Loss of "insight" into behavioral changes in ALS: Differences across cognitive profiles

Area of Science:

• Neuroscience
• Neurology
• Behavioral Science

Background:

• Behavioral impairment is a known feature of amyotrophic lateral sclerosis (ALS) and ALS-frontotemporal dementia (ALS-FTD).
• A key distinction proposed is that ALS patients without FTD retain insight into their behavioral deficits, while ALS-FTD patients lose this insight.
• Previous research has not comprehensively examined insight across the full spectrum of ALS cognitive-behavioral profiles.

Purpose of the Study:

• To investigate the extent of behavioral decline in ALS patients across different cognitive-behavioral profiles.
• To determine if and how insight into behavioral impairment differs among these ALS subgroups.
• To explore the relationship between cognitive status, behavioral changes, and insight in ALS.

Main Methods:

• A bicentric study included 83 ALS patients and their informants from two German sites.
• Patients and informants completed the Frontal Systems Behavior Scale assessing apathy, disinhibition, and executive dysfunction.
• Patients were categorized into five groups: cognitively unimpaired (ALSni), cognitively impaired without dementia (ALSci), behaviorally impaired (ALSbi), cognitively and behaviorally impaired (ALScbi), and ALS-FTD, using Strong and Rascovsky criteria.
• Bayesian two-way ANOVA was used to analyze subgroup differences in insight.

Main Results:

• All ALS patient subgroups demonstrated behavioral decline.
• Loss of insight was specifically observed in ALS-FTD patients concerning disinhibition and executive dysfunction.
• Patients with behavioral impairment (ALSbi) showed poorer insight compared to cognitively unimpaired (ALSni) and cognitively impaired without dementia (ALSci) groups.
• Higher premorbid IQ was unexpectedly associated with worse insight into behavioral decline.

Conclusions:

• ALS patients without dementia exhibit behavioral decline irrespective of their specific cognitive-behavioral profile.
• Varying degrees of insight into behavioral decline are retained by ALS patients without dementia.
• The inverse correlation between premorbid verbal intelligence and insight warrants further investigation.