Pick’s disease is a complex neurodegenerative disorder characterized by dementia due to damage and shrinkage within the frontal and temporal lobes of the brain. These areas of the brain are responsible for controlling speech and emotion, and as a result, patients with Pick’s disease often have difficulty speaking, understanding vocabulary, and controlling their emotions, especially in social settings. Caregivers of those with Pick’s disease often report changes in behavior, impulsiveness, a lack of socially appropriate behavior, and a tendency towards obsessiveness. Unlike patients who suffer from Alzheimer’s disease, patients with Pick’s disease do not lose short-term memory.
Pick’s disease is a subset of a larger grouping of neurodegenerative disorders termed frontotemporal dementia. Frontotemporal dementias are classified according to their associated shrinkage of the temporal and frontal lobe regions and consist of Pick’s disease, primary progressive aphasia, and semantic dementia. Specifically, Pick’s disease is characterized by the presence of Pick bodies, which are abnormal aggregations of the neuronal protein tau, and Pick cells, which are swollen neuronal cells. Pick bodies and Pick cells result in loss of neuronal connections and cell death within the temporal and frontal lobes, leading to the physical shrinkage of these brain regions.
Characterization of patients with various forms of frontotemporal dementia-associated symptoms were first described in the late 19th and early 20th century by Arnold Pick, a professor of psychiatry in Prague. Pick was described as an intelligent, modest, and principled man who made substantial contributions to the fields of psychiatry and neurology through numerous publications in the German and English languages. Pick studied and reported on the clinical symptoms of a patient named August H., who suffered from severe aphasia (loss of language skills) due to temporal degeneration and was later thought to be the first published case of primary progressive aphasia, and later reported on a patient named Anna H., whose symptoms included behavioral abnormalities and loss of cognitive function that were consistent with frontal dementia. A third report characterized a patient named Anna J., a 75-year old woman with temporal deterioration who exhibited language impairment and loss of conceptual knowledge, such as the appropriate use of everyday household items. Together, these patients formed the basis for Pick’s hypothesis that dementia was the result of localized deterioration of specific brain regions, and not due to generalized loss of brain function.
Classification of Pick’s Disease
Although Arnold Pick’s studies often included autopsy of the brain to study size and/or shrinkage of specific brain regions, his reports did not contain histopathological data at the cellular level. In fact, it was later studies by Alois Alzheimer in 1911 that first identified the protein accumulations and swollen neurons, later known as Pick bodies and Pick cells, that characterized Pick’s disease. Other researchers in the 1920s formally classified Pick’s disease based on clinical and pathologic findings. In the following decades, the term Pick’s disease was used internationally to refer to both the clinical manifestation of dementia associated with frontal or temporal lobe degeneration as well as the pathological presence of Pick bodies. Today, clinicians use the general term frontotemporal dementia and can specifically diagnose the Pick’s disease subtype if Pick bodies are present upon brain scan using magnetic resonance imaging (MRI) or computerized tomography (CT).