1st February 2024

Frontotemporal Dementia

Background

It is a rare form of dementia. It is a progressive neurodegenerative cognitive decline, which constitutes approximately around 2% of all cases of dementia. It is a condition characterised by deterioration of personality and cognitive issues. There is evidence of atrophy in the frontal and temporal lobes.

It is generally characterised by difficulties in thinking and behaviour. They usually present with unusual and unwarranted behaviours, emotional problems, difficulties in communication (speech and language), motivation and preservative behaviours.

Epidemiology

• Unlike Alzheimer’s dementia, this is higher in males.
• It is a disease of middle-aged and older people.
• It constitutes 2% of all cases of dementia

Pathophysiology

There is prominent frontal and temporal lobar atrophy.

FTD is a broad term that includes a few subtypes:

1. Behavioural FTD or frontal variant FTD (bvFTD) – 60% of patients with FTD have this type of behavioural FTD. It causes changes in judgement, personality, behaviour and emotions. Behavioural changes are seen initially.
2. Semantic dementia or primary progressive aphasia: (sv FTD or PPA): Here, mainly there is language difficulty (speech production is spared). However, during early stages, the other aspects such as judgement, behaviour and personality are not disabled; during later stages, they are impacted.
3. Progressive non-fluent Aphasia (PNFA): Here mainly there is language difficulty- mainly speaking. Grammar is affected more so in PNFA.
4. Progressive Supranuclear palsy: This involves the brainstem, frontal cortex and basal ganglia.
5. Corticobasal degeneration: This is a neurodegenerative disorder classified as an atypical Parkinsonian syndrome
6. FTD with Motor Neuron disease: Early cognitive and behavioural changes with MND

Risk factors

• No specific risk factors. 
• Men and women are equally affected
• More likely to run in families

Clinical features

• General symptoms of behavioural variant FTD:
  • Behavioural changes:
    • Making inappropriate comments
    • Overfamiliar, socially disinhibited
    • Impulse-losing inhibitions
    • Commenting on others’ appearances, being insensitive and rude, staring
    • Sexual gestures in public
    • Aggressive verbally, physically
  • Changes in food and drinking behaviours: Overeating, craving sweet food, poor table manners, drinking excessively, and not knowing when to stop eating or drinking.
  • Poor organising skills, planning and decision-making.
  • Poor insight- lack of awareness of changes in themselves (Anosognosia)
  • Poor empathy- fail to understand others and less considerate of their feelings (alexithymia)
  • Poor motivation to do things, anhedonia
  • Reduced concentration and ability to focus (gets distracted easily)
  • Repetitive and or obsessive behaviours- Repeating phrases, gestures, hoarding
• Semantic variant PPA:
  • Although this mainly involves language, other FTD symptoms might present too
    • They lose their vocabulary over the days: Initially complicated words and then later simple ones.
    • They may forget the functions of familiar objects: The use of fridge, microwave
    • Loss of skill to use simple objects in day-to-day life: use of comb, toothbrush
• Non-fluent variant PPA:
  • Although this mainly involves language, other FTD symptoms might be present too. As the name suggests, the problem is in speaking fluently
    • Poor grammatical sentences (agrammatism)
    • Short telegraphic speech, sound errors
    • Saying the opposite of what they want to
    • They might understand a particular word but not when in a sentence
• Late stages of FTD:
  • Cognitive impairment
  • Psychotic symptoms
  • BPSD
  • Poor recognition of people
• Progressive Supranuclear palsy:
  • Postural instability
  • Vertical Supranuclear ophthalmoparesis
  • Very similar to multiple system atrophy, Parkinson’s
  • Axial rigidity
• Cortico-basal degeneration:
  • Asymmetric ideomotor apraxia
  • Alien limb phenomenon
  • Visual, sensory hemineglect
  • Myoclonus
  • Non-fluent aphasia
  • Extrapyramidal dysfunction
  • Repeated falls, balance problems
  • Syncope
  • Transient loss of consciousness
  • Neuroleptic sensitivity
  • Rapid eye movement sleep disorder
  • Systematised Delusions
  • Restless Leg Syndrome
  • Autonomic dysfunction- constipation, orthostatic hypotension, urinary incontinence
  • Speech and swallowing problems
• Behavioural problems:
  • Anger, agitation
  • Depression, Anxiety
  • Apathy
  • Excess daytime sleeping
  • Problems following instructions, handling money

Differential Diagnosis

• Very similar to Alzheimer’s dementia. Basic screening for memory problems

Evaluation

• Very similar to Alzheimer’s dementia. Basic screening for memory problems
• Most patients with FTD have normal neurological examination findings. However, frontal lobe dysfunction may have these various reflexes positive- glabellar, sucking, Rooting reflexes, etc
• Neuroimaging- CT, MRI, PET, SPECT, DAT SCAN 

Management

1. There is no specific treatment as such. These treatment options can provide symptomatic treatment. 
2. It is pertinent to get the diagnosis accurately so the right symptomatic treatment and support can be offered. Hence, the importance of detailed collateral history and investigations.
3. Non-pharmacological treatment should be used in the first instance.
4. It is symptomatic management as in other dementias. There is not much benefit to giving acetylcholinesterase inhibitors.

Prognosis

People with a diagnosis live for less than 5 years or so approximately following the diagnosis. 

References

• Bocchetta, M. and Rohrer, J.D. (2020). Frontotemporal dementia. Oxford Textbook of Old Age Psychiatry, [online] pp.513–526. doi:https://doi.org/10.1093/med/9780198807292.003.0033.
• Snowden, J.S., Neary, D. and Mann, D.M.A. (2002). Frontotemporal dementia. The British Journal of Psychiatry, [online] 180(2), pp.140–143. doi:https://doi.org/10.1192/bjp.180.2.140.
• Sivasathiaseelan, H., Marshall, C., Agustus, J., Benhamou, E., Bond, R., van Leeuwen, J., Hardy, C., Rohrer, J. and Warren, J. (2019). Frontotemporal Dementia: A Clinical Review. Seminars in Neurology, 39(02), pp.251–263. doi:https://doi.org/10.1055/s-0039-1683379.
• Dementia UK. (n.d.). Types of dementia. [online] Available at: https://www.dementiauk.org/about-dementia/types-of-dementia/?msclkid=df566113a1b61be45a3902e752c01159 [Accessed 21 Feb. 2023].
• Warren, J.D., Rohrer, J.D. and Rossor, M.N. (2013). Frontotemporal dementia. BMJ, [online] 347(aug12 3), pp.f4827–f4827. doi:https://doi.org/10.1136/bmj.f4827.
• bestpractice.bmj.com. (n.d.). Frontotemporal dementia – Symptoms, diagnosis and treatment | BMJ Best Practice. [online] Available at: https://bestpractice.bmj.com/topics/en-gb/968.