The effect of Subthalamic nucleus deep brain stimulation on verb and noun naming in Turkish-Speaking Parkinson's disease patients.

Parkinson's disease (PD) is associated with an action language deficit. Subthalamic nucleus deep brain stimulation (STN DBS) deteriorates verbal fluency, but may improve verb naming more than nouns in PD. We investigated effects of grammatical class (verb vs noun), action content (action vs non-action) of words and unilateral, bilateral or no stimulation on naming. Nouns were named more accurately and faster by controls and PD participants; however the noun-verb difference was higher for PD participants. Language, executive and visuospatial function deficits in PD accounted for this difference between PD group and controls. Noun-verb difference was accounted by differences in imageability, familiarity and complexity of the stimuli. Non-action words were named more accurately than action words in the overall sample. Stimulation conditions did not have an effect on naming. This study in Turkish-speaking participants show an action language deficit due to underlying cognitive deficits without an STN DBS effect in PD.

A Picture Database for Verbs and Nouns with Different Action Content in Turkish.

In this study we present a picture database of 160 nouns and 160 verbs. All verbs and nouns are divided into two groups as action and non-action words. Age of acquisition, familiarity, imageability, name agreement and complexity norms are reported alongside frequency, word length and morpheme count for each word. Data were collected from 600 native Turkish adults in total. The results show that although several measures have weak correlations with each other, only age of acquisition had moderate downhill relationships with familiarity and frequency with familiarity and frequency having a rather strong positive correlation with each other. The norms and the picture database are available as supplemental materials for use in psycholinguistic studies in Turkish.