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Language and emotion alexithymia depression

• alexithymia difficulty identifying and
  describing emotional states. Lack of
  emotional-expressive words in speech production,
  probably due to lack of right-hemisphere
  information available to speaking
• the right hemisphere organizes lexicon according
  to contextual, affective, idiosyncratic, or
  personalized principles. It has been proposed
  that an affect lexicon (emotional lexicon) is a
  resident of the right hemisphere. (Bowers et al,
  1993)
• Measurably present in patients with bulimia
  nervosa (de Groot, Rodin, Olmstead, 1995)
• Depression affects the rate of speech. It is
  generally hypophonic (not much intonation) and
  slower. Increased pauses, decreases in volume at
  the end of sentences
• patients with depression perform differently on
  acoustic-perceptual tests