Transition of distinctive symptoms of semantic dementia during longitudinal clinical observation

Background/Aims: The aim of this study is to examine the clinical symptoms in a number of semantic dementia (SD) patients and to reveal the longitudinal progression and clinical course of these distinctive symptoms of SD. Methods: 19 consecutive SD patients were examined. Symptoms were classified into 23 distinct categories: behavioral symptoms, language and cognitive symptoms and symptoms concerning the impairment of activities of daily living (ADL). We divided patients into two subgroups, left- and right-dominant SD, and compared the onset of each symptom. Results: Language impairments occurred as the initial symptom in 16 cases. At the first examination, all cases showed both anomia and impairment of word comprehension. By around 3 years after onset, almost all language impairments were observed. Approximately 3–5 years after onset, prosopagnosia and behavioral symptoms appeared. Around the period when the loss of the language faculty and apathy became remarkable, impairment of ADL appeared. Patients spent all day in bed at this stage. Moreover, prosopagnosia appeared significantly earlier in right-dominant SD. Conclusion: Our findings clarify the progression of distinctive symptoms of SD patients. It is necessary to create a treatment strategy for SD patients with such a disease-specific course of SD.