Patients with amyotrophic lateral sclerosis (ALS) but without dementia had behavioral declines and retained varying levels of insight into this decline, while premorbid verbal intelligence was associated with worse insight into cognitive decline in the ALS population, according to study findings published in Brain and Behavior.

Previous research suggests loss of “insight,” or, the loss of awareness of behavioral impairment, is prevalent in ALS-frontotemporal dementia (ALS-FTD), while patients with ALS without FTD are able to retain this awareness. According to the researchers, loss of insight has not been investigated across the ALS-FTD group. The objective of the current study was to assess the loss of insight related to behavioral changes across cognitive profiles in ALS subgroups.

The study recruited 83 patients with ALS and their family members from outpatient clinics in Germany. All participants completed the Frontal Systems Behavior Scale, which assessed apathy, disinhibition, and executive dysfunction.


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Using the Strong and Rascovsky criteria, researchers classified patients into 5 groups: cognitively unimpaired (ALSni; n=33), cognitively impaired without dementia (ALSci; n=12), behaviorally impaired (ALSbi; n=26), a combination of behaviorally and cognitively impaired (ALScbi; n= 8), and ALS-frontotemporal dementia (ALS-FTD; n=4). The investigators examined whether subgroup differences existed regarding participants’ insight into behavioral decline.

Across subgroups, ages ranged between 59 and 67 years, while disease durations ranged between 20 and 31 months. The ALScbi group reported clinically relevant impairments across the apathy and total behavioral change domains, but these impairments were not reported in the other subgroups. Behavioral impairment in patients with ALScbi occurred before motor onset. Self-reports of “statistically relevant subclinical increases in behavioral abnormality” were observed in all patients across apathy and total behavioral change domains, according to the researchers.

Patients with ALSni also self-reported increased disinhibition, while patients with ALScbi reported increased disinhibition along with executive dysfunction. Patients with ALS-FTD self-reported increased executive dysfunction.

In post hoc tests, there was moderate evidence that showed patients with ALS-FTD retained worse insight into disinhibition compared with patients with ALSci (BF-0 = 4.32, W = 1.00, Rˆ = 1.01). Only patients with ALS-FTD lost insight into disinhibition and executive dysfunction. In addition, patients with ALSbi had worse insight than patients with ALSni and ALSci (Bayes factor >10). Worse insight was associated with higher IQ (Bayes factor >3).

The researchers noted that the small number of patients with ALS-FTD in this study who were capable of self-rating represents a potential study limitation. According to the researchers, it is possible that loss of insight in these patients “would have been more apparent in those who could no longer self-rate.”

Disclosure: Multiple authors declared affiliations with the pharmaceutical industry. Please refer to the original article for a full list of disclosures.

Reference

Temp AGM, Kasper E, Vielhaber S, et al. Loss of “insight” into behavioral changes in ALS: Differences across cognitive profilesBrain Behav. Published online December 2, 2021. doi:10.1002/brb3.2439