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Physicians and researchers have started to increasingly recognize that thinking and behavior are affected in ALS. This article outlines the cognitive changes patients experience, causes, risk factors, diagnosis and recommendations for caregivers.

The primary symptoms of Amyotrophic Lateral Sclerosis (ALS) are physical, particularly related to the loss of voluntary muscle control. However, over the last decade, physicians and researchers have started to increasingly recognize that thinking and behavior are affected in ALS.

As the symptoms of ALS differ among individuals, some ALS patients will not experience changes in thinking or behavior. Conversely, some patients will develop minor changes in their thinking and behavior and will still able to function on their own and make their own informed decisions.

Finally, there will be some patients that will experience significant changes in thinking and behavior to the point where they cannot make their own informed decisions about their care and may require others to make decisions on their behalf.

ALS statistics

Studies have shown that up to 50% of patients with ALS will never develop significant changes in their thinking or behavior (aside from the normal psychological reaction to their disease). However, up to 50% of people with ALS will experience at least some changes in their thinking or behavior. Finally, approximately 25% of patients that develop cognitive issues will actually develop dementia such as frontal lobe dementia (FTLD), a progressive condition involving selective degeneration of the frontal and anterior temporal lobes of the brain.

What are cognitive changes in ALS patients?

While each patient will experience a set of different symptoms depending on their disease, there are certain symptoms that are commonly seen when cognition is impaired in ALS:

  • Embarrassing, child-like behavior
  • Inattention
  • Loss of a “filter” with regards to expressing opinions
  • Slowed thinking
  • A patient will start to only eat one type of food consistently as opposed to a more balanced diet
  • Repetitive behaviors
  • Loss of table manners
  • Reduced attention to hygiene (i.e. bathing, grooming, or changing clothes)
  • Loss of judgment with regards to making decisions
  • Lack of concern for oneself or others, apathy
  • Inability to concentrate
  • Fixation on a single idea or activity
  • Increased aggression
  • Issues communicating
  • Writing or speaking words in the wrong order
  • Loss of ability to spell correctly
  • Unable to follow instructions
  • Difficulty remembering what the patient intends to do
  • Loss of reasoning or problem-solving ability

What are the causes of cognitive problems in ALS patients? 

While issues relating to cognition in ALS can be due to the manifestation of the disease, it can also be related to other factors such as:

  • Insufficient breathing (too little oxygen or too much carbon dioxide is getting to the brain)
  • Side effects from medication
  • Depression or anxiety
  • Sleep disturbance
  • Pre-existing psychiatric disease.

ALS patients need to be brought these symptoms to the attention of medical providers so that they assess the cause of the impairment and treat if possible.

What are the risk factors for cognitive issues in ALS? 

While there are certain risk factors that can predispose individuals to develop cognitive impairment in ALS, individuals without these factors can also develop the disease. Some of these risk factors include:

  • Older age
  • Bulbar onset disease (where ALS affects the voice and swallowing before the limbs)
  • A family history of dementia
  • Pre-ALS brain injury
  • Poor breathing
  • Specific mutations on chromosomes 17 or 9
Currently, the only risk factor that researchers have discovered that consistently predisposes ALS patients to develop cognitive or behavioral issues is the presence of a mutation in a gene called C9ORF72.

Diagnosis of cognitive and behavioral symptoms in ALS

In order to assess the presence of cognitive and behavioral symptoms in ALS, the patient will be referred to a neuropsychologist for cognitive evaluation. The neuropsychologist will administer various paper and pencil tests to determine how the patient processes information.

The results will be compared to data from people of the same age and education level. This helps to determine if there are any cognitive issues and what type they could be. The neuropsychologist may also choose to speak with the patient or a caregiver or a person who knows the patient well.

What are the consequences of cognitive issues?

Some studies have shown that patients that develop cognitive and/or behavioral impairment in ALS live a shorter life span than people without this type of ALS impairment.

At this time, there are many studies that are trying to determine whether the presence of cognitive/behavioral impairment impacts the effectiveness of medicines, therapies, or other procedures in ALS management.

What is pseudobulbar affect?

Some ALS patients go on to develop an unusual symptom called the pseudobulbar affect, in which the patient may cry or laugh at inappropriate times. Essentially, once the patient starts feeling an emotion, it is difficult to shut it off.

Pseudobulbar affect is a common symptom of ALS and is the result of a brain reflex that is no longer working correctly. Pseudobulbar affect does not necessarily mean that a person is feeling apprehensive, unhappy, depressed, or emotionally distraught. ALS patients can have pseudobulbar effect and no other cognitive, behavioral, or neuropsychological symptoms.

What are recommendations for caregivers of patients with ALS that develop cognitive or behavioral impairment:

  • Educate yourself on the disease and the impact of cognitive impairment
  • Take care of yourself
  • Make communication with the patient easier by shortening sentences into smaller phrases, asking simple yes or no questions and slow down when talking with the patient
  • Provide supervision and attend all medical appointments with the patient to make sure information is accurately relayed
  • Set realistic expectations for the person with ALS
  • Make decisions regarding health-care and finances early on in the disease progression
  • Continue to enjoy relationships that bring happiness and take breaks from relationships that are stressful
  • Continue to enjoy activities with the patient that are enjoyable and can be conducted safely
  • Abstain from activities that are stressful or can result in any sort of injury

ALS and dementia

As mentioned earlier, approximately 25% of patients that develop cognitive issues will go on to develop dementia, which is defined as a group of symptoms related to a decline in memory or other thinking skills that are severe enough to impede a person's ability to perform everyday activities.

Dementia symptoms in ALS usually manifest as changes in personality or behavior. However, these other symptoms are also common:

  • A lack of interest and withdrawal from society
  • Lack of emotion and inhibition
  • Anxiety or hyperactivity
  • Inappropriate behavior in social settings
  • Mood swings
  • Loss of memory
  • Loss of speech (which is also attributed to muscle symptoms of ALS)
  • Reduction in problem-solving ability
  • Repetitive behaviors
  • Overeating or strange eating habits

Diagnosis of dementia

Dementia cannot be diagnosed using blood tests. Imaging of the brain is the best method of determining the presence of dementia. However, there are other tests that can also be conducted to diagnose dementia in ALS:

  • CT scan: Uses X-rays to show brain images
  • MRI scan: Uses magnets to show the brain in great detail
  • Single-photon emission computed tomography: Can be used to show brain functioning problems
  • Electroencephalography: Measures electrical activity of the brain
  • Electromyography: Measures signaling from brain to muscles

Treatment of dementia

While there are no specific treatments that are available for dementia, there are treatments that can help relieve symptoms. These include:

  • Edaravone (Radicava) and riluzole (Rilutek) can help with memory
  • Gabapentin (Neurontin) can help agitation in some types of dementia
  • Cholinesterase inhibitors to improve nerve signaling
  • Anti-depressants for improving mood
  • Anti-psychotic medication for treating psychosis

  • Strong, Michael J., et al. "A prospective study of cognitive impairment in ALS." Neurology 53.8 (1999): 1665-1665.
  • Ringholz, G. M., et al. "Prevalence and patterns of cognitive impairment in sporadic ALS." Neurology 65.4 (2005): 586-590.
  • Abrahams, Sharon, P. N. Leigh, and L. H. Goldstein. "Cognitive change in ALS A prospective study." Neurology 64.7 (2005): 1222-1226.
  • Wilson, C. M., et al. "Cognitive impairment in sporadic ALS A pathologic continuum underlying a multisystem disorder." Neurology 57.4 (2001): 651-657.
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