The Characteristics of Cognitive Impairment in ALS Patients Depend on the Lateralization of Motor Damage

The Spectrum of Cognitive Dysfunction in Amyotrophic Lateral Sclerosis: An Update

Cognitive dysfunction is an important non-motor symptom in amyotrophic lateral sclerosis (ALS) that has a negative impact on survival and caregiver burden. It shows a wide spectrum ranging from subjective cognitive decline to frontotemporal dementia (FTD) and covers various cognitive domains, mainly executive/attention, language and verbal memory deficits. The frequency of cognitive impairment across the different ALS phenotypes ranges from 30% to 75%, with up to 45% fulfilling the criteria of FTD. Significant genetic, clinical, and pathological heterogeneity reflects deficits in various cognitive domains. Modern neuroimaging studies revealed frontotemporal degeneration and widespread involvement of limbic and white matter systems, with hypometabolism of the relevant areas. Morphological substrates are frontotemporal and hippocampal atrophy with synaptic loss, associated with TDP-43 and other co-pathologies, including tau deposition. Widespread functional disruptions of motor and extramotor networks, as well as of frontoparietal, frontostriatal and other connectivities, are markers for cognitive deficits in ALS. Cognitive reserve may moderate the effect of brain damage but is not protective against cognitive decline. The natural history of cognitive dysfunction in ALS and its relationship to FTD are not fully understood, although there is an overlap between the ALS variants and ALS-related frontotemporal syndromes, suggesting a differential vulnerability of motor and non-motor networks. An assessment of risks or the early detection of brain connectivity signatures before structural changes may be helpful in investigating the pathophysiological mechanisms of cognitive impairment in ALS, which might even serve as novel targets for effective disease-modifying therapies.

A comparative study of cognitive and behavioral profiles between sporadic and type 8 amyotrophic lateral sclerosis

INTRODUCTION/AIMS

Amyotrophic lateral sclerosis (ALS) type 8 (ALS8) is caused by VAPB gene mutations. The differences between neuropsychological and behavioral profiles of patients with sporadic ALS (sALS) and those with ALS8 are unclear. We aimed to compare cognitive performance and behavioral aspects between sALS and ALS8 patients.

METHODS

Our study included 29 symptomatic ALS8 patients (17 men; median age 49 years), 20 sALS patients (12 men; median age 55 years), and 30 healthy controls (16 men; median age 50 years), matched for sex, age, and education. Participants underwent neuropsychological assessments focused on executive functions, visual memory, and facial emotion recognition. Behavioral and psychiatric symptoms were evaluated using the Hospital Anxiety and Depression Scale and the Cambridge Behavioral Inventory.

RESULTS

Clinical groups (sALS and ALS8) exhibited lower global cognitive efficiency and impaired cognitive flexibility, processing speed, and inhibitory control compared with controls. ALS8 and sALS showed similar performance in most executive tests, except for poorer verbal (lexical) fluency in those with sALS. Apathy, anxiety, and stereotypical behaviors were frequent in both clinical groups.

DISCUSSION

sALS and ALS8 patients demonstrated similar deficits in most cognitive domains and had comparable behavioral profiles. These findings should be considered in the care of patients.

Potential role of vitamin D levels in amyotrophic lateral sclerosis cognitive impairment

Cognitive impairment (CI) is common in amyotrophic lateral sclerosis (ALS): a keystone is identifying factors that could potentially modify the CI course. In recent years, vitamin D is becoming a potential modificatory factor for CI in many neurological disorders. This study aimed to highlight if vitamin D deficiency correlated with CI and clinical features in a cohort of ALS patients. We included 55 ALS patients with a neuropsychological evaluation (classified with the Strong Criteria) and a vitamin D dosage at the diagnosis. We also reviewed medical records and completed data for medical history, physical and neurological examination, and functional scales. At the diagnosis, 30 patients (54%) had CI. Most patients (82%) displayed low vitamin D levels (19.87 ± 9.80 ng/ml). Comparing the vitamin D level between patients with and without CI, we observed significantly lower values in the first group (15.8 ± 8.2 vs. 22.0 ± 9.7 ng/ml, p: 0.04). In the spinal female subgroup (n = 15), we found an inverse correlation between vitamin D and bizarreness score in the cognitive estimates test (r = 0.58; p: 0.04) and a positive correlation with the Corrected Raven's Standard Progressive Matrices (r = 0.53, p: 0.04). Conversely, in the bulbar female group, we observed a correlation with the corrected direct span (r = 0.84, p: 0.03). With the log-rank survival analysis, we found that the patients with vitamin D < 10 ng/ml had a shorter disease duration (Chi: 5.78, p: 0.02). Our results indicate that levels of vitamin D can influence the cognitive status of people living with ALS and that severe deficits might be an adverse prognostic survival factor.

Prevalence and determinants of language impairment in non-demented amyotrophic lateral sclerosis patients

BACKGROUND AND PURPOSE

This study aimed at estimating the prevalence of language impairment (LI) in a large, clinic-based cohort of non-demented amyotrophic lateral sclerosis (ALS) patients and assessing its underpinnings at motor and non-motor levels.

METHODS

Non-demented ALS patients (N = 348) underwent the Edinburgh Cognitive and Behavioural ALS Screen (ECAS), as well as an assessment of behavioural/psychiatric and motor-functional features. The prevalence of LI was estimated based on the proportion of patients showing a performance below the age- and education-adjusted cut-off on the ECAS-Language. Multiple regression models were run to assess the determinants of language functioning and impairment.

RESULTS

The prevalence of LI was 22.7%. 46.6% of the variance of ECAS-Language scores remained unexplained, with only the ECAS-Executive positively predicting them (p < 0.001; η²  = 0.07). Similarly, only a lower score on the ECAS-Executive predicted a higher probability of a below cut-off ECAS-Language performance (p < 0.001). Spelling and Naming tasks were the major drivers of ECAS-Language performance.

CONCLUSIONS

This study suggests that, in non-demented ALS patients, LI occurs in ≈23% of cases, is significantly driven by executive dysfunction but, at the same time, partially independent of it and is not associated with other motor or non-motor features.

Cognition and motor phenotypes in ALS: a retrospective study

Background

Amyotrophic lateral sclerosis (ALS) is phenotypically heterogeneous in motor manifestations, and the extent of upper vs. lower motor neuron involvement is a widespread descriptor. This study aimed to examine cognition across different ALS motor phenotypes.

Methods

ALS patients (N = 124) were classified as classical (N = 66), bulbar (N = 13), predominant-upper motor neuron (PUMN; N = 19), and predominant-lower motor neuron (PLMN; N = 26) phenotypes. Cognition was assessed with the Edinburgh Cognitive and Behavioural ALS Screen (ECAS) and function with the ALS Functional Rating Scale—Revised (ALSFRS-R). Revised ALS-FTD consensus criteria were applied for cognitive/behavioral phenotyping.

Results

Defective ECAS-total scores were detected in all groups — bulbar: 15.4%, classical: 30.3%, PLMN: 23.1%, and PUMN: 36.8%. Classical and PUMN ALS patients performed worse than PLMN ones on ECAS-total, ALS-specific, Fluency, and Executive measures. No other difference was detected. Worse ASLFRS-R scores correlated with poorer ECAS-total scores in classical ALS patients.

Conclusions

Frontotemporal cognitive deficits are more prevalent in PUMN and classical ALS and linked to disease severity in the latter, but occur also in PLMN phenotypes.

Supplementary information

The online version contains supplementary material available at 10.1007/s10072-022-06157-x

Upper motor neuron dysfunction is associated with the presence of behavioural impairment in patients with amyotrophic lateral sclerosis

BACKGROUND AND PURPOSE

Increasing evidence shows that approximately half of patients with amyotrophic lateral sclerosis (ALS) display cognitive (ALSci) or behavioural (ALSbi) impairment, or both (ALScbi). The aim of our study was to assess whether the burden of upper and lower motor neuron involvement is associated with the presence of cognitive and behavioural impairment.

METHODS

A single-centre retrospective cohort of 110 Italian ALS patients was evaluated to assess correlations between motor and cognitive/behavioural phenotypes. Upper motor neuron regional involvement was measured with the Penn Upper Motor Neuron Score (PUMNS), whilst lower motor neuron signs were assessed using the Lower Motor Neuron Score. The Edinburgh Cognitive and Behavioural ALS Screen-Italian version and the Frontal Behaviour Inventory were administered to evaluate patients' cognitive and behavioural profiles.

RESULTS

The PUMNS at first visit was significantly higher in behaviourally impaired ALS patients (ALSbi and ALScbi) compared to behaviourally unimpaired individuals (ALS and ALSci) (9.9 vs. 6.9, p = 0.014). Concerning the different Frontal Behaviour Inventory subdomains, higher PUMNS correlated with the presence of apathy, emotive indifference, inflexibility, inattention, perseveration and aggressiveness.

CONCLUSION

To our knowledge, this is the first study showing that a clinical prominent upper motor neuron dysfunction is associated with a more significant behavioural impairment in ALS patients, suggesting the hypothesis of a preferential spreading of the pathology from the motor cortex to the ventromedial prefrontal and orbitofrontal cortex in this group of patients.

Cognitive and social cognition deficits in Huntington's disease differ between the prodromal and the manifest stages of the condition: A scoping review of recent evidence

OBJECTIVE

Huntington's disease (HD) is a dramatic neurodegenerative disorder encompassing severe motor symptoms coupled to significant cognitive and social cognition deficits. However, it is not clear whether and how patients' neuropsychological profile changes between the prodromal and the manifest stages of the condition. The aim of the present in-depth review is to consider cognitive and social cognition impairment in HD patients by differentiating deficits arising before diagnosis from those evident from the manifest phase onwards.

METHODS

Electronic databases were searched between January 1^st , 2010 and December 31^st , 2020 by using multiple combinations of keywords related to the investigation of neuropsychological profile in HD for preliminary search, and by defining strict selection criteria for studies to be included.

RESULTS

Forty-two studies were included. Evidence suggests that the neuropsychological profile in HD reflects a complex pathological spectrum of deficits. It includes impairment in the realms of executive functions, memory, attention, information processing, and social cognition. Interestingly, patients' profiles differ significantly between the manifest and the prodromal stages of their condition, not only in quantitative terms but also from a qualitative point of view.

CONCLUSIONS

Researchers and clinicians should thus include in clinical routine timely and specific neuropsychological assessments in order to monitor patients' cognitive status as time goes by, with the ultimate goal to implement effective clinical management strategies.

PRACTITIONER POINTS

The neuropsychological profile in HD encompasses a complex pathological spectrum of deficits. Patients' profiles differ significantly between the manifest and the prodromal stages of their condition. Clinicians should include in everyday practice a timely and specific neuropsychological assessment. Detecting patients' cognitive status during the early stages of the condition already can contribute significantly to implement effective clinical management strategies.

Cognitive and Behavioral Manifestations in ALS: Beyond Motor System Involvement

Amyotrophic lateral sclerosis (ALS) has long been considered to be a purely motor disorder. However, it has become apparent that many ALS patients develop cognitive and behavioral manifestations similar to frontotemporal dementia and the term amyotrophic lateral sclerosis-frontotemporal spectrum disorder (ALS-FTSD) is now used in these circumstances. This review is intended to be an overview of the cognitive and behavioral manifestations commonly encountered in ALS patients with the goal of improving case-oriented management in clinical practice. We introduce the principal ALS-FTSD subtypes and comment on their principal clinical manifestations, neuroimaging findings, neuropathological and genetic background, and summarize available therapeutic options. Diagnostic criteria for ALS-FTSD create distinct categories based on the type of neuropsychological manifestations, i.e., changes in behavior, impaired social cognition, executive dysfunction, and language or memory impairment. Cognitive impairment is found in up to 65%, while frank dementia affects about 15% of ALS patients. ALS motor and cognitive manifestations can worsen in parallel, becoming more pronounced when bulbar functions (affecting speech, swallowing, and salivation) are involved. Dementia can precede or develop after the appearance of motor symptoms. ALS-FTSD patients have a worse prognosis and shorter survival rates than patients with ALS or frontotemporal dementia alone. Important negative prognostic factors are behavioral and personality changes. From the clinician's perspective, there are five major distinguishable ALS-FTSD subtypes: ALS with cognitive impairment, ALS with behavioral impairment, ALS with combined cognitive and behavioral impairment, fully developed frontotemporal dementia in combination with ALS, and comorbid ALS and Alzheimer's disease. Although the most consistent ALS and ALS-FTSD pathology is a disturbance in transactive response DNA binding protein 43 kDa (TDP-43) metabolism, alterations in microtubule-associated tau protein metabolism have also been observed in ALS-FTSD. Early detection and careful monitoring of cognitive deficits in ALS are crucial for patient and caregiver support and enable personalized management of individual patient needs.