10_Language_B55_06

Lecture Objectives

• Scrutinize the relationship between handedness and cerebral dominance for language processing.

• Articulate biological causes and symptoms associated with Broca’s aphasia and apraxia of speech.

• Describe the biological causes and symptoms of Wernicke’s aphasia.

• Explore the Dual Route model of reading and its relevance to VWFA, pure alexia, and developmental dyslexia.

• Illustrate the involvement of the right hemisphere in linguistic processing.

• Synthesize learned materials about reading journal articles for the final examination preparation.

Handedness and Cerebral Dominance

• Wada Test: used to determine hemispheric dominance for language in patients with epilepsy.

• High concordance (90%+) between fMRI and Wada Test findings (Woermann et al., 2003).

• Relationship to Handedness: Considerations for exclusion criteria in neuroimaging studies.

Broca’s Aphasia

• Impaired Speech Production: Case studies underlining symptoms of Broca’s aphasia.

  • Case #1: Louis Victor Leborgne

    • Chronic epilepsy; only one utterance, "tan"; other mental faculties intact.

  • Case #2: Lazare Lelong

    • Treated for dementia; could produce limited distinct utterances.

• Symptoms of Broca’s Aphasia:

  • Impaired fluency: effortful and slow speech, difficulties with prosody.

  • Agrammatism: preference for content words over function words.

  • Paraphasias are frequent; comprehension is largely intact, although complex syntax poses challenges.

Wernicke’s Aphasia

• Fluency vs. Comprehension Distinctions:

  • Fluency Features: Continuous speech flow but content is often incoherent ("word salad").

  • Symptoms: Comprehension impaired, despite intact prosody.

Conduction Aphasia

• Results from damage to the arcuate fasciculus; characterized by difficulties in repeating phrases despite good comprehension.

Dual Route Model of Reading

• Key Research: Analysis of the visual word form area (VWFA) in the left fusiform gyrus (McCandliss et al., 2003).

• Hemianopic Alexia: Condition linked to blindness of half the visual field; can read single words but struggle with longer strings.

• Pure Alexia: Struggles to read even single words regardless of visual field issues.

Developmental Dyslexia

• Defined as a brain-based learning disability affecting word recognition, spelling, and decoding tasks.

Right Hemisphere Involvement in Language

• The right hemisphere's role in pragmatic language use, discourse processing, and interpreting social situations (Parola et al., 2016; St. George et al., 1999).

Skills for Journal Article Reading

1. Abstract Dissection: Identify key components and evaluate relevance.

2. Introduction: Understand research context and hypotheses.

3. Methods: Visualize participant experiences and relate to key results.

4. Results: Properly articulate figures and tables.

5. Discussion: Interpret results, limitations, and future research directions.

Final Examination Preparation

• Focus on essential pieces of information rather than memorization. Expect one new journal article one week prior to the exam.