Echolalia is the automatic imitative repetition of sounds, words, or phrases in the absence of explicit awareness. The repeated words or phrases are typically odd or used in a non-social manner. These can be words or phrases that the affected individual has heard or invented.

Gliosis is the focal proliferation of glial cells in the central nervous system.

A neurological anomaly with gross overeating associated with an abnormally strong desire or need to eat.

Language impairment is a deficit in comprehension or production of language that includes reduced vocabulary, limited sentence structure, or impairments in written or spoken communication. Language abilities are substantially and quantifiably below age expectations.

Use of the same abnormal action in response to certain triggers or at random. They may be used as a way to regulate one's internal state but must otherwise have no apparent functional purpose.

Apathy is a quantitative reduction of motivation and the initiation and persistence of goal-directed behavior, where the accompanying emotions, thoughts, and social interactions are also suppressed.

Inability to feel positive or negative emotions, feelings of detachment, or reduced emotional responsiveness.

Manifestations of perseverative thoughts are behaviors that do not meet the demands of the situation, are not the product of deliberation, and may unfold despite counter intention.

An abnormal shift in patterns of thinking, acting, or feeling.

Frontotemporal dementia (FTD) refers to a clinical manifestation of the pathologic finding of frontotemporal lobar degeneration (FTLD). FTD, the most common subtype of FTLD, is a behavioral variant characterized by changes in social and personal conduct with loss of volition, executive dysfunction, loss of abstract thought, and decreased speech output. A second clinical subtype of FTLD is 'semantic dementia,' characterized by specific loss of comprehension of language and impaired facial and object recognition. A third clinical subtype of FTLD is 'primary progressive aphasia' (PPA), characterized by a reduction in speech production, speech errors, and word retrieval difficulties resulting in mutism and an inability to communicate. All subtypes have relative preservation of memory, at least in the early stages. FTLD is often associated with parkinsonism or motor neuron disease (MND) resembling amyotrophic lateral sclerosis (ALS; 105400) (reviews by Tolnay and Probst, 2002 and Mackenzie and Rademakers, 2007). Mackenzie et al. (2009, 2010) provided a classification of FTLD subtypes according to the neuropathologic findings (see PATHOGENESIS below). Clinical Variability of Tauopathies Tauopathies comprise a clinically variable group of neurodegenerative diseases characterized neuropathologically by accumulation of abnormal MAPT-positive inclusions in nerve and/or glial cells. In addition to frontotemporal dementia, semantic dementia, and PPA, different clinical syndromes with overlapping features have been described, leading to confusion in the terminology (Tolnay and Probst, 2002). Other terms used historically include parkinsonism and dementia with pallidopontonigral degeneration (PPND) (Wszolek et al., 1992); disinhibition-dementia-parkinsonism-amyotrophy complex (DDPAC) (Lynch et al., 1994); frontotemporal dementia with parkinsonism (FLDEM) (Yamaoka et al., 1996); and multiple system tauopathy with presenile dementia (MSTD) (Spillantini et al., 1997). These disorders are characterized by variable degrees of frontal lobe dementia, parkinsonism, motor neuron disease, and amyotrophy. Other neurodegenerative associated with mutations in the MAPT gene include Pick disease (172700) and progressive supranuclear palsy (PSP; 601104), Inherited neurodegenerative tauopathies linked to chromosome 17 and caused by mutation in the MAPT gene have also been collectively termed 'FTDP17' (Lee et al., 2001). Kertesz (2003) suggested the term 'Pick complex' to represent the overlapping syndromes of FTD, primary progressive aphasia (PPA), corticobasal degeneration (CBD), PSP, and FTD with motor neuron disease. He noted that frontotemporal dementia may also be referred to as 'clinical Pick disease' and that the term 'Pick disease' should be restricted to the pathologic finding of Pick bodies. Genetic Heterogeneity of Frontotemporal Lobar Degeneration Mutations in several different genes can cause frontotemporal dementia and frontotemporal lobar degeneration, with or without motor neuron disease. See FTLD with TDP43 inclusions (607485), caused by mutation in the GRN gene (138945) on chromosome 17q21; FTLALS7 (600795), caused by mutation in the CHMP2B gene (609512) on chromosome 3p11; inclusion body myopathy with Paget disease and FTD (IBMPFD; 167320), caused by mutation in the VCP gene (601023) on chromosome 9p13; ALS6 (608030), caused by mutation in the FUS gene (137070) on 16p11; ALS10 (612069), caused by mutation in the TARDBP gene (605078) on 1p36; and FTDALS1 (105550), caused by mutation in the C9ORF72 gene (614260) on 9p21. In 1 family with FTD, a mutation was identified in the presenilin-1 gene (PSEN1; 104311) on chromosome 14, which is usually associated with a familial form of early-onset Alzheimer disease (AD3; 607822).

Laughing that may be excessive and/or inappropriate in context (e.g., laughing at a funeral while others are crying).

A reduction in goal-directed behavior, that is, motivation, is the determinant of behavior and adaptation that allows individuals to get started, be energized to perform a sustained and directed action.

Reduced ability to control, or a failure to resist a temptation, urge, or impulse. Examples include disregard for social conventions, general impulsivity, and poor risk assessment.

The primitive reflexes are a group of behavioral motor responses which are found in normal early development, are subsequently inhibited, but may be released from inhibition by cerebral, usually frontal, damage. They are thus part of a broader group of reflexes which reflect release phenomena, such as exaggerated stretch reflexes and extensor plantars. They do however involve more complex motor responses than such simple stretch reflexes, and are often a normal feature in the neonate or infant.

Hyperorality is a condition characterized by an excessive preoccupation with oral sensations and behaviors, such as chewing, sucking, biting, swallowing, and excessive mouthing of objects.

A proneness to anger, i.e., a tendency to become easily bothered or annoyed.