An observational study of cognitive impairment in amyotrophic lateral sclerosis.
BACKGROUND
Cognitive impairment is increasingly recognized in patients with amyotrophic lateral sclerosis (ALS). Clinical and pathologic features overlap in frontotemporal lobar dementia and ALS. Demographics, respiratory status, bulbar site of onset, and disease severity are potential risk factors for cognitive impairment in ALS.


OBJECTIVE
To further delineate the frequency, nature, and implications of cognitive impairment in ALS and to assess previously identified risk factors.


METHODS
Case-control and retrospective cohort study.


METHODS
Academic referral center.


METHODS
Forty consecutive patients with ALS underwent baseline neurologic and neuropsychologic examinations. Cognitive test performance was compared in patients with ALS and matched controls. An exploratory analysis of the relationship between cognitive performance and ALS survival was performed.


METHODS
Neuropsychologic test performance, ALS severity, and survival.


RESULTS
Twelve patients (30%) showed evidence of cognitive impairment, including 9 (23%) who met the neuropsychologic criteria for dementia. No statistically significant differences were found between demented and nondemented ALS groups regarding demographics, family history, site of onset, bulbar dysfunction, or ALS severity. Only 1 patient with dementia had bulbar-onset disease. An association was observed between increasing ALS severity and declining verbal fluency performance. Demented patients with ALS showed predominant impairment in free recall, executive function, and naming, with relative preservation of attention, psychomotor speed, and visuospatial function. No association was observed between cognition and survival, controlling for ALS severity.


CONCLUSIONS
Nearly a third of the patients with ALS showed evidence of cognitive impairment in a pattern consistent with frontotemporal lobar dementia. Cognitive performance was not related to site of onset or survival.
Department of Neurology, Gertrude H. Sergievsky Center, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Eleanor and Lou Gehrig MDA/ALS Research Center, New York, NY, USA.
Gregory A
GA
Rippon
Nikolaos
N
Scarmeas
Paul H
PH
Gordon
Peregrine L
PL
Murphy
Steven M
SM
Albert
Hiroshi
H
Mitsumoto
Karen
K
Marder
Lewis P
LP
Rowland
Yaakov
Y
Stern
D000690:Amyotrophic Lateral Sclerosis / Q000150:complications* / Q000401:mortality; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D003072:Cognition Disorders / Q000209:etiology*; D015331:Cohort Studies; D003710:Demography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D019370:Observation; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012720:Severity of Illness Index; D016019:Survival Analysis