Cerebellar Transcranial Direct Current Stimulation and Aphasia Treatment

Recruiting

Phase N/A Results N/A

Trial Description

People with post-stroke aphasia are left with some degree of chronic deficit for which current rehabilitative treatments are variably effective. This study investigates the behavioral and neural effects of multiple consecutive cerebellar tDCS sessions coupled with computerized naming therapy in stroke survivors with aphasia.

Detailed Description

The investigators will study the effect of right cerebellar transcranial direct current stimulation (tDCS) stimulation during language therapy for naming in individuals with chronic aphasia (>6 months post stroke). Naming difficulties are a persistent and common symptom in aphasia after left-hemisphere (LH) stroke. Although the interventions to improve naming can have benefits, a massive number of treatment sessions is usually required to show gains, particularly in individuals with chronic, large LH stroke. tDCS is a promising adjunct to traditional language therapy. tDCS is a safe, non-invasive, non-painful electrical stimulation of the brain which modulates cortical excitability by application of weak electrical currents in the form of direct current brain polarization. It is usually administered via saline-soaked surface sponge electrodes attached to the scalp and connected to a direct current stimulator with low intensities. Prior investigators have mainly focused on the role of LH in language recovery, wherein the electrode is placed in the left frontal or temporal region. However, in individuals with large lesions involving key language areas like the frontal and temporal cortex, it may be difficult to find viable tissue to stimulate in the LH. This study uses a novel electrode placement for chronic stroke patients with aphasia with large LH lesions. Targeting the intact right cerebellum allows for the possibility of identifying a single target that can be used across groups of people with aphasia with varying lesion sites and size in the LH. Evidence from functional neuroimaging and clinical studies indicate that the right cerebellum is important for both language and cognitive functions.
The investigators will utilize a randomized, double-blind, sham controlled, within-subject crossover trial design. A random subset (half) of participants will be assigned to the "anode" group (Group Anode) and other half will be assigned to the 'cathode' group (Group Cathode). Participants will take part in 2 intervention periods of 15 computerized naming training sessions (3-5 sessions per week), with either tDCS + naming therapy or sham+ naming therapy, separated by 2 months. Detailed language evaluation will take place before, immediately after, 2 weeks and 2 months post-intervention for each condition. The investigators will test the hypothesis that anodal tDCS or cathodal tDCS over the cerebellum and computerized naming therapy is associated with greater gains in accuracy in naming pictures, compared to sham combined with the same computerized naming therapy.

Conditions

Interventions

  • Sham Device
    Intervention Desc: 2 mA of Anodal tDCS or Cathodal tDCS is induced between two 5cm X 5cn saline soaked sponges where one sponge (anode in group Anode and cathode in group Cathode) is placed on the right cerebellum. Ramping up of the current to 2 mA occurs over 15-30 seconds to allow participants to habituate to the tingling sensation. Then, the current will be ramped back down to 0 mA in the sham condition. Termination of the stimulation after the ramping up process is generally undetectable, and the brief duration of stimulation yields no functional effects.
    ARM 1: Kind: Experimental
    Label: Sham plus computerized naming therapy
    Description: Sham tDCS plus computerized naming treatment for 15 sessions (20 minutes per each 45 minute treatment session) over the course of 3-5 weeks. Current will be administered in the in a ramp like fashion for 15-30 seconds but then the current is gradually decreased and drop to 0 mA. Language therapy will be a computer delivered naming +picture matching task.
  • Anodal or Cathodal tDCS Device
    Intervention Desc: 2 mA or Anodal or Cathodal tDCS stimulation is induced between 5cm X5 cm saline soaked sponges where one sponge (anode in group anode or cathode in group cathode) is placed on the right cerebellum. The stimulation will be delivered at an intensity of 2 mA in a ramp-like fashion for a maximum of 20 minutes.
    ARM 1: Kind: Experimental
    Label: tDCS plus computerized naming therapy
    Description: Anodal or cathodal tDCS, 2 milliamps (mA) plus computerized naming treatment for 15 sessions (20 minutes per each 45 minute treatment session) over the course of 3-5 weeks.The electrical current will be administered to the right cerebellum. The stimulation will be delivered at an intensity of 2 mA for a maximum of 20 minutes. Language therapy will be a computer delivered naming +picture matching task.
  • Computerized naming therapy Behavioral
    Intervention Desc: Computer delivered naming treatment requires matching (heard and seen being produced by the speaker) with pictures depicting common objects. It is run on a laptop computer with headphones and 2 large response buttons. During treatment, a picture appears on the laptop screen for 2 seconds. Then, a video of the speaker's face below the nose is presented on the screen saying a word that either matches or does not match the picture. The participant is instructed to press a green response button if the word matches the picture and press the red button if the word does not match the picture.
    ARM 1: Kind: Experimental
    Label: tDCS plus computerized naming therapy
    Description: Anodal or cathodal tDCS, 2 milliamps (mA) plus computerized naming treatment for 15 sessions (20 minutes per each 45 minute treatment session) over the course of 3-5 weeks.The electrical current will be administered to the right cerebellum. The stimulation will be delivered at an intensity of 2 mA for a maximum of 20 minutes. Language therapy will be a computer delivered naming +picture matching task.
    ARM 2: Kind: Experimental
    Label: Sham plus computerized naming therapy
    Description: Sham tDCS plus computerized naming treatment for 15 sessions (20 minutes per each 45 minute treatment session) over the course of 3-5 weeks. Current will be administered in the in a ramp like fashion for 15-30 seconds but then the current is gradually decreased and drop to 0 mA. Language therapy will be a computer delivered naming +picture matching task.

Trial Design

  • Allocation: Randomized
  • Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
  • Purpose: Treatment
  • Endpoint: Efficacy Study
  • Intervention: Crossover Assignment

Outcomes

Type Measure Time Frame Safety Issue
Primary Change in accuracy of naming untrained pictures (Philadelphia Naming Test:PNT) pre- to post-treatment. Before and after 15 sessions (3-5 sessions per week; up to 5 weeks) of treatment. No
Secondary Change in accuracy of naming untrained pictures (PNT) pre- treatment to 2 weeks post treatment. The PNT will be administered at pre-treatment and at 2 weeks post treatment (tDCS and sham) No
Secondary Change in accuracy of naming untrained pictures (PNT) pre- treatment to 2 months post treatment The PNT will be administered at pre-treatment and at 2 months post treatment (tDCS and sham) No
Secondary Change in functional communication skills pre- treatment to post treatment. Before and after 15 sessions of treatment (tDCS and sham) No
Secondary Change in functional communication skills pre- treatment to 2 weeks post-treatment. Pre- treatment and at 2 weeks post treatment (tDCS and sham) No
Secondary Change in functional communication skills pre- treatment to 2 months post treatment. Pre- treatment and at 2 months post treatment (tDCS and sham) No
Secondary Change in lexical features of picture description pre- treatment to post treatment. Before and after 15 sessions of treatment (tDCS and sham) No
Secondary Change in lexical features of picture description pre- treatment to pre- treatment to 2 weeks post-treatment. Pre- treatment and at 2 weeks post treatment (tDCS and sham) No
Secondary Change in lexical features of picture description pre- treatment to 2 months post treatment. Pre- treatment and at 2 months post treatment (tDCS and sham) No

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