____________________________________________________________________ Frontotemporal Dementia
Semantic Variant PPA Semantic variant PPA, also referred to as semantic dementia, represents about 20% of FTD cases [13]. Semantic variant PPA involves the loss of understanding of the meaning of words and objects. Speech is still fluent and grammatically correct, but people with svPPA have a declining ability to comprehend the meaning of words (especially nouns) or to recognize familiar objects or faces. For example, a person with svPPA who is very familiar with vegetables might read a menu and ask: “What is broccoli?” If shown a picture of a carrot, the patient may not be able to name it and may not recognize the word when told. There are progressive word-finding problems, reading and spelling skills decline, and retrieving names becomes difficult. Later in the disease, people with svPPA may develop behavioral changes similar to those seen in patients with bvFTD. Logopenic Variant PPA Logopenic variant PPA is characterized by difficulty retrieving words, resulting in slow speech with frequent pauses. These patients may also have trouble repeating long phrases and understanding complex sentences. Eventually, people with lvPPA may become mute. Reading and writing skills are initially preserved, but these decline as the disease progresses. People with lvPPA have word-finding problems similar to people with AD and are often found to have AD pathology at autopsy [8]. For all patients with suspected language presentations of FTD, it is important to consider the role of culture and preferred language. FTD OVERLAP WITH MOVEMENT DISORDERS Progressive Supranuclear Palsy PSP is a neurodegenerative condition characterized by prob- lems with gait and balance, causing postural instability, falls, and difficulty with eye movement coordination. The patho- physiology of PSP shows a loss of cells in the basal ganglia, substantia nigra, subthalamus, and brainstem, and affected neurons have inclusions composed of abnormal tau protein. There are similarities between PSP and Parkinson disease, including bradykinesia, rigidity, masked face, dysarthria, dysphagia, apathy, and depression. Some people with PSP develop behavioral problems, but these are often milder than those seen in other types of FTD. Some people with PSP may develop progressive memory and language problems, and there may be a decline in executive function. Corticobasal Syndrome CBS is a neurodegenerative condition that may initially present with movement problems, dementia, or both. In CBS, there is atrophy in multiple areas of the brain, including the frontopa- rietal regions, basal ganglia, and cerebral peduncles. Neuronal inclusions are usually composed of abnormal tau protein. Signs of CBS typically begin with decreased movement on one side of the body, muscle rigidity, and tremor. A hand, arm, or leg on the affected side may demonstrate apraxia (i.e., inability to make the limb follow commands). Patients may describe the
affected limb as not feeling like a part of their body, a sensation referred to as “alien limb syndrome.” Symptoms may become bilateral as the disease progresses. People with CBS may also experience personality changes, executive dysfunction, and language problems as the disease progresses. FTD with Motor Neuron Disease Approximately 30% of people with FTD also develop problems with motor neurons that control voluntary movement [3]. This is referred to as FTD with motor neuron disease (FTD/MND) or FTD with amyotrophic lateral sclerosis (FTD/ALS). Patho- logically, in addition to frontal and temporal lobe atrophy, there is also atrophy in the motor regions of the cortex and loss of motor neurons in the brain stem and spinal cord. In FTD/ MND, damaged neurons usually have abnormal inclusions composed of the protein TDP-43. Patients may present with behavior or language problems, but then additionally develop muscle problems, including weakness, stiffness, twitches, cramps, and/or atrophy. Muscle problems can affect arms, legs, face, mouth, and tongue, causing patients to experience clumsiness, dysphagia, dysarthria, and hyper-reflexia. An esti- mated 50% of patients with MND or ALS go on to develop behavioral and executive dysfunction symptoms of FTD as their disease progresses [3]. CLINICAL DIAGNOSIS OF FTD The diagnosis of FTD can be challenging because of the wide range of symptoms, the relatively early age of onset, and the slow progression. There is no single test to diagnose FTD, and it may be initially misdiagnosed as a psychiatric disorder (e.g., depression, schizophrenia), AD, Parkinson disease, or vascular dementia. Accurate diagnosis of FTD is important because some of the medications used to treat these other diseases may be detrimental to patients with FTD. Patients with suspected FTD are often referred to neurologists or neuropsychologists with special expertise in FTD and related neurodegenerative disorders for a comprehensive evaluation. The clinical diagnosis of FTD is based on the clinical history, family history, neurologic examination, neuropsychologic evaluation, and neuroimaging. Other tests may also be per- formed for differential diagnosis. The diagnostic process may take time, and the diagnosis may change as more tests are done or as new symptoms appear. The clinical history is obtained from the patient and his/her family or friends. It is important that family or friends provide information regarding symptoms, as patients are often unaware of their behavior changes. The family history should focus on whether any other relatives have had a neurodegenerative disease. Any cases of dementia, language problems, or movement disorders should be noted, along with specific information about symptoms, diagnosis, age of onset, course of disease, age at death, and autopsy find- ings. Such background information may be valuable for both diagnosis and understanding genetic risk.
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MDRI2026
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