Most Aphasias Are Easily, Although Imprecisely, Diagnosed And Localized

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Most Aphasias Are Easily, Although Imprecisely,
Diagnosed And Localized
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• There are eight principle forms of aphasia, which
  result from cortical lesions.
• Four of these forms- Brocas aphasia, mixed
  transcortical, transcortical motor and global
  aphasia- have non-fluent spontaneous speech.
• The remaining four- Wernickes aphasia,
  conduction, transcortical sensory and anomic
  aphasia- have fluent speech.
• Two-thirds of patients with aphasia can be
  classified into one of these forms. The
  remaining cases are mixed forms or subcortical
  aphasias.

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• Aphasia screening requires testing of the
  patients spontaneous speech, comprehension of
  spoken language, repetition of speech,
  confrontational naming ability, reading and
  writing.
• Language assessment begins by listening to
  spontaneous speech. Two critical questions can
  usually be answered while the patient gives the
  chief complaint
• Does the patient speak spontaneously?
• Is speech fluent?

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• It is critical to hear the patient speak in
  sentences, so ask open-ended questions such as
  Why have you come to the hospital?, What is
  your typical weekday like? Some patients
  conceal major language disorders with yes and
  no answers.
• Verbal fluency is the ability to produce flowing,
  smooth speech without word-finding pauses.
  Non-fluent speech is slow, with a rate that is
  usually less than 40 words per minute, sparse, or
  often consisting of single words, effortful,
  dysarthric, dysprosodic and agrammatical.

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• Spontaneous speech should also be assessed for
  articulation, prosody and paraphasias. Prosody
  refers to the distribution of stress and melody
  of speech, and includes both affective and
  non-affective components. Prosody is the chief
  affective component of speech and introduces
  subtle shades of meaning or completely changes
  the impact of a statement. Affective prosody is
  the emotional tone that flavors our speech and
  allows our children and pets to understand what
  we are saying even though they cannot comprehend
  words. Non-affective prosody is the alteration in
  pitch and stress that conveys different messages
  with the same words.

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• Anterior right hemisphere lesions (analog of
  Brocas area) impair spontaneous prosody, causing
  monotonous speech that lacks emotion and
  intonation, while posterior right hemisphere
  lesions (analog of Wernickes area) impair
  comprehension of prosody, leaving patients unable
  to distinguish subtle shades of meaning in
  others speech.
• Paraphasias are syllable or word-substitution
  errors and are most common in fluent aphasia.

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• Comprehension is assessed after spontaneous
  speech. If the patient constructs
  well-formulated answers to questions,
  comprehension is usually normal.
• Repetition is tested by asking the patient to
  repeat words, phrases and sentences. There are
  no ifs, ands, or buts about it or The phantom
  soared across the foggy heath. Listen carefully
  for omissions (e.g. plural endings), additions,
  perseverations or repetitions, paraphasias and
  grammatical errors.
• Confrontational naming is tested by pointing to
  objects and asking the patient to name them.

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• Dysarthria, in its strictest sense, refers to
  abnormal articulation. Dysarthria is common in
  anterior non-fluent aphasia, such as Brocas
  aphasia, and rare in posterior fluent aphasia,
  such as Wernickes aphasia.
• Paretic (flaccid) dysarthria results from
  weakness of articulatory muscles. The voice is
  typically soft or barely audible, low-pitched and
  nasal.

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• Spastic (hypertonic, pseudobulbar) dysarthria
  results from upper motor neuron (corticobulbar)
  lesions, usually due to multiple, bilateral small
  lacunar infarcts. Speech is slow, strained,
  thick and monopitched. Articulation is
  imprecise, especially for consonants, and volume
  may be explosive.
• Ataxic (cerebellar) dysarthria results from
  lesions of the cerebellum or its connections, and
  it is most common in patients with cerebellar
  degeneration and multiple sclerosis. The slurred
  speech is dysarticulated into jerky, irregular
  components. Speech rhythm, volume and pitch are
  variable, and speech may be explosive with poorly
  regulated expiration.

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• Palilalia is involuntary repetition of words,
  phrases and less often, syllables. In most
  patients, speech rate increases and volume
  decreases with repetition.
• Echolalia is the parrot-like repetition of words
  and phrases heard from others.

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Brocas aphasia consists of non-fluent, effortful
speech with relatively preserved comprehension
following left frontal lesions
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• Mutism may occur at the onset of the aphasia, or
  patients may produce only single syllables or
  words. Speech is aspontaneous, sparse and slow
  its rate is fewer than a dozen words per minute.
  Verbal output is agrammatic, even telegraphic,
  because patients utter substantive nouns and
  verbs that carry sentence meaning but omit
  grammatical connecting words, including
  prepositions, articles, conjunctions and adverbs.
  An example is gostoreme, for Do you want to
  go to the store with me?. The writing of
  patients with Brocas aphasia also contains
  grammatical errors.

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• The tip-of-the-tongue phenomenon, in which
  patients utter the initial letter or syllable of
  a word but cannot complete it, is common in
  Brocas aphasia. Also, confrontational naming is
  usually impaired.
• Other clinical features of Brocas aphasia
  include severe disruption of articulation and
  prosody (melody and inflection), impairment of
  repetition that is less severe than impairment of
  spontaneous speech, and frequent phonemic
  paraphasias, which consist of sound or syllable
  substitutions.

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Prosody is the variation in speech rhythm, pitch,
melody, and distribution of stress. Prosody is
the aspect of speech that conveys shades of
meaning through variations in stress and pitch,
independent of words (semantics) and organization
(grammar). Ross and Mesulam (1979) reported two
patients with right frontoparietal strokes who
were unable to express emotional color in their
speech and gestures.
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Wernickes aphasia is often misdiagnosed as a
psychiatric disorder
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• Wernickes aphasia is the antithesis of Brocas
  aphasia. Patients with Wernickes aphasia are
  fluent with normal prosody, often speak
  excessively (logorrhea, verborrhea), create
  paraphasias and neologisms, and have impaired
  comprehension.
• Fluent aphasia can usually be distinguished from
  psychiatric disorders on historical grounds. The
  behavioral change usually develops suddenly
  without prior personality or mood disorders
  precipitating events, such as death of a spouse,
  are absent and patients are usually old.

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• Several features distinguish the speech of
  patients with loose schizophrenia (word
  salad) and Wernickes (or conduction) aphasia.
  Responses to open-ended questions are shorter in
  aphasia paraphasias are common in aphasia and
  rare in schizophrenia vague responses occur in
  both disorders, but are due to word-finding
  problems in aphasia and to circumstantiality in
  psychosis and bizarre and delusional themes
  occur in psychosis.

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• Language disorder in Wernickes aphasia is always
  present but varies among patients. Acutely,
  patients may be mute before the characteristic
  fluent, overflowing speech filled with empty
  phrases, circumlocutions and paraphasias.
  Indeed, a foreigner with Wernickes aphasia
  speaking an unknown language would send almost
  identical to one with normal speech. Describing
  an object or event in an indirect fashion
  paraphasias and the lack of meaningful
  substantive words, such as nouns and verbs, are
  most apparent in spontaneous speech.

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• Paraphasias are usually verbal rather than
  literal that is, they are more likely to consist
  of word substitutions than substitutions of
  phonemes or sounds. Jargon speech contains
  abundant neologisms, or new words, such as
  thintoke. Children with Wernickes aphasia
  tend to speak less fluently than adults, but
  recover more fully.

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• Verbal comprehension deficit is the central
  linguistic component of Wernickes aphasia. The
  best test of comprehension is a series of
  nonsense questions asked in a serious,
  inquisitive manner. Simple questions, such as
  Do two pounds of flour weigh more than one? and
  Are you lying in bed?, can also reveal
  prominent impairment of comprehension.
• Auditory and reading comprehension are usually
  impaired to a similar degree.

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• Patients with Wernickes aphasia also have
  impaired naming and repetition. Writing is
  legible but incomprehensible, with the same
  emptiness, circumlocution and paraphasic errors
  that contaminate speech.
• Patients with Wernickes aphasia usually recover
  some auditory comprehension, although a favorable
  prognosis is less likely than in Brocas aphasia.

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Mutism often occurs in non-aphasic disorders
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• Initially, patients with Brocas or global
  aphasia may be unable to even attempt speaking.
  Associated symptoms usually include right facial
  weakness or hemisensory loss and hemianopsia in
  global aphasia. As mute aphasic patients
  recover, aspontaneous and non-fluent speech
  emerges. Aphasic patients with mutism make
  linguistic writing errors. These include word
  substitutions or paralexias, such as pair
  instead of chair telegraphic writing in which
  connecting grammatical words are deleted, such
  as, I store rice for I want to go to the store
  to buy rice and non-sensical fluent writing, as
  in, The only thing that I wish well you must
  know that the other thing yes that thing of
  course. These errors help distinguish such
  patients from those with non-aphasic mutism.

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• In aphemia muteness often precedes a
  characteristic pattern of slow, hypophonic and
  dysarthric speech
• Lesions in the supplementary motor area (SMA) of
  the dominant hemisphere can cause muteness during
  the first several weeks. Recovery of spontaneous
  speech and repetition follows, but an impairment
  of writing persists.
• Abulia may cause mutism. It is a general
  behavioral slowing and lowered activity which
  results from a variety of pathological processes.
  Abulic patients show little spontaneous motor or
  speech activity and may intermittently fail to
  respond to questions or commands for minutes.
  When responses do occur, they are slow and
  apathetic.

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• Akinetic mutism represents the most intense form
  of abulia as a condition in which the patient
  appears awake and may follow the examiner with
  his eyes but lacks spontaneous motor and verbal
  responses. In addition, he is doubly incontinent
  and responds incompletely to noxious stimuli.
  Akinetic mutism is also known as locked in
  syndrome

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• The locked-in syndrome results from
  de-efferentation of central motor fibers
  supplying facial and body musculature. Lesions
  are located usually in the ventral pons or
  occasionally in the ventral midbrain.
  Pathological processes include infarction,
  hemorrhage, central pontine myelinolysis, tumor
  and encephalitis. Patients are fully alert and
  conscious but can only communicate by blinking or
  moving the eyes. The EEG reveals normal or
  mildly slowed background activity. Any patient
  who is mute should be asked to blink or move the
  eyes on command otherwise, this diagnosis may be
  missed.

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Locked In Syndrome

• Mute and paralyzed but for eye movements.
• Normal cognitive and affective ability
• Can understand people reading and talking to them
• Eye blinking in Morse code can be used to
  communicate
• The cerebral cortex is intact and functioning,
  just disconnected

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• Patients with the chronic vegetative state emerge
  from coma and resume relatively normal sleep-wake
  cycles in which the eyes open during
  wakefulness, but intellectual activity is
  minimal or absent. Unlike patients with
  locked-in syndrome, those in the chronic
  vegetative state do not produce any clear-cut,
  high-level response to verbal stimuli. This
  disorder usually follows severe, diffuse brain
  insults such as hypoxia, ischemia, hypoglycemia
  or head trauma. The EEG usually reveals
  background slowing with decreased voltage. The
  prognosis for a meaningful recovery is dismal.

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Persistent Vegetative State

• Mute, paralyzed, with spontaneous random eye
  movements and reflexive eye blinks.
• A decorticate fetal posture is typically held
• Unaware of surroundings, unresponsive to visitors
  or examiners, some degree of response to very
  basic stimuli such as painful stimuli, strong
  smells, considered devoid of cognitive activity.
• Show waking and sleeping cycles.

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Persistent Vegetative State

• Cerebral cortex and underlying cerebral tissue
  has been destroyed, brain stem structures are
  functioning independently.
• Vegetative functions such as breathing and
  swallowing operate reflexively.
• If a person has been in this state for a month or
  more, little chance of recovery but they live for
  years
• Coma patients may progress to this state

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Coma

• A sustained loss of the capacity for arousal,
  preventing any expression of any potential
  cognitive functions.
• Eyes are closed, sleep wake cycles disappear and
  even extreme stimulation produces no sign of
  response
• Some coma patients do recover and relate that
  they were in a dream sleep like state from which
  they could not awaken and only limited awareness
  of the external environment. The length of the
  coma is the best predictor of recovery

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Glasgow Coma Scale

• Eyes Score
• Open Spontaneously 4
• To Verbal Command 3
• To Pain 2
• No Response 1

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GCS

• Best Motor Response Score
• To Verbal Command, Obeys 6
• To Painful Stimulus,
• Localizes Pain 5
• Flexion-Withdrawal 4
• Flexion-Abnormal 3
• Extension 2
• No Response 1

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GCS

• Best Verbal Response Score
• Oriented and Converses 5
• Disoriented and Converses 4
• Inappropriate words 3
• Incomprehensible sounds 2
• No Response 1
• GCS Total Score 3-15