The normal processing of emotional information is a vital element of ideal social interactions and interpersonal relationships. However, the disturbance of emotion processing is present in Amyotrophic Lateral Sclerosis (ALS).
Recent research has shown that ALS patients may encounter challenges recognising emotions in other people. This is irrespective of the fact that they may not possess other cognitive or behavioural problems.
This lack of ability to recognise emotions has been attributed to microscopic alterations in brain anatomy. That is, in parts of it associated with emotional processing which is also likened to changes observed in patients with some types of Frontotemporal Dementia (FTD) which is a fatal degenerative brain condition.
Despite the fact that FTD patients show advanced deficits in emotion perception and social cognition, these domains have been accorded little regard in ALS. To add on, direct comparisons between ALS and FTD on emotion processing tasks are lacking.
ALS is a neurological disorder that impacts on the nerve cells that are responsible for controlling muscles. The motor neurons in the brain and spinal cord are destroyed and this may lead to progressive paralysis. The voluntary muscles give rise to movements such as chewing, swallowing, walking, breathing and talking.
With the resultant death of motor neurons, ALS patients lose the ability to initiate and regulate muscle movement which is attributed to paralysis and eventually death. This occurs between two and five years after diagnosis and onset of symptoms of the disease.
ALS is a multisystem condition which is characterized by executive and behavioural symptoms in some cases. The identifiable deficits of social cognition including defective cognitive and emotional empathy have been reported in ALS patients recently. However, the neurostructural correlates of these disorders in ALS are still unknown.
The disease in its severity is known to not only impair motor abilities but also impact on cognition and emotional processing. The subjective ratings of emotional stimuli depicting social interactions and facial expressions are altered in ALS. Recognition of negative emotions and ability to mentalize other people’s motives is alleviated.
On a sad note, there are no effective treatments for ALS and this makes ALS patients dependent on medications that will alleviate symptoms such as muscle spasms and mechanical breathing aid devices. There exists no reliable therapy to stop, reverse or hinder the progression of symptoms for the neurodegenerative disease.
The study was aimed at investigating how microstructural white-matter correlates of emotional attribution impairment in a sample of non-demented patients with ALS. It was published in the journal PLOS ONE. It underscores that these changes support the idea that brain changes observed in ALS can be viewed as different levels along a continuum of changes linking ALS with FTD.
Going by scientific records, approximately 50 percent of all who develop ALS have symptoms that are not linked to movement. These symptoms are also observed in the behavioral variations of FTD. Some patients only possess a limited number of these symptoms while a significantly small percentage have the full range of symptoms known as the behavioral variant of FTD syndrome. This essentially implies that ALS and FTD occur simultaneously.
Studies that have been conducted in the past have established that some disease mechanisms involving brain changes and genetic factors also overlap between the two conditions, that is, ALS and FTD. A majority of researchers rely on the principle that the two diseases are representative of different manifestations of a disease spectrum.
The recognizing of emotional states in others is a necessity for empathy. Previous research findings have demonstrated that both ALS and FTD patients have changes in their brain anatomy that are apparent even to the naked eye.
The patients with both FTD-ALS and FTD exhibit similar and significant impairments in emotional processing. By contrast, ALS patients without FTD show preserved emotion processing. Performance on emotion processing tasks may provide a useful clinical tool in identifying those with early FTD-ALS research has established.
The researchers from Italy at the Vita-Salute San Raffaele University in undertaking the study assessed whether ALS patients without FTD also had microscopic brain changes in significant brain regions.
The study mobilized 13 patients who had either been diagnosed or had suspected ALS. Also, 14 healthy people were recruited as controls. Prior to the experiments, all ALS patients were screened for cognitive and behavioral symptoms which consisted of language, memory and executive functions. This was because, cognitive extra-motor impairments in ALS may comprise of language, memory and executive abilities with the major behavioral symptom being apathy.
All ALS cases had no known family history of the disease. To add on, the patients were screened from time to time for pathogenic mutations in certain genes linked to ALS development. However, none of the patients carried any mutations.
All the participants of the study underwent a structured clinical interview, a full neurological examination, and a Magnetic Resonance Imaging (MRI) investigation. They had their brains scanned using a MRI technique known as Diffusion Tensor Imaging. It was responsible for measuring the microscopic features of the brain’s white matter.
This method was seen to offer productive suggestions regarding the impairment of distinct social cognition networks in ALS and heighten understanding of the pathological continuum associating ALS with FTD. While conducting the brain scans, the participants engaged in two activities to establish if they were in a position to recognize the emotional state of another person or people.
Going further into the study, all the participants completed a standard neuropsychological evaluation to assess the presence of cognitive and behavioural impairments. More precisely, the researchers focused on:
On the basis of presence or absence of cognitive and behavioural impairments, the researchers were able to point out 2 patients with difficulties in executive functions and 2 patients with behavioural problems such as apathy, irritability and self-control loss. The 9 patients remaining who took up 70 percent were regarded as pure ALS patients as they were cognitively and behaviourally unimpaired. Thus, there was lack of establishment of the presence of behavioural dysfunctions.
In comparison to healthy people, ALS patients had more difficulties in understanding the emotions and intentions of others. On the other hand, when researchers observed the nine patients without notable behavioural and cognitive difficulties, a lower ability to recognize emotions was established. However, the recognition of intentions was not impaired in any way whatsoever.
It has been proposed that extra-motor impairments in ALS, including those affecting empathic abilities could be attributed to the involvement of mirror system networks. More specifically, such an impairment may be as a result of a breakdown in the so called automatic resonance mechanism leading to an indirect sharing of another person’s feelings. This is accomplished by coding a representation based on the bodily state of that person at a particular point in time.
The major drawbacks linked to the study were:
The research team established that the study gave the idea that an impairment in empathic processing may occur in some ALS cases, even in absence of deficits in other cognitive domains, that is, pure ALS patients.
The above evidence acknowledges that social cognition deficits in non-demented ALS patients are a consequence of executive impairment. In addition, that they show the failure in the ability to associate mental states to another person may be independent from the presence of additional extra-motor impairments.
Of more importance, is that the overall attribution deficit emerged in ALS patients was reinforced by a distinct alteration in emotional empathy proposing a decline in the ability to identify emotional states and intentions in others.
The fatality of the difficulties could be associated with measures of microscopic changes in several brain areas linked to emotional processing. This was indicative of the fact that problems in recognizing emotions may occur in ALS patients even without other cognitive or behavioral challenges.
On the plus side, the study demonstrated proof-of-concept geared at suppling preliminary and exploratory data for future studies. Going by reports, there exists no prior information on the correlation between white matter destruction and social and emotional processing disorders in ALS.
In spite of the fact that further studies are necessary to confirm the findings from the above-mentioned study, the results feature significant outcomes on the clinical front. The likelihood of occurrence of social and emotional impairments in early stages of ALS gives rise to serious issues regarding necessity for effective supporting programs for ALS patients and caregivers.
Going forward, a comprehensive assessment of different aspects of non-motor such as behavioural, cognitive and socio-emotional deficits in ALS patients is required. This will facilitate the enhancement of diagnostic accuracy and in the process, support the training of caregivers alongside coping and management strategies.