Catherine Lynch

The syndrome of cognitive impairment in amyotrophic lateral sclerosis: a population-based study

Background Despite considerable interest, the population-based frequency, clinical characteristics and natural history of cognitive impairment in amyotrophic lateral sclerosis (ALS) are not known. Methodology The authors undertook a prospective population-based study of cognitive function in 160 incident Irish ALS patients and 110 matched controls. Home-based visits were conducted to collect demographic and neuropsychological data. Patients were classified using the recently published consensus criteria and by a domain-based classification of both executive and non-executive cognitive processes. Results 13.8% of patients fulfilled the Neary criteria for frontotemporal dementia. In addition, 34.1% of ALS patients without evidence of dementia fulfilled the recently published consensus criteria for cognitive impairment. Non-demented ALS patients had a significantly higher frequency of impairment in language and memory domains compared to healthy controls. These deficits occurred primarily in patients with executive dysfunction. 14% of ALS patients had evidence of cognitive impairment without executive dysfunction, and no cognitive abnormality was detected in almost half the cohort (46.9%). Conclusion Co-morbid dementia occurs in approximately 14% of patients with a new diagnosis of ALS. Cognitive impairment, predominantly but not exclusively in the form executive dysfunction, is present in more than 40% of ALS patients who have no evidence of dementia. Cognitive impairment in ALS is not a universal feature, and its manifestations may be more heterogeneous than previously recognised.

Cognitive and clinical characteristics of patients with amyotrophic lateral sclerosis carrying a C9orf72 repeat expansion: a population-based cohort study

Summary Background Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease of upper and lower motor neurons, associated with frontotemporal dementia (FTD) in about 14% of incident cases. We assessed the frequency of the recently identified C9orf72 repeat expansion in familial and apparently sporadic cases of ALS and characterised the cognitive and clinical phenotype of patients with this expansion. Methods A population-based register of patients with ALS has been in operation in Ireland since 1995, and an associated DNA bank has been in place since 1999. 435 representative DNA samples from the bank were screened using repeat-primed PCR for the presence of a GGGGCC repeat expansion in C9orf72. We assessed clinical, cognitive, behavioural, MRI, and survival data from 191 (44%) of these patients, who comprised a population-based incident group and had previously participated in a longitudinal study of cognitive and behavioural changes in ALS. Findings Samples from the DNA bank included 49 cases of known familial ALS and 386 apparently sporadic cases. Of these samples, 20 (41%) cases of familial ALS and 19 (5%) cases of apparently sporadic ALS had the C9orf72 repeat expansion. Of the 191 patients for whom phenotype data were available, 21 (11%) had the repeat expansion. Age at disease onset was lower in patients with the repeat expansion (mean 56·3 [SD 8·3] years) than in those without (61·3 [10·6] years; p=0·043). A family history of ALS or FTD was present in 18 (86%) of those with the repeat expansion. Patients with the repeat expansion had significantly more co-morbid FTD than patients without the repeat (50% vs 12%), and a distinct pattern of non-motor cortex changes on high-resolution 3 T magnetic resonance structural neuroimaging. Age-matched univariate analysis showed shorter survival (20 months vs 26 months) in patients with the repeat expansion. Multivariable analysis showed an increased hazard rate of 1·9 (95% 1·1–3·7; p=0·035) in those patients with the repeat expansion compared with patients without the expansion Interpretation Patients with ALS and the C9orf72 repeat expansion seem to present a recognisable phenotype characterised by earlier disease onset, the presence of cognitive and behavioural impairment, specific neuroimaging changes, a family history of neurodegeneration with autosomal dominant inheritance, and reduced survival. Recognition of patients with ALS who carry an expanded repeat is likely to be important in the context of appropriate disease management, stratification in clinical trials, and in recognition of other related phenotypes in family members. Funding Health Seventh Framework Programme, Health Research Board, Research Motor Neuron, Irish Motor Neuron Disease Association, The Motor Neurone Disease Association of Great Britain and Northern Ireland, ALS Association.

Rate of familial amyotrophic lateral sclerosis: a systematic review and meta-analysis

Background The population rate of familial amyotrophic lateral sclerosis (FALS) is frequently reported as 10%. However, a systematic review and meta-analysis of the true population based frequency of FALS has never been performed. Method A Medline literature review identified all original articles reporting a rate of FALS. Studies were grouped according to the type of data presented and examined for sources of case ascertainment. A systematic review and meta-analysis of reported rates of FALS was then conducted to facilitate comparison between studies and calculate a pooled rate of FALS. Results 38 papers reported a rate of FALS. Thirty-three papers were included in analysis and the rate of FALS for all studies was 4.6% (95% CI 3.9% to 5.5%). Restricting the analysis to prospective population based registry data revealed a rate of 5.1% (95% CI 4.1% to 6.1%). The incidence of FALS was lower in southern Europe. There was no correlation between rate of FALS and reported SOD1 mutation rates. Conclusion The rate of FALS among prospective population based registries is 5.1% (CI 4.1 to 6.1%), and not 10% as is often stated. Further detailed prospective population based studies of familial ALS are required to confirm this rate.

Cognitive changes predict functional decline in ALS A population-based longitudinal study

Objective: To determine whether cognitive status in patients with amyotrophic lateral sclerosis (ALS) is a useful predictor of attrition and motor and cognitive decline. Methods: Cognitive testing was undertaken in a large population-based cohort of incident ALS patients using a longitudinal, case-control study design. Normative data for neuropsychological tests were generated using age-, sex-, and education-matched healthy controls who also underwent repeated assessments. Data were analyzed to generate models for progression/spread. Results: One hundred eighty-six patients with ALS who had no evidence of C9orf72 hexanucleotide repeat expansion were enrolled. A second and third assessment were undertaken in 98 and 46 of the patients with ALS, respectively. Executive impairment at the initial visit was associated with significantly higher rates of attrition due to disability or death and faster rates of motor functional decline, particularly decline in bulbar function. Decline in cognitive function was faster in patients who were cognitively impaired at baseline. Normal cognition at baseline was associated with tendency to remain cognitively intact, and with slower motor and cognitive progression. Conclusions: Non-C9orf72–associated ALS is characterized by nonoverlapping cognitive subgroups with different disease trajectories. These findings have important implications for models of ALS pathogenesis, and for future clinical trial design.

Proposed criteria for familial amyotrophic lateral sclerosis

There is currently no consensus on the defi nition of familial ALS (FALS). We propose criteria for FALS that incorporate family history and genetic analysis. The aim is to increase the yield of genes causing FALS and to facilitate comparative interpretation of epidemiological and genetic FALS data. Familial amyotrophic lateral sclerosis (FALS) is clinically indistinguishable from sporadic amyotrophic lateral sclerosis (ALS) and accounts for 5% of reported cases of ALS (1). ALS is generally accepted to be familial if one or more fi rstor second-degree relatives are reported to suffer from the condition (2). However, lack of a clear defi nition leads to diffi culty in interpreting epidemiological and genetic studies. A recent review of all epidemiological studies reporting rates of FALS showed that only 6% (2/33) of studies provided a defi nition for FALS. Similarly, only two of 13 (15%) papers reporting the rate of SOD1 mutations in specifi c cohorts defi ne the term FALS, and the two defi nitions differ (3,4). Accurate reporting of the rate of FALS within a cohort is dependent on the availability of a detailed family history from every patient diagnosed with ALS. A number of factors can confound the ascertainment of familial disease (5) (Table I). It has been recently reported that kindreds comprising only two affected family members account for up to 50% of all FALS cases (2). Using both information for lifetime adjusted individual risk of dying from ALS (1:350 males and 1:472 females) (6,7) and kindred size, it is possible to calculate the probability of a second person within a kindred developing ALS by chance. It is apparent from Figure 1 that two cases of sporadic ALS within a large kindred could account for a sizeable proportion of currently reported FALS kindreds. Kindreds with three or more reported cases of ALS are less likely

Grey matter correlates of clinical variables in amyotrophic lateral sclerosis (ALS): a neuroimaging study of ALS motor phenotype heterogeneity and cortical focality

Background Body region of onset and functional disability are key components of disease heterogeneity in amyotrophic lateral sclerosis (ALS). Objectives To evaluate patterns of grey matter pathology in the motor cortex and correlate focal structural changes with functional disability. Methods We conducted a single-centre neuroimaging study of a cohort of 33 cognitively normal patients with amyotrophic lateral sclerosis (ALS) and 44 healthy controls. A voxel-wise generalised linear model was used to investigate the distribution of disease burden within the motor cortex in relation to clinical disability. Results Patients with bulbar onset have bilateral focal atrophy in the bulbar segment of the motor homunculus compared with patients with limb onset who have focal cortical changes in the limb segment of their motor strip. Furthermore, the extent to which different body regions are affected in ALS corresponds to the extent of focal grey matter loss in the primary motor cortex. Cortical ALS pathology also extends beyond the motor cortex affecting frontal, occipital and temporal regions. Conclusions Focal grey matter atrophy within the motor homunculus corresponds with functional disability in ALS. The findings support the existing concepts of cortical focality and motor phenotype heterogeneity in ALS.

Aggregation of neurologic and neuropsychiatric disease in amyotrophic lateral sclerosis kindreds: A population‐based case–control cohort study of familial and sporadic amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is associated with frontotemporal dementia (FTD) in 14% of cases. Five percent report a family history of ALS, and other ALS patients report a family history of other neurodegenerative diseases. The objective of this study was to conduct a family aggregation study of ALS, and neurodegenerative and neuropsychiatric conditions in ALS kindreds and matched healthy controls. The aim was to determine the true rate of familial ALS and the recurrence risk of ALS in family members, and to identify kindreds with increased aggregation of neurodegenerative and neuropsychiatric disease in the context of the recently described expanded hexanucleotide repeat in C9orf72.

Aggregation of neurologic and neuropsychiatric disease in amyotrophic lateral sclerosis kindreds: A population-based case-control cohort study of familial and sporadic amyotrophic lateral sclerosis: Byrne et al: Familial and Sporadic ALS

Amyotrophic lateral sclerosis (ALS) is associated with frontotemporal dementia (FTD) in 14% of cases. Five percent report a family history of ALS, and other ALS patients report a family history of other neurodegenerative diseases. The objective of this study was to conduct a family aggregation study of ALS, and neurodegenerative and neuropsychiatric conditions in ALS kindreds and matched healthy controls. The aim was to determine the true rate of familial ALS and the recurrence risk of ALS in family members, and to identify kindreds with increased aggregation of neurodegenerative and neuropsychiatric disease in the context of the recently described expanded hexanucleotide repeat in C9orf72.

Aggregation of neurologic and neuropsychiatric disease in amyotrophic lateral sclerosis kindreds

Amyotrophic lateral sclerosis (ALS) is associated with frontotemporal dementia (FTD) in 14% of cases. Five percent report a family history of ALS, and other ALS patients report a family history of other neurodegenerative diseases. The objective of this study was to conduct a family aggregation study of ALS, and neurodegenerative and neuropsychiatric conditions in ALS kindreds and matched healthy controls. The aim was to determine the true rate of familial ALS and the recurrence risk of ALS in family members, and to identify kindreds with increased aggregation of neurodegenerative and neuropsychiatric disease in the context of the recently described expanded hexanucleotide repeat in C9orf72.

The accuracy of death certification for ALS/MND in Ireland

Background: Epidemiological analysis of ALS cases among personnel deployed to the Gulf between 199