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Frontotemporal Dementia

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Overview

Frontotemporal dementia (FTD) describes a group of clinical syndromes that are characterised by progressive degeneration of the frontal and anterior temporal lobes.

After Alzheimer’s disease, it is the second most common dementia to occur in adults <65 years of age.

The onset of FTD is typically between 45 and 65 years.

This section is a summary of FTD.

Types

Overview

There are different types of FTD:

  • Behavioural variant FTD (BvFTD, Pick’s disease) – the most common type:
    • Characterised by behavioural changes such as impulsivity, apathy, and disinhibition
  • Primary progressive aphasia (PPA):
    • Semantic variant PPA (svPPA):
      • Loss of semantic understanding (meaning and context of information), impaired word comprehension
      • Speech remains fluent and grammatical
    • Non-fluent variant PPA (nfvPPA):
      • Progressive difficulties in fluency and grammar

Epidemiology

  • Overall less common than Alzheimer’s disease and vascular dementia but is the second most common type in those under 65s
  • Onset usually between 45 and 65 years
  • Around 10% of cases are linked with an autosomal dominant mutation

Risk Factors & Associations

Presentation

Symptoms tend to be insidious and progress gradually. There are three main overall syndromes. They are defined by the most predominant symptom at presentation:

  • Behavioural variant frontotemporal dementia
    • The most common type
    • Disinhibition and inappropriate social behaviour
    • Anhedonia but no signs of depression
    • Apathy
    • Difficulties with planning, organising, and decision making
    • Lack of insight
    • In later stages, primitive reflexes may return
    • Echolalia or mutism
  • Progressive non-fluent aphasia
    • Slow and hesitant speech
    • Grammatical errors in speech
    • Impaired understanding of complex sentences
  • Semantic dementia
    • Loss of vocabulary with fluency of speech retained
    • Asking what familiar words mean
    • Difficulty finding the right word and talking around it or describing it
    • Difficulty recognising familiar faces or objects

Differential Diagnoses

Alzheimer’s disease

  • In FTD there is relative preservation of memory compared to Alzheimer’s disease

Vascular dementia

  • Cognitive decline is stepwise in vascular dementia
  • Vascular dementia may have associated focal neurological deficits
  • It may mimic FTD as the two can have personality changes and disinhibition

Dementia with Lewy bodies

  • Cognition fluctuates
  • Features of Parkinsonism may be present
  • Visual hallucinations are rare in FTD

Depression

  • Anhedonia is present along with features of depression such as hopelessness, suicidal thoughts, insomnia, pessimistic mental states

Normal pressure hydrocephalus

  • There is classically a triad of:

Assessment

Screening tools

Cognitive assessment tools in a non-specialist setting include:

  • 10-point Cognitive Screener (10-CS)
  • 6-item Cognitive Impairment Test (6-CIT)
  • 6-item Screener
  • Memory Impairment Screen (MIS)
  • Mini-Cog
  • Test Your Memory (TYM)

Dementia should not be ruled out solely based on a normal cognitive assessment test.

Investigations

Initial investigations in primary care

Initial investigations are to rule out possible reversible causes of symptoms:

Other investigations may need to be considered if appropriate:

  • Chest x-ray
  • ECG
  • Urine microscopy and culture
  • Urine toxicology panel for opiates, cocaine, benzodiazepine and cannabinoids
  • Syphilis serology
  • HIV testing

Referral to secondary care

If the person is severely disturbed, arrange admission to hospital. Detention under the Mental Health Act (1983) may be needed.

If dementia is suspected in people with learning disabilities arrange a specialist referral for assessment and treatment.

People with MCI are followed up regularly and referred to secondary care if their symptoms deteriorate.

All other patients should be referred to a memory assessment service for specialist assessment and management.

Investigations in secondary care

Specialist investigations involve neuroimaging to screen for reversible structural causes (e.g. subdural haematoma). These may include:

  • MRI/CT head:
    • Neuroimaging may also show focal atrophy in the frontal and/or anterior temporal lobes.

If the diagnosis is uncertain, the following may be used:

  • Brain fluorodeoxyglucose (FDG)-positron emission tomography (PET):
    • Shows reduced metabolism of the frontal and/or anterior temporal lobes
  • Brain perfusion single-photon emission computed tomography (SPECT):
    • Shows reduced perfusion of the frontal and/or anterior temporal lobes

Management

There is no treatment to stop the progression. Acetylcholinesterase inhibitors or memantine should not be used. Management is aimed at relieving symptoms.

Monitoring

  • Monitoring is on a case-by-case basis. Often, patients are followed up every 6 months to look for functional or cognitive declines. Home safety risks should also be assessed at these visits

Patient Advice

  • Discussions regarding future care i.e. lasting power of attorney, advance decisions, place of death, and wills should take place with the patient and their family and carers at an early stage.
  • Patients should stop smoking, reduce alcohol consumption, and eat a healthy balanced diet to reduce the risk of dementia or further decline, and to reduce the risk of frailty
  • When communicating with patients, family and carers etc. should use short and simple sentences and provide response choices to avoid confusion
  • Coping techniques should also be discussed with family and carers etc. of the patient.
  • Legal information surrounding driving should be given.
  • Financial crises may arise from spending or gambling. Carers should try to limit the amount the patient spends.

Complications

  • Falls
  • Financial problems e.g. excess gambling
  • Legal problems e.g. aggressive behaviour or socially inappropriate behaviour

Prognosis

  • Average survival is around 8-10 years
  • The syndromes tend to converge as the disease progresses

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