treating primary progressive aphasia (ppa) using tdcs

Conditions: Primary Progressive Aphasia

Summary: this is a double-blind, sham-controlled, crossover study in which subjects with the non-fluent/agrammatic and semantic variants of primary progressive aphasia (nappa and svppa, respectively) will undergo language testing and structural and functional brain imaging before and after receiving 10 semi-consecutive daily sessions of real or sham transcranial direct current stimulation (tdcs) paired with modified constraint-induced language therapy (mcilt). language testing and brain imaging will be repeated immediately after completion of and up-to 24 weeks following completion of treatment. the investigators will examine changes in language performance induced by tdcs + mcilt compared to sham tdcs + mcilt. the investigators will also use network science to analyze brain imaging (fmri) data to identify network properties associated with baseline ppa severity and tdcs-induced changes in performance. this study will combine knowledge gained from our behavioral, imaging, and network data in order to determine the relative degrees to which these properties predict whether persons with ppa will respond to intervention.

the central framework for the project is a double-blind, sham-controlled, crossover study in which subjects with the non-fluent/agrammatic and semantic variants of primary progressive aphasia (nappa and svppa, respectively) will undergo language testing and structural and functional brain imaging before and after receiving 10 semi-consecutive daily sessions of real or sham transcranial direct current stimulation (tdcs) paired with modified constraint-induced language therapy (mcilt). language testing and brain imaging will be repeated immediately after completion of and up-to 24 weeks following completion of treatment. subjects with nappa and svppa will be randomized to one of two study arms: tdcs+mcilt or sham stimulation+mcilt paired with pre- and post-stimulation imaging and behavioral measures. equal numbers of subjects with nappa and svppa will be randomized to the tdcs + mcilt and sham + mcilt study arms. the study is double-blinded, in that neither the subject nor the study personnel administering tdcs or sham stimulation will know which arm of the study the subject has been randomized into. study coordinators will administer tdcs by entering a pre-determined code that has been programmed into the device by another member of the study team. data will be digitally audio-recorded and analyzed off-line, such that study team members performing data coding and analysis will likewise be blinded to the treatment condition of each subject. subject participation in this protocol will occur during 36 planned visits that will span approximately 12 months. the events of the study visits are described below: visit 1: informed consent and screening visit 2: baseline mri visit 3 \& 4: baseline language assessment visits 5-14: tdcs+mcilt or sham stimulation+mcilt, depending on the study arm to which they had been randomized. visit 15 \& 16: follow-up language assessment follow-up mri visit 17: 6-week follow-up language assessment visit 18 \& 19: 12-week follow-up language assessment 12-week follow-up mri \*\*crossover\*\* visit 20: crossover baseline language assessment visits 21-30: tdcs+mcilt or sham stimulation+mcilt visit 31 \& 32: follow-up language assessment follow-up mri visit 33: 6 week follow-up language assessment visit 34 \& 35: 12-week follow-up language assessment 12-week follow-up mri visit 36: 24 week follow-up language assessment

Eligibility criteria:
inclusion criteria: * presence of aphasia attributable to the semantic variant (svppa) or non- fluent/agrammatic variant (nappa) of primary progressive aphasia. * must be a native english speaker exclusion criteria: * history of seizures or unexplained loss of consciousness * subjects with metallic objects in the face or head other than dental apparatus such as braces, ﬁllings, and implants. * subjects with pacemakers or icds. * subjects with previous craniotomy or any breach in the skull * subjects with a history of other neurological disorder (stroke, tbi, parkinson) * subjects with a history of small vessel disease

Keywords: non-invasive brain stimulation transcranial direct current stimulation (tdcs) speech therapy