Chapter

Language profiles in amyotrophic lateral sclerosis

J.B. Orange and A.E. Hillis

in Amyotrophic Lateral Sclerosis and the Frontotemporal Dementias

Published on behalf of Oxford University Press

Published in print October 2012 | ISBN: 9780199590674
Published online November 2012 | e-ISBN: 9780191753466 | DOI: http://dx.doi.org/10.1093/med/9780199590674.003.0005
Language profiles in amyotrophic lateral sclerosis

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Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder linked to cell death of lower motor neurones of the brainstem and spinal cord, and of upper motor neurones of the cerebral cortex. It is the third most common adult-onset neurodegenerative disease. ALS was considered to be restricted largely to motor neurones while cognition was thought to be intact. More recently, however, ALS has been recognized as a multisystem disorder. Cognitive impairment (CI) (35–55%) but not dementia has been demonstrated in a substantial proportion of individuals with ALS who also show deficits on tests of executive function. Typical CIs include disruptions to attention systems and processes, to executive functions, to multiple memory systems, and to visuospatial skills. In particular, studies revealed deficits in verbal and non-verbal fluency tasks, working memory, cognitive flexibility, and sustained attention. Deficits also are found in recognition memory for words and faces, visual perception, reasoning, word generation, word fluency, and executive functions such as planning, organizing, and self-monitoring. Greater detail of the cognitive profiles of persons with ALS is found in associated chapters in this volume.

The language and behavioural disorders associated with ALS discussed in this chapter will be presented as a spectrum of overlapping clinical syndromes, under the umbrella term ‘frontotemporal disease’. Although the former umbrella term was frontotemporal lobar degeneration, this term is now used predominantly to refer to histopathologically confirmed pathology. That is, FTLD is the neuropathological correlate of the majority of individuals with frontotemporal dementia (FTD). The specific association between ALS and frontal lobe impairment has been postulated with symptoms, including emotional changes, memory, language, and general intellectual problems, prominent bulbar features, and bilateral frontal and/or temporal lobar atrophy.

The clinical syndromes of FTD will be referred to in this chapter as behavioural variant frontotemporal dementia (bvFTD), and three variants of primary progressive aphasia (PPA). The focus of the language components in ALS in this chapter will, of course, be on PPA, because the chapter is about language and communication behaviours in ALS. However, the language of individuals with bvFTD is not unaffected, so it will be covered briefly as well. We will first describe the language profiles of the variants of PPA, recognizing that they all overlap, both clinically and pathologically. Individuals with ALS can display symptoms and signs of each of the PPA variants over time. Any of the variants can be and are associated with ALS, although the bvFTD and non-fluent/agrammatic variant of PPA (nfvPPA) are the most commonly associated with clinical ALS, perhaps because they are localized to the frontal lobes (predominantly the left posterior fronto-insular regions in nfvPPA), near the motor strip. The key question of whether individuals with ALS develop neuropsychological evidence of FTD before or after progression of the disease is still unclear. ALS with frontotemporal dementia (ALS/FTD) is estimated to occur in 3% of sporadic cases and 15% of the familial type. The 5–15% of individuals with ALS and dementia generally evolve to the ALS/bvFTD. The nfvPPA is sometimes the primary clinical diagnoses in individuals who eventually develop ALS/FTD.

Chapter.  7046 words. 

Subjects: Neurology

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