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Some patients with ALS, a rare neurological disease, develop cognitive impairment and/or dementia. This article discusses the connection between dementia and ALS, and the symptoms, diagnosis and treatment of dementia in this patient population.

Amyotrophic lateral sclerosis (ALS) is a rare neurological disease that develops due to loss of motor neurons, which are nerve cells that control voluntary muscle movements such as walking, eating and speaking.

Dementia and ALS

Symptoms of ALS are mainly physical as patients start to lose their ability to control several different muscles. However, some patients also experience mental changes, such as the development of cognitive impairment (issues with thinking, learning, memory, and speech) and dementia.

Dementia is a neurological disorder that interferes with a patient’s ability to carry out every day activities. In patients with ALS, dementia is thought to arise due to a loss of cells in the frontal lobe (which encompasses the area of the brain from forehead to the ears). Hence, this type of dementia is known as frontotemporal dementia.

The prevalence is dementia in patients with ALS is quite rare, though it does occur across a range of ethnic groups and in both genders. Patients between the ages of 55-65 are most likely to be affected. Unfortunately, it is not known why some people develop dementia and others don’t.

Symptoms of dementia in ALS patients

There are the following symptoms of frontotemporal dementia in ALS patients:

  • A change in personality or behavior
  • Lack of interest in activities
  • Withdrawal from social engagements
  • Indifference towards previously enjoyable activities
  • Reduced emotions
  • Lack of inhibition
  • Lack of spontaneity
  • Mood swings
  • Being inappropriate in social settings
  • Hyperactivity or being restless
  • Memory loss
  • Inability to speak
  • Loss of language, either partial or complete
  • Inability to reason
  • Loss of problem solving ability
  • Develop of repetitive rituals such as hoarding, dressing, wandering, or using the bathroom
  • Overeating or having strange eating habits
  • getting stuck on certain ideas or thoughts
  • High emotional reactivity
  • Agitation
  • Lack of empathy or understanding for others
  • Slowed word-finding
  • Lost meaning of words, as in no longer recognizing what words mean or using words incorrectly in sentences

During this time, the typical symptoms of ALS continue to progress. These include weakness of limbs, swallowing problems, muscle wasting, muscle twitches and shortness of breath.

Testing for dementia in ALS patients

There are various tests that may be conducted to determine whether a patient has frontotemporal dementia. There are no lab or blood tests that can diagnose dementia but thorough neuropsychological evaluation that uses questionnaires, physical assessment, interviews and imaging are conducted. Here are the following tests:

  1. Medical interview: firstly, the physician will conduct a thorough medical interview and ask you what your symptoms are and when they began, any prior medical issues, family medical history regarding dementia, use of medication, hobbies and habits, lifestyle, work, military history and travel history.
  2. Physical examination: this will be focused on signs of ALS and other diseases that cause similar issues. The examination will also test mental status, which will include answering simple questions and following simple orders.
  3. Evaluation for depression: as depression is common in this patient population and can cause cognitive issues, physicians will also evaluate the presence of depression.
  4. Word generation tests: in word generation tests, patients are asked to come up with words in categories as quickly as possible. As this test examines the executive cognitive functions of the frontal lobe, it is a good test to determine the frontal lobe has been impacted in patients. This has been shown to be a sensitive test in identifying ALS patients with cognitive issues.
  5. Neurobehavioral Questionnaires for caregivers: often caregivers can be asked a series of questions that are part of neurobehavioral questionnaires to determine whether the patient has undergone behavioral changes. This is because the patient may lack insight or self-awareness to understand that they have undergone behavioral change.
  6. Brain scans: this is the best way to determine whether there any brain abnormalities in the patient. CT scans, which are like an x-ray but more detailed, can be used to show frontal lobe shrinkage in ALS patients with dementia. MRIs can also be conducted as they show even greater detail. Lastly, single-photon emission computer tomography is another imaging technique that can be used to show issues with brain functioning.
  7. Electroencephalography: a type of test that assess the electrical activity of a brain and can help distinguish between different causes of dementia symptoms.

Treatment for dementia in ALS patients

Unfortunately, there is no current treatment for frontal lobe dementia in patients with ALS. The currently approved treatment for ALS is riluzole (Rilutek), which has not been shown to have any effect on dementia. Another medication that is used to treat ALS, gabapentin, has also not shown any positive effects on dementia in ALS.

Here are the following drugs that can potentially help ALS patients with dementia:

  1. Cholinesterase inhibitors: these are often used in treatment of Alzheimer’s disease, another type of dementia. These include the drugs such as donepezil, rivastigmine and galantamine. However, these drugs may increase irritability in patients with frontotemporal dementia.
  2. Antidepressants: these can be used to treat behavioral changes as they can improve mood and calm the patient. Antidepressants include selective serotonin re-uptake inhibitors (SSRIs) such as fluoxetine, sertraline, paroxetine, and citalopram, as well as dopamine blockers such as olanzapine.

  • Lomen-Hoerth, Catherine, Thomas Anderson, and Bruce Miller. "The overlap of amyotrophic lateral sclerosis and frontotemporal dementia." Neurology 59.7 (2002): 1077-1079.
  • Goldstein, Laura H., and Sharon Abrahams. "Changes in cognition and behaviour in amyotrophic lateral sclerosis: nature of impairment and implications for assessment." The Lancet Neurology 12.4 (2013): 368-380.
  • Hanagasi, Hasmet A., et al. "Cognitive impairment in amyotrophic lateral sclerosis: evidence from neuropsychological investigation and event-related potentials." Cognitive Brain Research 14.2 (2002): 234-244.
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