Widespread cerebral haemodynamics disturbances occur early in amyotrophic lateral sclerosis.

We wished to longitudinally assess early changes in cerebral perfusion (CP) and its relationship to cognitive impairment (CI) in ALS. Fourteen ALS patients at time of diagnosis and 11 spousal controls, both without CI, were longitudinally assessed to determine a relationship between CP and incidence of CI in early stage disease. Neuropsychological testing and CP measurements were performed in both ALS and control groups at the initial assessment (T0) and two time-periods post initial assessment, T1 and T2, taken on average 6.1 and 17.0 months after initial assessment (T0), respectively. CT perfusion was used to measure cerebral blood flow, blood volume, and mean transit time (MTT) for all cortical lobes, and subcortical grey and white matter. Two of 14 ALS patients progressed to CI. No differences in CP measurements existed at T0 or T1 between the ALS and control groups. At T2, widespread cortical differences in MTT were present between the two groups. The ALS group had significantly increased MTT in all cortical regions, as well as the thalamus, compared with the control group. Our findings suggest early widespread changes in CP occur outside the motor area in the absence of CI in ALS.

Neuropsychological functioning in PLS: a comparison with ALS.

OBJECTIVE: In order to characterize the nature and extent of neuropsychological dysfunction in primary lateral sclerosis (PLS), we studied prospectively cognitive, emotional, and behavioral functioning in PLS, and compared performances to functioning in amyotrophic lateral sclerosis (ALS). METHODS: Eighteen patients with PLS and 13 patients with ALS completed a neuropsychological test battery assessing both cognitive skills and emotional/behavioral functioning. RESULTS: Both PLS and ALS groups scored broadly within normal limits (mean T-scores greater than 40) on all cognitive measures and no significant between-group differences were found with the exception of one variable. However, when examined on a case by case basis, the data revealed considerable heterogeneity amongst patients in both groups. Overall, 39% of PLS patients and 31% of ALS patients were considered cognitively impaired. Ahigher than expected frequency of abnormal scores was noted for several tests of executive function in both groups, and a majority of PLS patients also exhibited abnormal behavioural symptoms. There was no relationship in PLS or ALS groups between cognitive functioning and disease duration, current site of disease, site of onset, functional status, and respiratory variables. Comparison between the PLS and ALS groups indicated virtually no differences in cognitive test scores and overall emotional/behavioural symptoms. CONCLUSIONS: We observed deficits in cognition and behaviour in a significant proportion of PLS patients which were comparable to those observed in ALS cases. Although deficits were not in the range of frontotemporal dementia, both ALS and PLS cases demonstrated deficits most prominently on tests of executive functioning.

Consensus criteria for the diagnosis of frontotemporal cognitive and behavioural syndromes in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is increasingly recognized to be a multisystem disorder which includes both clinical and neuropathological features of a frontotemporal lobar degeneration (FTLD). In order to provide a common framework within which to discuss the characteristics of the cognitive and behavioural syndromes of ALS, and with which to conduct clinical and neuropathological research, an international research workshop on frontotemporal dementia (FTD) and ALS was held in London, Canada in June 2007. The recommendations arising from this research workshop address the requirement for a concise clinical diagnosis of the underlying motor neuron disease (Axis I), defining the cognitive and behavioural dysfunction (Axis II), describing additional non-motor manifestations (Axis III) and identifying the presence of disease modifiers (Axis IV).

Cerebral haemodynamic changes accompanying cognitive impairment in primary lateral sclerosis.

Our objective was to elucidate the relationship between cognitive decline and cerebral haemodynamics in patients with PLS. We examined 18 patients with PLS and contrasted both neuropsychological and cerebral perfusion findings with seven age- and education-matched non-PLS controls. PLS patients were stratified into two groups based on the number of abnormal neuropsychological test scores: 1) cognitively intact PLS patients (PLS; those having zero or one abnormal scores (n =14)), and 2) cognitively-impaired PLS patients (PLSci; those having two or more abnormal test scores (n =4)). There was considerable heterogeneity in level of cognitive functioning with four patients meeting the criteria for cognitive impairment. The findings were highly consistent with a frontotemporal lobar dysfunction. Using CT perfusion to assess cerebral haemodynamics, the PLSci group had increased cerebral blood volume (CBV) and mean transit time (MTT) with reduced cerebral blood flow (CBF). More specifically, MTT was significantly increased (p<0.05) in the PLSci group compared with controls in all regions and affected both grey and white matter, with the exception of the temporal lobe and subcortical parietal white matter. These observations suggest that a subset of PLS patients is subject to cognitive decline and that this process is associated with changes in cerebral haemodynamics.