History and exam
Key diagnostic factors
common
coarsening of personality, social behaviour, and habits
Predominance at presentation of coarsening of personality as manifested by characteristics such as disregard for social conventions, slovenly appearance, impatience and irritability, argumentativeness, lewd and tactless remarks, child-like and impulsive actions, loss of empathy and concern for others, compulsions, and rigid adherence to routines.
Changes in personality, habits, and activity generally precede the development of memory impairment, disorientation, or apraxias.
Poor emotional processing is detectable in patients with frontotemporal dementia (FTD), and is an important clinical feature in behavioural variant FTD and semantic dementia.[99]
progressive loss of language fluency or comprehension
Characteristic of the primary progressive subtype of frontotemporal dementia. Changes in language generally precede the development of memory impairment, disorientation, or apraxias.
development of memory impairment, disorientation, or apraxias
Generally preceded by changes in personality, language, habits, and activity.
progressive self-neglect and abandonment of work, activities, and social contacts
Generally presents with a history of progressive self-neglect and abandonment of work, activities, and social contacts.
Other diagnostic factors
common
early age at onset
Onset of progressive cognitive and behavioural decline in mid-life or earlier. The average age of onset is between 45 and 65 years, but there have been documented cases in patients below 30 years and in older people.[25] Prevalence peaks in the seventh decade.[1][4] In one systematic review, frontotemporal dementia accounted for an average of 2.7% of all dementia cases among prevalence studies that included people 65 years and older, compared with 10.2% in studies restricted to those under 65 years.[24]
family history of frontotemporal dementia (FTD)
Between 10% and 30% of cases probably have an autosomal dominant transmission. A family history of FTD is present for 25-50% of patients with autosomal dominant inheritance with mutations in several genes. The behavioural forms of FTD are the most heritable. Known mutations in the MAPT, GRN, and C9orf72 genes each account for between 5% and 10% of all FTDs.[35]
altered eating habits
Altered eating habits may include fads and binge eating disorder.
Patients frequently exhibit altered food preferences, commonly craving sweet foods or carbohydrates, or expressing rigid preferences for particular foods.[134]
inattentiveness, puerile preoccupations, economy of effort, impulsive responding, and compulsive behaviours
These are often observed during cognitive tests and may account for low test scores. The most commonly observed repetitive behaviours among patients with behavioural variant frontotemporal dementia in one study were stereotypies of speech (35.5%), simple repetitive movements (15.2-18.6%), hoarding and collecting (16.9%), and excessive or unnecessary trips to the bathroom (13.5%).[135]
uncommon
signs of amyotrophic lateral sclerosis (ALS)
Frontotemporal dementia may be associated with ALS, the signs of which include progressive asymmetrical weakness of spinal or bulbar muscles and muscle wasting.
parkinsonian symptoms
Symptoms include tremor at rest, hypophonia, slowness of movement, narrowed range of facial expression, stooped posture, unsteadiness of gait (which is also associated with frontotemporal dementia [FTD], and suggestive of FTD with parkinsonism), corticobasal syndrome, and progressive supranuclear palsy.
fasciculations, atrophy, hyper-reflexia, and other signs of motor neuron disease
Patients less commonly manifest signs of motor neuron disease.
glabellar, snout, sucking, rooting, or grasp reflex
Most patients have a normal neurological examination in the early stages, or may have subtle signs suggestive of frontal lobe dysfunction.
loss of bladder and bowel control
Usually occur at advanced stage of the disease, although some men present with urinary urgency and incontinence.
Risk factors
strong
mutations in MAPT gene
Numerous mutations in the MAPT gene have been described.[35] These autosomal dominant mutations typically result in frontotemporal dementia (FTD) with parkinsonism phenotype (FTD with parkinsonism, corticobasal degeneration, and progressive supranuclear palsy). Specific mutations give rise to various different phenotypes and pathological types.[59]
mutations in GRN gene
Numerous mutations in the GRN gene have been described.[35] These autosomal dominant mutations typically result in a behavioural frontotemporal dementia (FTD) phenotype that may be associated with marked impairments of semantic knowledge (FTD, semantic dementia).
mutations in C9orf72 gene
Numerous mutations in the C9orf72 gene have been described.[35] These autosomal dominant mutations are typically associated with behavioural variant frontotemporal dementia (FTD), and there is also an association with FTD with motor neuron features.
other mutations
Other causative gene mutations involve TBK1, TARDBP, VCP-1, FUS, CHMP2B, SQSTM1, CHCHD10, OPTN, TUBA4A, CCNF, TIA1, CYLD, ABCA7, CTSF, and UBQLN2 genes.[60]
weak
traumatic brain injury
Frontotemporal dementia (FTD) is more common in people who have had a traumatic brain injury (TBI) than in those who have not. It is also not known whether head trauma influences age at onset of dementia in patients who have a MAPT or GRN mutation.[45][46][47] TBI with loss of consciousness occurring more than 1 year before diagnosis was associated with an earlier age of symptom onset and diagnosis in patients with behavioural variant FTD.[61] It is not known whether TBI influences age at onset of FTD associated with a gene mutation.
post-traumatic stress disorder (PTSD)
All-cause dementia is more common in people who have had post-traumatic stress disorder than those who have not.[48] A prospective and retrospective Italian study found that patients with a history of PTSD who developed dementia most frequently developed semantic frontotemporal dementia.[49] The mechanism behind the association is not known.
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