Volume 7 Issue 9 September, 2017
Frontotemporal dementia is a progressive neurodegenerative disorder and is the second most common cause of early onset dementia (before age 65), second only to Alzheimer’s dementia. The estimated prevalence of FTD is highest in the 45 to 64 year age group and ranges from 15 to 22 per 100,000. It classically affects adults in their fifties to sixties, although cases have been reported in patients from 30 years to more than 90 years of age. FTD affects both genders in roughly equally. The term FTD is typically used to refer to one of the several clinical subtypes including behavioral variant of FTD, Semantic variant primary progressive aphasia (PPA), non fluent agrammatic variant and FTD associated with motor neuron disease. FTD related disorders include two tau-associated neuro-degenerative diseases, corticobasal syndrome and progressive supra nuclear palsy which can present with frontal lobe dysfunction. Behavioral variant of FTD is gradual in onset and progresses with change in behavior including disinhibition, loss of empathy, apathy, hyperorality and perseverative or compulsive behavior. Patient with FTD demonstrate deficits in executive function tasks with relative sparing in memory and visuospatial domains. They may also exhibit psychotic features including visual or auditory hallucinations bizarre or somatic delusions.
The hallmark symptom of semantic variant of primary progressive aphasia is the loss of word meaning. Atrophy of the dominant anterior temporal lobe is the characteristic finding in semantic variant of primary progressive aphasia. Approximately 20 percent of patients with progressive supranuclear palsy first present with behavioral changes or progressive language deficits. Patients with CBD may first present with behavioral changes, executive function deficits or language deficits.
FTD is found in approximately 30 percent of patients diagnosed with amyotrophic lateral sclerosis.
40 percent of FTD are associated with autosomal dominant pattern of inheritance, remaining cases are considered sporadic. Genetic mutation may be found in approximately 6 percent of patients with no family history of FTD. Abnormal accumulation of tau or TDP-43 is found in pathologically confirmed cases of FTD.
At present there are no validated bio markers that can reliably distinguish patients with FTD from controls or other types of dementia.
Although currently no medications will prevent slow decline or cure FTD, many of the symptoms can be treated. Both pharmacological and behavioral interventions are available for symptomatic benefit of specific cognitive and behavioral features.
SSRI’S are often useful treating a wide range of behavioral symptoms in FTD including apathy, depression, agitation, anxiety and obsessive compulsive behaviors.
Choline esterase inhibitors may help temporarily stabilize cognitive symptoms including aphasia symptoms, apathy and executive functioning.
Dr. Veda N. Shetageri, Associate Professor, Dept. of Psychiatry, MVJMC & RH, Hoskote, Bengaluru
