Differential Neuropsychological Profile of Patients With Amyotrophic Lateral Sclerosis With and Without C9orf72 Mutation.

OBJECTIVE: To determine whether the neuropsychological profiles of patients with amyotrophic lateral sclerosis (ALS) with (ALSC9+) and without (ALSC9-) C9orf72 expansion are different, we administered a battery of neuropsychological tests to 741 patients with ALS (68 ALSC9+ and 673 ALSC9-) and 129 controls. METHODS: The study population includes 741 patients with ALS who were consecutively diagnosed at the Turin ALS expert center in the 2010-2018 period and who underwent both cognitive/behavioral and genetic testing. Patients' neuropsychological patterns were compared (1) at the same degree of cognitive and behavioral deficit according to the revised ALS-Frontotemporal Dementia Consensus Criteria and (2) at the same level of motor impairment according to the King staging system. RESULTS: Despite being about 7 years younger, ALSC9+ patients had significantly lower scores in tests exploring executive function and verbal memory both when classified as cognitively normal and when diagnosed in the intermediate cognitive categories. Considering the clinical perspective, ALSC9+ patients showed significantly lower scores compared to ALSC9- patients at King stage 1 and 3 in almost all the examined neuropsychological domains; at King stage 2, ALSC9+ patients were more severely affected only in the verbal memory domain. Behavioral function was comparably impaired in the 2 cohorts. CONCLUSIONS: ALSC9+ patients show a different neuropsychological profile compared to ALSC9- patients, being more impaired in executive functions and verbal memory domains at all King stages. Verbal memory emerged as a particularly vulnerable function in ALSC9+, with worse performances even when patients were still classified as cognitively normal.

Metabolic brain changes across different levels of cognitive impairment in ALS: a 18F-FDG-PET study.

OBJECTIVE: To identify the metabolic changes related to the various levels of cognitive deficits in amyotrophic lateral sclerosis (ALS) using 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG-PET) imaging. METHODS: 274 ALS patients underwent neuropsychological assessment and brain 18F-FDG-PET at diagnosis. According to the criteria published in 2017, cognitive status was classified as ALS with normal cognition (ALS-Cn, n=132), ALS with behavioural impairment (ALS-Bi, n=66), ALS with cognitive impairment (ALS-Ci, n=30), ALS with cognitive and behavioural impairment (ALS-Cbi, n=26), ALS with frontotemporal dementia (ALS-FTD, n=20). We compared each group displaying some degree of cognitive and/or behavioural impairment to ALS-Cn patients, including age at PET, sex and ALS Functional Rating Scale-Revised as covariates. RESULTS: We identified frontal lobe relative hypometabolism in cognitively impaired patients that resulted more extensive and significant across the continuum from ALS-Ci, through ALS-Cbi, to ALS-FTD. ALS-FTD patients also showed cerebellar relative hypermetabolism. ALS-Bi patients did not show any difference compared with ALS-Cn. CONCLUSIONS: These data support the concept that patients with cognitive impairment have a more widespread neurodegenerative process compared with patients with a pure motor disease: the more severe the cognitive impairment, the more diffuse the metabolic changes. Otherwise, metabolic changes related to pure behavioural impairment need further characterisation.

ALS phenotype is influenced by age, sex, and genetics: A population-based study.

OBJECTIVE: To assess the determinants of amyotrophic lateral sclerosis (ALS) phenotypes in a population-based cohort. METHODS: The study population included 2,839 patients with ALS diagnosed in Piemonte, Italy (1995-2015). Patients were classified according to motor (classic, bulbar, flail arm, flail leg, predominantly upper motor neuron [PUMN], respiratory) and cognitive phenotypes (normal, ALS with cognitive impairment [ALSci], ALS with behavioral impairment [ALSbi], ALSci and ALSbi combined [ALScbi], ALS-frontotemporal dementia [FTD]). Binary logistic regression analysis was adjusted for sex, age, and genetics. RESULTS: Bulbar phenotype correlated with older age (p < 0.0001), women were more affected than men at increasing age (p < 0.0001), classic with younger age (p = 0.029), men were more affected than women at increasing age (p < 0.0001), PUMN with younger age (p < 0.0001), flail arm with male sex (p < 0.0001) and younger age (p = 0.04), flail leg with male sex with increasing age (p = 0.008), and respiratory with male sex (p < 0.0001). C9orf72 expansions correlated with bulbar phenotype (p < 0.0001), and were less frequent in PUMN (p = 0.041); SOD1 mutations correlated with flail leg phenotype (p < 0.0001), and were less frequent in bulbar (p < 0.0001). ALS-FTD correlated with C9orf72 (p < 0.0001) and bulbar phenotype (p = 0.008), ALScbi with PUMN (p = 0.014), and ALSci with older age (p = 0.008). CONCLUSIONS: Our data suggest that the spatial-temporal combination of motor and cognitive events leading to the onset and progression of ALS is characterized by a differential susceptibility to the pathologic process of motor and prefrontal cortices and lower motor neurons, and is influenced by age, sex, and gene variants. The identification of those factors that regulate ALS phenotype will allow us to reclassify patients into pathologically homogenous subgroups, responsive to targeted personalized therapies.

Cognitive impairment across ALS clinical stages in a population-based cohort.

OBJECTIVE: To assess the association of the degree of severity of motor impairment to that of cognitive impairment in a large cohort of patients with amyotrophic lateral sclerosis (ALS). METHODS: This is a population-based cross-sectional study on patients with ALS incident in Piemonte, Italy, between 2007 and 2015. Cognitive status was classified according to the revised ALS-FTD Consensus Criteria. The King system and the Milano Torino Staging system (MiToS) were used for defining the severity of motor impairment. RESULTS: Of the 797 patients included in the study, 163 (20.5%) had ALS-frontotemporal dementia (FTD), 38 (4.8%) cognitive and behavioral impairment (ALScbi), 132 (16.6%) cognitive impairment (ALSci), 63 (7.9%) behavioral impairment (ALSbi), 16 (2.0%) nonexecutive impairment, and 385 (48.2%) were cognitively normal. According to King staging, the frequency of cases with ALS-FTD progressively increased from 16.5% in stage 1-44.4% in stage 4; conversely, the frequency of ALSci, ALSbi, and ALScbi increased from King stage 1 to King stage 3 and decreased thereafter. A similar pattern was observed with the MiToS staging. ALS-FTD was more frequent in patients with bulbar involvement at time of cognitive testing. Patients with C9ORF72 expansion (n = 61) showed more severe cognitive impairment with increasing King and MiToS stages. CONCLUSION: Our findings suggest that ALS motor and cognitive components may worsen in parallel, and that cognitive impairment becomes more pronounced when bulbar function is involved. Our data support the hypothesis that ALS pathology disseminates in a regional ordered sequence, through a cortico-efferent spreading model.

Validation of the revised classification of cognitive and behavioural impairment in ALS.

OBJECTIVE: In 2017, the diagnostic criteria for cognitive and behavioural impairment in amyotrophic lateral sclerosis (ALS) with frontotemporal dementia (ALSFTD-1) have been modified (ALSFTD-2) with the inclusion of a novel category (ALS with combined cognitive and behavioural impairment, ALScbi) and with changes of operational criteria of the other categories (ALS with cognitive impairment (ALSci), ALS with behavioural impairment (ALSbi) and ALS with frontotemporal dementia (ALS-FTD)). We compared the two sets of criteria to assess the effect of the revised criteria on the cognitive classification of patients with ALS. METHODS: Two cohorts of patients with ALS were included in this study: a population-based cohort including patients identified through the Piemonte/Valle d'Aosta register for ALS in the 2014-2017 period (n=321), and a referral cohort recruited at the Turin ALS centre and at the ALS centre of the Maugeri Institute in Milan in the same period (n=205). Cognitive function was classified in blind by two neuropsychologists expert in ALS. RESULTS: ALSFTD-2 criteria determined a shift of about 15% of patients from their original category to a new one. In both cohorts, about 9% of patients were reclassified to the novel category ALScbi. Among patients previously classified as cognitively normal, 14 (4.3%, population-based cohort) and 19 (9.3%, referral cohort) were reclassified as ALSbi or ALSci. The median survival of the different categories was significantly different with both with sets of criteria. CONCLUSIONS: The new ALSFTD-2 criteria, compared with the old ones, have positive effects on the clinical practice being more sensitive to the early cognitive impairment and having a better prognostic yield.