tDCS in Primary Progressive Aphasia

tDCS Intervention in PPA

About PPA

 

Primary progressive aphasia (PPA) is a common type of neurodegenerative disease that affects first and foremost language abilities. In it's early stages it is called Mild Cognitive Impairment (MCI), which is characterized as a slowly progressive decline in a single domain of cognition (e.g. language) not attributable to motor or sensory loss, without impediment of social or occupational function (Petersen, 2003). MCI can be an early sign of neurodegenerative disease, or can be due to normal aging. When language is the prominent affected domain in MCI, the person may later meet criteria for PPA or may progress to the clinical syndrome of Alzheimer’s dementia. Spelling, naming, and working memory (i.e. repetition) are among the language abilities affected early in the course of PPA, and different variants of Primary Progressive Aphasia (PPA) have distinct deficits in these domains (Sepelyak et al., 2010, Budd et al.2010). Naming (word retrieval) and spelling can also be among the earliest functions impaired in MCI when language is the prominent affected domain. Currently there is no available proven treatment for these individuals. 

 

Variants of PPA include: 

  • Non-fluent/Agrammatic 

  • Logopenic

  • Semantic

  • Unclassifiable

 

 

tDCS Intervention

 

Transcranial Direct Current Stimulation (tDCS) is a relatively new, safe, non-invasive, non-painful electrical stimulation of the brain that has resulted in improved language and cognitive abilities in stroke and dementia (AD) when administered during traditional behavioral (language) therapy (Baker et al., 2010; Boggio et al., 2009; Ferrucci et al., 2008; Floel et al., 2008; Monti et al., 2008; Schlaug et al., 2008) tDCS alters neuropeptide concentrations at the sites of stimulation, which is particularly important because individuals with PPA have a specific neuropeptide signature. It has been shown that anodal tDCS can enhance language and motor performance, visuo-motor learning, and recognition memory or working memory. 

 

 

Our Research

 

We are exploring whether anodal tDCS when administered in combination with spelling, naming, or working memory therapy can improve language performance of PPA and MCI participants at least in the short term more than behavioral therapy alone. We are also investigating whether and how tDCS alters the neuropeptide signature in participants with PPA and MCI. We use proton magnetic resonance spectroscopy (1H-MRS) to monitor neuropeptide concentrations at the areas of stimulation. We hypothesize that tDCS will stabilize the decline of specific neuropeptides, but only in those areas of the brain where tDCS effectively results in more efficient gains in language compared to language therapy alone (with sham tDCS).

 

Study results may help optimize future intervention in individuals with PPA and MCI by providing treatment alternatives in a neurodegenerative condition with no proven effective treatment. A better understanding of the therapeutic and neuromodulatory effects of tDCS in PPA and MCI will offer insight into ways of impeding neurodegeneration that may improve quality of life for individuals with PPA and MCI and may provide insights into the mechanisms of this treatment for augmenting therapy for stroke as well. 

 

 

More Information About Our Clinical Trial

 

Visit our clinicaltrials.gov website to find a detailed description of this research project.

 

 

References 

  • Baker JM, Rorden C, Fridriksson J. Using transcranial direct-current stimulation to treat stroke participants with aphasia. Stroke. 2010; 41:1229-1236. (Abstract)

  •  Boggio PS, Khoury LP, Martins DC, Martins OE, de Macedo EC, Fregni F. Temporal cortex direct current stimulation enhances performance on a visual recognition memory task in Alzheimer disease. J Neurol Neurosurg Psychiatry. 2009;80: 444-447. (Abstract)

  • Budd M, Kortte K, Cloutman L, Newhart M, Gottesman RF.,Davis C, Heidler-Gary J, Seay MW. Hillis AE. The nature of naming errors in primary progressive aphasia versus acute post-stroke aphasia. Neuropsychology 2010; 24: 581-589. (Abstract)

  • Ferrucci R, Mameli F, Guidi I, Mrakic-Sposta S, Vergari M, Marceglia S, Cogiamanian F, Barbieri S, Scarpini E, Priori A. Transcranial direct current stimulation improves recognition memory in Alzheimer disease. Neurology. 2008;71: 493-8. (Abstract)

  • Floel A, Rosser N, Michka O, Knecht S, Breitenstein C. Noninvasive brain stimulation improves language learning. J Cogn Neurosci. 2008; 20: 1415-1422. (Abstract)

  • Monti A, Cogiamanian F, Marceglia S, Ferrucci R, Mameli F, Mrakic-Sposta S, Vergari M, Zago S, Priori A. Improved naming after transcranial direct current stimulation in aphasia. J Neurol Neurosurg Psychiatry. 2008 Apr;79(4):451-3. Epub 2007 Dec 20. (Abstract)

  • Petersen RC. Conceptual overview. In: Petersen RC. Mild Cognitive Impairment: Aging to Alzheimer's Disease. 1-14. New York, NY: Oxford University Press, Inc; 2003. (Abstract)

  • Schlaug G, Renga V, Nair D. Transcranial direct current stimulation in stroke recovery. Arch Neurol. 2008; 65:1571-1576. (Abstract)

  • Sepelyak K, Crinion J, Molitoris J, Epstein-Peterson Z, Bann M, Davis C, Newhart M, Heidler-Gary J, Tsapkini K, Hillis AE. Patterns of breakdown in spelling in primary progressive aphasia. Cortex. 2011; 47: 342-52. (Abstract)

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