Cognitive Impairment due to Multiple Sclerosis: symptoms, characteristics and treatment

People with multiple sclerosis may also be affected by cognitive losses.

Cognitive impairment due to multiple sclerosis is present in 40 to 65% of people with this disease and affects functions such as memory, language or executive functions.

Let us take a closer look at what this disease and the cognitive impairment it causes.

What is multiple sclerosis and how does it occur?

Multiple sclerosis is a chronic autoimmune disease of the central nervous system.. It is one of the most common neurological disorders among people in their 20s and 30s.

This disease affects the myelin or white matter of the brain (substance that surrounds and insulates the nerves) and the spinal cord, causing the appearance of sclerotic plaques that impair the normal functioning of these nerve fibers.

The immunological abnormality produced by multiple sclerosis manifests itself in symptoms such as: fatigue, lack of balance, pain, visual and cognitive disturbances, speech difficulties, tremors, tremors, etc.etc. In addition, sometimes there is a cognitive impairment that affects cognitive functions such as memory, language or executive functions.

The etiology of the disease is complex and is related to different genetic and environmental factors, such as infection by the Epstein-Barr virus, smoking, vitamin D deficiency or ultraviolet light.

Types of multiple sclerosis

The course of multiple sclerosis cannot be predicted, and the cognitive impairment it causes may vary from one individual to another and depending on the disease phenotype. and depending on the phenotype of the disease.

At present, the following multiple sclerosis phenotypes have been described:

• Isolated neurological syndrome.Isolated neurological syndrome: usually affects young individuals between 20 and 40 years of age. It is the first clinical neurological event suggestive of multiple sclerosis, lasting 24 hours. It may present a partial or total recovery, and corresponds to a single lesion in the white matter of the brain.

• Relapsing-remitting multiple sclerosisRelapsing-remitting multiple sclerosis: it is the most frequent form in the diagnosis of sclerosis. This phenotype is characterized by outbreaks interspersed with phases of remission, although its incidence decreases during the disease. Because patients do not fully recover, these episodes often result in a cumulative increase in disability.

• Secondary progressive multiple sclerosis (RRMS)Secondary progressive multiple sclerosis (SPMS): this phenotype is the one with the highest degree of disability. It occurs in about a quarter of patients with sclerosis in our country, and presents a slow neurological deterioration, with or without flare-ups. It is estimated that half of the patients with this phenotype usually evolve to this phenotype.

• Primary Progressive Multiple Sclerosis (PPMS)Patients with this phenotype of multiple sclerosis have occasional periods of stability, with little significant transient improvement, without developing flares.

Cognitive deficits in multiple sclerosis

Cognitive impairment in patients with multiple sclerosis has a major impact on their activities of daily living. The following are the main cognitive domains affected in this disease.

1. Memory

Memory is affected in 40 to 65% of patients.. The main deficit is observed in the processes of acquisition, encoding and learning of information, which is manifested, for example, when remembering names, conversations or book arguments.

Patients need a greater number of trials and repetitions to learn, although once they have learned a piece of information, performance in recall and recognition tasks is similar to that of healthy subjects.

2. Attention and speed of information processing

These cognitive functions are impaired in 20 to 25% of patients with MS.. They are impaired almost from the onset and indicate incipient cognitive impairment.

Patients present problems in maintaining and manipulating information in working memory tests, as well as in tasks that require a certain processing speed.

They also show difficulties in following a conversation, a reading or a movie, as well as in processing the information they have just seen, when the activity has already changed.

3. Executive functions

Executive functions are impaired in 15 to 20% of patients.. This impairment manifests itself in tasks that require abstract reasoning, planning, problem solving or cognitive flexibility.

On a day-to-day basis, patients have difficulties when they need to plan details of a trip, manage resources or keep an agenda, for example. They also have many problems anticipating events and changing strategies to provide solutions.

4. Language

Between 20 and 25% of patients have language impairment in multiple sclerosis.. The main difficulty is observed in verbal fluency, the ability to produce fluent spontaneous speech. This alteration also influences the impairment of recall memory, executive functions and processing speed.

Although language is affected, aphasia is not very frequent in this disease.

5. Visuospatial functions

Visuospatial functions, which are responsible for mentally representing, analyzing and manipulating objects, are affected in 10 to 10 percent of cases.are affected in 10 to 20% of patients with multiple sclerosis. The patient presents difficulties in recognizing objects, such as faces, and in performing visual relation and integration tasks and processing shapes.

Complications are also observed in spatial calculation (depth perception), which can cause problems in driving vehicles, due to altered distance perception.

Treatment of cognitive impairment in multiple sclerosis

The usual non-pharmacological treatment for multiple sclerosis patients usually includes cognitive rehabilitation, an intervention designed to improve cognitive functions and to improve the patient's cognitive function.an intervention designed to improve cognitive functions, with the aim of improving the patient's functionality.

According to scientific studies, this type of cognitive intervention brings benefits to patients, with improvements in cognitive domains such as memory and in the overall quality of life of affected individuals.

However, no definitive conclusions can be drawn about the effects of cognitive rehabilitation on the mood and quality of life of patients, because different rehabilitation techniques have been used, there has been a lack of sensitivity in the measures used to assess results, and small samples have been used.

Regarding pharmacological treatment, several studies with stimulant drugs such as amantadine, l-amphetamine or modafinil, have not yet shown conclusive data regarding their efficacy, although they have been used in this type of disease.

Drugs used in Alzheimer's disease, such as cholinesterase inhibitors, donezepil, Rivastigmine or memantine, have not shown conclusive efficacy either.

Prevention in multiple sclerosis: cognitive reserve

Cognitive reserve is our brain's ability to compensate for age-related deterioration or cognitive decline resulting from disease. This capacity is determined, to a large extent, by the brain activity previously maintained, the knowledge acquired and the good or bad habits adopted.

Recent research has shown that cognitive reserve in multiple sclerosis is a protective factor against long-term neurocognitive decline. It could modulate the severity of the symptoms of the deterioration, modifying the clinical expression of the disease itself.

Practicing daily stimulating activities that involve some cognitive effort, such as reading, physical exercise or playing intellectual games, seems to increase this cognitive reserve that modifies the clinical expression of the disease itself, seems to increase this cognitive reserve which may help multiple sclerosis patients to prevent future declines..

Bibliographic references:

• Castro P, Aranguren A, Arteche E, Otano M. Cognitive impairment in multiple sclerosis. An Sis Sanit Navar 2002; 25: 167-78.

• Olascoaga J. Quality of life in multiple sclerosis. Rev Neurol 2010; 51: 279-88.