[Language disorders in ALS/FTLD].

Area of Science:

• Neurology
• Neuroscience
• Pathology

Context:

• Frontotemporal lobar degeneration (FTLD) is a clinicopathological entity primarily affecting the frontotemporal lobes.
• Recent research suggests a pathological link between FTLD and Amyotrophic Lateral Sclerosis (ALS).
• FTLD encompasses frontotemporal dementia (FTD), behavioral changes, and language disorders like progressive non-fluent aphasia (PNFA) and semantic dementia (SD).

Purpose:

• To investigate the historical and contemporary understanding of language impairments in ALS.
• To analyze specific writing errors in ALS patients, including kana and kanji character difficulties.
• To explore the relationship between frontotemporal lobe involvement and distinct linguistic deficits in ALS.

Summary:

• An 1893 Japanese case report described aphasia in bulbar-onset ALS, indicating historical recognition of language issues.
• ALS patients exhibit frequent kana letter omissions, paragraphia, and syntactic writing errors, varying individually.
• A double dissociation was observed in kana and kanji writing errors, linked to frontal and temporal lobe involvement, respectively.
• Writing impairments, such as agraphia, can manifest in ALS patients even without overt aphasia.

Impact:

• This research underscores that language problems in ALS may have been historically underestimated.
• Identifies specific writing deficits in ALS that correlate with distinct patterns of frontotemporal lobe degeneration.
• Contributes to a more nuanced understanding of the clinical and pathological spectrum of FTLD and its overlap with ALS.