Abstract
Recent epidemiological studies on dementia show a constantly higher prevalence of the disease, with an estimated threefold increase in the number of patients by 2050. Taking these data into account, early and valid diagnosis of dementia is considered necessary, to establish the appropriate treatment and estimate the prognosis of the patient’s course. However, distinguishing Alzheimer’s Disease (AD) and Frontotemporal Demetia (FTD) in patients with moderate to advanced disease remains difficult, due to common clinical expression of cognitive impairment and atypical manifestations occurring in both forms. Therefore, clinical and laboratory findings that contribute, at an early stage, in the differential diagnosis process are considered valuable and should not be overlooked by the treating physician. The widespread use of new biological markers and imaging methods, in recent years, play an increasingly important role in the differential diagnosis process. Disorders of praxis circuit, and ...
Recent epidemiological studies on dementia show a constantly higher prevalence of the disease, with an estimated threefold increase in the number of patients by 2050. Taking these data into account, early and valid diagnosis of dementia is considered necessary, to establish the appropriate treatment and estimate the prognosis of the patient’s course. However, distinguishing Alzheimer’s Disease (AD) and Frontotemporal Demetia (FTD) in patients with moderate to advanced disease remains difficult, due to common clinical expression of cognitive impairment and atypical manifestations occurring in both forms. Therefore, clinical and laboratory findings that contribute, at an early stage, in the differential diagnosis process are considered valuable and should not be overlooked by the treating physician. The widespread use of new biological markers and imaging methods, in recent years, play an increasingly important role in the differential diagnosis process. Disorders of praxis circuit, and more specifically limb apraxia, are features of the clinical picture of patients with AD. Numerous research data emphasize its appearance even in the early stages of the disease, but its frequency and severity do not offer additional information that could be exploited by the clinician. Recent published studies highlight the relatively common occurrence of apraxia in FTD, question its presence as a strong clinical finding in favor of AD, and stress the need for further investigations on the presence or absence of the apractic phenomena that demented patients may experience. In this context, the purpose of this dissertation was to study the three major apractic disturbances (limb apraxia, apraxia of speech and buccofacial apraxia) of patients with FTD and to compare their profile with AD patients in the Greek population.We studied the correlation of apraxia with the clinical diagnosis, the severity of cognitive dysfunction and the duration of the disease. Comparison of its appearance with regional cerebral blood flow (rCBF) in 63 patients with FTD (behavioral variant and primary progressive aphasia) and 22 patients with AD followed. Evaluation of apraxia of speech and buccofacial apraxia was performed utilizing the Apraxia Battery for Adults - 2 (ABA-2), previously adapted to the Greek population, and limb apraxia with the Test for Upper Limb Apraxia (TULIA), which did not require adjustment, additionally to ABA-2. Adenbrooke’s Cognitive Examination - Revised (ACE-R) tool, adapted to the Greek population, was used to assess the severity of cognitive dysfunction in the entire patient sample. Two additional scales, the Frontal Rating Scale (FRS) and Frontal Behavioral Inventory (FBI) were used to confirm the diagnosis and stage disease activity in patients suffering from FTD. Finally, imaging analysis with Single Photon Emission Computed Tomography (SPECT) scan of the brain was used for measuring the rCBF. ABA-2 was initially adapted to the Greek population using the same instrument studied in patients with stroke, with a slight modification of a subtest and the subtraction of two other, in order to provide an easier battery that can also be used as a bed-side test. It proved being equally reliable in distinguishing apractic disturbances between demented patients and healthy population, taking into account age, sex, years of education and disease duration. Validation of TULIA in the Greek population was not considered necessary as the movements ordered to be executed do not depend on factors that may affect the results (age, sex, years of education, linguistic features).We noted that apraxia of speech and ideomotor apraxia are not characteristic of any dementia syndrome, but seem to appear in all patients with AD, bvFTD and PPA, while buccofacial apraxia was more evident in patients with PPA. Ideomotor apraxia will worsen faster in patients with AD and apraxia of speech in those with FTD, when cognitive status deteriorates. Additionally, disease duration did not seem to affect the degree of apraxia. Taking brain pathology as an independent factor of praxis circuit deterioration, we concluded that the left and right parietal lobes play a regulatory role in apraxia appearance in patients with AD, in contrast with the temporal lobes. In the bvFTD and PPA groups no similar role, in the respective areas of interest, was found. Cognitive impairment correlated with apraxia of speech in AD and bvFTD patients, accounting for temporal / parietal and frontal / temporal areas, respectively. Finally, when differentiating AD from bvFTD, the presence of moderate ideomotor apraxia or apraxia of speech could indicate a possible diagnosis of AD or bvFTD, respectively. When comparing AD with PPA groups, only apraxia of speech in moderate degree could serve in directing the diagnosis towards PPA. In our last comparison, which included the FTD spectrum diseases (bvFTD and PPA), the presence of ideomotor apraxia, and more specifically when imitation and pantomime of transitive and intransitive movements were executed, characterized patients with PPA, whereas apraxia of speech and buccofacial apraxia did not seem to be characteristic for neither of diseases.In summary, our study evaluates thoroughly and for the first time the presence of the three most common types of apraxia in Greek patients suffering from FTD and AD and confirms the possibility of using this clinical symptom as a differential tool between these patients. Additionally, we highlighted factors that correlate with apraxia and could predetermine its frequency and severity in each disease. The differences in the individual types of apraxia between patient categories could be a crucial clinical diagnostic criterion and consequently an important factor in the therapeutic approach of these patients (pharmaceutical and non-pharmaceutical).
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