Logoclonia, which is the meaningless repetition of a syllable, particularly an end syllable of a word, has been described in patients with dementia for a century. The mechanisms behind logoclonia, however, have yet to be clarified. Among 914 patients with aphasia, five patients presented with logoclonia, all of whom were categorized as having logopenic variant PPA (lvPPA) during the initial stage of their illness and met the clinical criteria for diagnosis of probable Alzheimer's disease. Cognitively, they were all severely impaired when they presented with logoclonia. During the progression from lvPPA to logoclonia in these patients, their naming abilities and phonological output function deteriorated despite their retained speech fluency. Logoclonia might be a characteristic sign of advanced-stage lvPPA. Although logoclonia might be associated with perseveration, deterioration in naming abilities and phonological output function along with retained speech fluency might form the basis for the development of logoclonia.