Frontotemporal dementia with motor neuron disease

What it is

From: Orphanet

Frontotemporal dementia with motor neuron disease (FTD-MND) is a type of frontotemporal lobar degeneration characterized by the insidious onset (between the ages of 38-78 years) of dementia-associated psychiatric symptoms (e.g. personality changes, uninhibited behavior, irritability, aggressiveness), memory difficulties, global intellectual impairment, emotional disorders and transcortical motor aphasia that eventually leads to mutism, in addition to the manifestations of motor neuron disease such as neurogenic muscular wasting (similar to what is seen in amyotrophic lateral sclerosis). The disease is progressive, with death occurring 2-5 years after onset.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Abnormal lower motor neuron morphology · Very frequent (99-80%)

Any structural anomaly of the lower motor neuron.

Abnormal upper motor neuron morphology · Very frequent (99-80%)

Any structural anomaly that affects the upper motor neuron.

Frontotemporal dementia · Very frequent (99-80%)

A dementia associated with degeneration of the frontotemporal lobe and clinically associated with personality and behavioral changes such as disinhibition, apathy, and lack of insight. The hallmark feature of frontotemporal dementia is the presentation with focal syndromes such as progressive language dysfunction, or aphasia, or behavioral changes characteristic of frontal lobe disorders.

Abnormality of extrapyramidal motor function · Frequent (79-30%)

A neurological condition related to lesions of the basal ganglia leading to typical abnormalities including akinesia (inability to initiate changes in activity and perform volitional movements rapidly and easily), muscular rigidity (continuous contraction of muscles with constant resistance to passive movement), chorea (widespread arrhythmic movements of a forcible, rapid, jerky, and restless nature), athetosis (inability to sustain the muscles of the fingers, toes, or other group of muscles in a fixed position), and akathisia (inability to remain motionless).

Apathy · Frequent (79-30%)

Apathy is a quantitative reduction of interest, motivation and the initiation and persistence of goal-directed behavior, where often the accompanying emotions, thoughts, and social interactions are also diminished. The individual is typically non-reactive to provocations, positive or negative, and appears to not care. Distinguished from lethargy which involves lack of physical or mental energy.

Apraxia · Frequent (79-30%)

A defect in the understanding of complex motor commands and in the execution of certain learned movements, i.e., deficits in the cognitive components of learned movements.

Atypical behavior · Frequent (79-30%)

Atypical behavior is an abnormality in a person's actions that can be controlled or modulated by the will of the individual. While abnormal behaviors can be difficult to control, they are distinct from other abnormal actions that cannot be affected by the individual's will.

Degeneration of the lateral corticospinal tracts · Frequent (79-30%)

Deterioration of the tissues of the lateral corticospinal tracts.

Depression · Frequent (79-30%)

Frequently experiencing feelings of being down, miserable, and/or hopeless; struggling to recover from these moods; having a pessimistic outlook on the future; feeling a pervasive sense of shame; having a low self-worth; experiencing thoughts of suicide and engaging in suicidal behavior.

Distal muscle weakness · Frequent (79-30%)

Reduced strength of the musculature of the distal extremities.

Dysarthria · Frequent (79-30%)

Dysarthric speech is a general description referring to a neurological speech disorder characterized by poor articulation. Depending on the involved neurological structures, dysarthria may be further classified as spastic, flaccid, ataxic, hyperkinetic and hypokinetic, or mixed.

Dyscalculia · Frequent (79-30%)

A specific learning disability involving mathematics and arithmetic.

Dysphagia · Frequent (79-30%)

Difficulty in swallowing.

Generalized amyotrophy · Frequent (79-30%)

Generalized (diffuse, unlocalized) amyotrophy (muscle atrophy) affecting multiple muscles.

Other findings in the same source

From: Orphanet

Additional reported features include Gliosis (Frequent (79-30%)); Hallucinations (Frequent (79-30%)); Paraparesis (Frequent (79-30%)); Parkinsonism (Frequent (79-30%)); Proximal muscle weakness (Frequent (79-30%)); Tetraparesis (Frequent (79-30%)); Weakness due to upper motor neuron dysfunction (Frequent (79-30%)); Neuronal loss in the cerebral cortex (Frequent (79-30%)); Progressive cerebellar ataxia (Frequent (79-30%)); Abnormal mitochondrial morphology (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Adult

Inheritance in the source

From: Orphanet

Autosomal dominant

Understanding the inheritance label

From: MedlinePlus Genetics

An autosomal dominant pattern means that one altered copy of a relevant gene can be sufficient for the condition. Some affected people inherit the change; others have a new change without an affected parent. The precise finding, family history and condition determine what this means for relatives.

Which doctor should you see?

The suggested department for discussing Frontotemporal dementia with motor neuron disease is Neurology, with a neurologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which nervous-system findings help explain the symptoms?
• Would an assessment of walking, communication or daily function be helpful?
• Are rehabilitation or other specialist services relevant?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Frontotemporal dementia with motor neuron disease. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.