Transcranial direct current stimulation in post-stroke aphasia rehabilitation: A systematic review

Treatment of post-stroke aphasia: A narrative review for stroke neurologists

This review is intended to help physicians guide patients to optimal management of post-stroke aphasia. We review literature on post-stroke aphasia treatment, focusing on: (1) when and for whom language therapy is most effective, (2) the variety of approaches that can be effective for different individuals, and (3) the extent to which behavioral therapy might be augmented by non-invasive brain stimulation and/or medications.

Current Approaches to the Treatment of Post-Stroke Aphasia

Aphasia, impairment of language after stroke or other neurological insult, is a common and often devastating condition that affects nearly every social activity and interaction. Behavioral speech and language therapy is the mainstay of treatment, although other interventions have been introduced to augment the effects of the behavioral therapy. In this narrative review, we discuss advances in aphasia therapy in the last 5 years and focus primarily on properly powered, randomized, controlled trials of both behavioral therapies and interventions to augment therapy for post-stroke aphasia. These trials include evaluation of behavioral therapies and computer-delivered language therapies. We also discuss outcome prediction trials as well as interventional trials that have employed noninvasive brain stimulation, or medications to augment language therapy. Supported by evidence from Phase III trials and large meta-analyses, it is now generally accepted that aphasia therapy can improve language processing for many patients. Not all patients respond similarly to aphasia therapy with the most severe patients being the least likely responders. Nevertheless, it is imperative that all patients, regardless of severity, receive aphasia management focused on direct therapy of language deficits, counseling, or both. Emerging evidence from Phase II trials suggests transcranial brain stimulation is a promising method to boost aphasia therapy outcomes.

A systematic review of repetitive transcranial magnetic stimulation in aphasia rehabilitation: Leads for future studies

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive tool that induces neuromodulation in the brain. Several studies have shown that rTMS improves language recovery in patients with post-stroke aphasia.

OBJECTIVE

This systematic review summarizes the role of rTMS in aphasia rehabilitation.

METHODS

We searched MEDLINE via PubMed and Scopus on 30October, 2020, for English articles (1996-2020). Eligible studies involved post-stroke aphasia rehabilitation with rTMS. In some of these studies, rTMS was also combined with speech therapy.

RESULTS

In total, seven meta-analyses and 59studies (23randomized clinical trials) were included in this systematic review. The methods used in these studies were heterogeneous. Only six studies did not find that rTMS had a significant effect on language performance.

CONCLUSIONS

The evidence from the peer-reviewed literature suggests that rTMS is an effective tool in post-stroke aphasia rehabilitation. However, the precise mechanisms that underlie the effects of rTMS and the reorganization of language networks in patients who have had a stroke remain unclear. We discuss these crucial challenges in the context of future studies.

Extended fMRI-Guided Anodal and Cathodal Transcranial Direct Current Stimulation Targeting Perilesional Areas in Post-Stroke Aphasia: A Pilot Randomized Clinical Trial

Transcranial direct current stimulation (tDCS) may enhance speech and language treatment (SLT) for stroke survivors with aphasia; however, to date, there is no standard protocol for the application of tDCS in post-stroke aphasia. We explored the safety and efficacy of fMRI-guided tDCS on functional language and cortical activity when delivered to the lesioned left hemisphere concurrently with SLT across an extended, six-week treatment period. Twelve persons with chronic, nonfluent aphasia following a single left-hemisphere stroke participated in the three-arm (anodal vs. cathodal vs. sham) single-blind, parallel, pilot trial. No serious adverse events occurred during 30 treatment sessions or in the following six weeks. All groups demonstrated functional language gains following intensive treatment; however, active tDCS resulted in greater gains in standardized, probe, and caregiver-reported measures of functional language than sham. Evidence declaring one polarity as superior for inducing language recovery was mixed. However, cathodal stimulation to the lesioned left hemisphere, expected to have a down-regulating effect, resulted in increased areas of cortical activation across both hemispheres, and specifically perilesionally. Generalization of these preliminary findings is limited; however, results are nevertheless compelling that tDCS combined with SLT can be safely applied across extended durations, with the potential to enhance functional language and cortical activation for persons with aphasia.

Effect of Anodic Transcranial Direct Current Stimulation Combined With Speech Language Therapy on Nonfluent Poststroke Aphasia

OBJECTIVES

Transcranial direct current stimulation (tDCS) facilitates or inhibits spontaneous neuronal activity by low-intensity current. In this study, we evaluated the effects of tDCS and sham stimulation combined with speech language therapy (SLT) on nonfluent poststroke aphasia (PSA) patients.

MATERIALS AND METHODS

Patients with PSA were randomly divided into the anode tDCS (A-tDCS) group (n = 8) and sham tDCS (S-tDCS) group (n = 10). The anodes and cathodes were fixed over left inferior gyrus frontalis (L-IFG) and the deltoid muscle of the right shoulder. A-tDCS consisted of 2 mA for 20 min, while S-tDCS current started at 2 mA but automatically decreased to 0 mA after 30 sec. Stimulation was concurrent with 30 min of SLT. Stimulation + SLT sessions occurred five times a week for four weeks. The Western Aphasia Battery (WAB) was given before treatment to obtain the baseline score and once more after all sessions were completed, and the Aphasia Quotient (AQ) was calculated.

RESULTS

After tDCS treatment, the AQ mean(SD) in both groups was significantly higher than before treatment (p < 0.001) and the AQ of the A-tDCS group 72.99 (21.91) was significantly higher than that of the S-tDCS group 46.18 (19.29) (t = 2.760, p < 0.05). Upon further analysis of the WAB subscores, except for comprehension, all other items were significantly higher in the A-tDCS group than in the S-tDCS group (p < 0.05).

CONCLUSION

Our results suggest that left inferior gyrus frontalis anodic transcranial direct current stimulation is an effective adjuvant to conventional speech language therapy for patients with nonfluent PSA.

Machine learning identifies stroke features between species

Identification and localization of ischemic stroke (IS) lesions is routinely performed to confirm diagnosis, assess stroke severity, predict disability and plan rehabilitation strategies using magnetic resonance imaging (MRI). In basic research, stroke lesion segmentation is necessary to study complex peri-infarction tissue changes. Moreover, final stroke volume is a critical outcome evaluated in clinical and preclinical experiments to determine therapy or intervention success. Manual segmentations are performed but they require a specialized skill set, are prone to inter-observer variation, are not entirely objective and are often not supported by histology. The task is even more challenging when dealing with large multi-center datasets, multiple experimenters or large animal cohorts. On the other hand, current automatized segmentation approaches often lack histological validation, are not entirely user independent, are often based on single parameters, or in the case of complex machine learning methods, require vast training datasets and are prone to a lack of model interpretation.

Methods: We induced IS using the middle cerebral artery occlusion model on two rat cohorts. We acquired apparent diffusion coefficient (ADC) and T2-weighted (T2W) images at 24 h and 1-week after IS induction. Subsets of the animals at 24 h and 1-week post IS were evaluated using histology and immunohistochemistry. Using a Gaussian mixture model, we segmented voxel-wise interactions between ADC and T2W parameters at 24 h using one of the rat cohorts. We then used these segmentation results to train a random forest classifier, which we applied to the second rat cohort. The algorithms' stroke segmentations were compared to manual stroke delineations, T2W and ADC thresholding methods and the final stroke segmentation at 1-week. Volume correlations to histology were also performed for every segmentation method. Metrics of success were calculated with respect to the final stroke volume. Finally, the trained random forest classifier was tested on a human dataset with a similar temporal stroke on-set. Manual segmentations, ADC and T2W thresholds were again used to evaluate and perform comparisons with the proposed algorithms' output.

Results: In preclinical rat data our framework significantly outperformed commonly applied automatized thresholding approaches and segmented stroke regions similarly to manual delineation. The framework predicted the localization of final stroke regions in 1-week post-stroke MRI with a median Dice similarity coefficient of 0.86, Matthew's correlation coefficient of 0.80 and false positive rate of 0.04. The predicted stroke volumes also strongly correlated with final histological stroke regions (Pearson correlation = 0.88, P < 0.0001). Lastly, the stroke region characteristics identified by our framework in rats also identified stroke lesions in human brains, largely outperforming thresholding approaches in stroke volume prediction (P<0.01).

Conclusion: Our findings reveal that the segmentation produced by our proposed framework using 24 h MRI rat data strongly correlated with the final stroke volume, denoting a predictive effect. In addition, we show for the first time that the stroke imaging features can be directly translated between species, allowing identification of acute stroke in humans using the model trained on animal data. This discovery reduces the gap between the clinical and preclinical fields, unveiling a novel approach to directly co-analyze clinical and preclinical data. Such methods can provide further biological insights into human stroke and highlight the differences between species in order to help improve the experimental setups and animal models of the disease.

Identifiable Patterns of Trait, State, and Experience in Chronic Stroke Recovery

BACKGROUND

Considerable evidence indicates that the functional connectome of the healthy human brain is highly stable, analogous to a fingerprint.

OBJECTIVE

We investigated the stability of functional connectivity across tasks and sessions in a cohort of individuals with chronic stroke using a supervised machine learning approach.

METHODS

Twelve individuals with chronic stroke underwent functional magnetic resonance imaging (fMRI) seven times over 18 weeks. The middle 6 weeks consisted of intensive aphasia therapy. We collected fMRI data during rest and performance of 2 tasks. We calculated functional connectivity metrics for each imaging run, then applied a support vector machine to classify data on the basis of participant, task, and time point (pre- or posttherapy). Permutation testing established statistical significance.

RESULTS

Whole brain functional connectivity matrices could be classified at levels significantly greater than chance on the basis of participant (87.1% accuracy; P < .0001), task (68.1% accuracy; P = .002), and time point (72.1% accuracy; P = .015). All significant effects were reproduced using only the contralesional right hemisphere; the left hemisphere revealed significant effects for participant and task, but not time point. Resting state data could also be used to classify task-based data according to subject (66.0%; P < .0001). While the strongest posttherapy changes occurred among regions outside putative language networks, connections with traditional language-associated regions were significantly more positively correlated with behavioral outcome measures, and other regions had more negative correlations and intrahemispheric connections.

CONCLUSIONS

Findings suggest the profound importance of considering interindividual variability when interpreting mechanisms of recovery in studies of functional connectivity in stroke.

Transcranial Direct Current Stimulation in the Treatment of Subacute Post-Stroke Thalamic Aphasia

Background

Although many studies have demonstrated the effectiveness of transcranial direct current stimulation (tDCS) in improving speech recovery in post-stroke aphasia, as far as we know patients affected by thalamic aphasia have never been investigated.

Patient and method

A 65-year-old man with severe non-fluent aphasia due to a left thalamic haemorrhagic stroke underwent intensive daily speech therapy combined with tDCS.

Results

The patient showed progressive improvement with almost complete recovery of his speech disorder, behavioural disinhibition and apathy.

Conclusions

Our findings suggest that tDCS with concurrent speech therapy can be useful in patients with subcortical stroke lesions.

LEARNING POINTS

The thalamus has a central role in the development of the higher functions, such as memory, regulation of behaviour and emotions, and language elaboration.Transcranial direct current stimulation (tDCS) applied to the cerebral cortex is a promising tool for improving language recovery in patients with post-stroke aphasia.Combined treatment with tDCS and speech and language therapy (SLT) was effective in a patient with subacute thalamic aphasia, who showed improvement in all aspects of linguistic and behavioural communication.

Funktionserholung nach Schlaganfall und die therapeutische Rolle der nicht-invasiven Hirnstimulation

Im Bereich der non-invasiven Hirnstimulation stellen die transkranielle Magnetstimulation (engl. transcranial magnetic stimulation, TMS) sowie die transkranielle Gleichstromstimulation (engl. transcranial direct current stimulation, tDCS) bis heute die wichtigsten Techniken zur Modulation kortikaler Erregbarkeit dar. Beide Verfahren induzieren Nacheffekte, welche die Zeit der reinen Stimulation überdauern, und ebnen damit den Weg für ihren therapeutischen Einsatz beim Schlaganfall. In diesem Übersichtsartikel diskutieren wir die aktuelle Datenlage TMS- und tDCS-vermittelter Therapien für die häufigsten schlaganfallbedingten Defizite wie Hemiparese, Aphasie und Neglect. Darüber hinaus adressieren wir mögliche Einschränkungen der gegenwärtigen Ansätze und zeigen Ansatzpunkte auf, um Neuromodulation nach Schlaganfall effektiver zu gestalten und damit das Outcome der Patienten zu verbessern.

Brain hothubs and dark functional networks: correlation analysis between amplitude and connectivity for Broca's aphasia

Source localization and functional brain network modeling are methods of identifying critical regions during cognitive tasks. The first activity estimates the relative differences of the signal amplitudes in regions of interest (ROI) and the second activity measures the statistical dependence among signal fluctuations. We hypothesized that the source amplitude–functional connectivity relationship decouples or reverses in persons having brain impairments. Five Broca’s aphasics with five matched cognitively healthy controls underwent overt picture-naming magnetoencephalography scans. The gamma-band (30–45 Hz) phase-locking values were calculated as connections among the ROIs. We calculated the partial correlation coefficients between the amplitudes and network measures and detected four node types, including hothubs with high amplitude and high connectivity, coldhubs with high connectivity but lower amplitude, non-hub hotspots, and non-hub coldspots. The results indicate that the high-amplitude regions are not necessarily highly connected hubs. Furthermore, the Broca aphasics utilized different hothub sets for the naming task. Both groups had dark functional networks composed of coldhubs. Thus, source amplitude–functional connectivity relationships could help reveal functional reorganizations in patients. The amplitude–connectivity combination provides a new perspective for pathological studies of the brain’s dark functional networks.

Can genetic polymorphisms predict response variability to anodal transcranial direct current stimulation of the primary motor cortex?

Genetic mediation of cortical plasticity and the role genetic variants play in previously observed response variability to transcranial direct current stimulation (tDCS) have become important issues in the tDCS literature in recent years. This study investigated whether inter-individual variability to tDCS was in-part genetically mediated. In 61 healthy males, anodal-tDCS (a-tDCS) and sham-tDCS were administered to the primary motor cortex at 1 mA for 10-min via 6 × 4 cm active and 7 × 5 cm return electrodes. Twenty-five single-pulse transcranial magnetic stimulation (TMS) motor evoked potentials (MEP) were recorded to represent corticospinal excitability (CSE). Twenty-five paired-pulse MEPs were recorded with 3 ms inter-stimulus interval (ISI) to assess intracortical inhibition (ICI) via short-interval intracranial inhibition (SICI) and 10 ms ISI for intracortical facilitation (ICF). Saliva samples were tested for specific genetic polymorphisms in genes encoding for excitatory and inhibitory neuroreceptors. Individuals were sub-grouped based on a pre-determined threshold and via statistical cluster analysis. Two distinct subgroups were identified, increases in CSE following a-tDCS (i.e. Responders) and no increase or even reductions in CSE (i.e. Non-responders). No changes in ICI or ICF were reported. No relationships were reported between genetic polymorphisms in excitatory receptor genes and a-tDCS responders. An association was reported between a-tDCS responders and GABRA3 gene polymorphisms encoding for GABA-A receptors suggesting potential relationships between GABA-A receptor variations and capacity to undergo tDCS-induced cortical plasticity. In the largest tDCS study of its kind, this study presents an important step forward in determining the contribution genetic factors play in previously observed inter-individual variability to tDCS.

The management of subacute and chronic vascular aphasia: an updated review

Background

Post-stroke aphasia (PSA) is an impairment of the generation or comprehension of language due to acute cerebrovascular lesions. Subacute phase span the 7th day to 24 weeks post-onset while > 6 months is termed chronic phase. Language recovery does not arise immediately in chronic PSA, unlike the acute phase. The majority of the treatment modalities in these two PSA phases are still in the infancy stage, facing dilemmas and considered experimental requiring constant updates. Hence, we aimed to upgrade the existing literature regarding available PSA management options, advances, and drawbacks pertaining to subacute and chronic phases.

Main text

In this review, we analyzed the management options for subacute and chronic vascular aphasia. MEDLINE, through PubMed, ScienceDirect, and Google Scholar were explored for English studies by utilizing the terms “stroke aphasia” Plus “vascular aphasia”; 160,753 articles were retrieved. The latest studies, published from 2016 to July 2020, were selected. Article headings and abstracts were analyzed for relevance and filtered; eventually, 92 articles were included in this review. Various management options were extracted as follows: noninvasive brain stimulation (NIBS), technology-based therapies, speech-language therapy (SLT), pharmacotherapy, music-based therapies, and psychosocial interventions.

Conclusion

The PSA therapy evolves towards more intense SLT therapy, yet the optimal dosage of the emerging high-intensity therapies is controversial. As spinal and cerebellar NIBS, Telespeech, and E-mental health mark PSA's future, distinct pharmacological options remain a dilemma. Across the continuum of care, PSA–depression comorbidity and inadequate PSA post-discharge education to patient’s families are the significant therapeutic challenges. Future therapeutic mechanisms, optimal dose/timing, and tolerability/safety exploration are obliged.

Early non-invasive brain stimulation with modified constraint-induced movement therapy for motor and functional upper limb recovery in stroke patients: Study protocol

Introduction

Upper limb motor impairment after a stroke is an important sequela. Constraint-induced movement therapy is a rehabilitation approach that has strong evidence. The incorporation of transcranial direct-current stimulation has been proposed; however, there is a lack of studies that confirm its benefits. The principal aim is to compare the effectiveness of 7 days of active versus sham bi-hemispheric transcranial direct-current stimulation, combined with modified constraint-induced movement therapy, for motor and functional recovery of the hemiparetic upper limb in subacute stroke patients.

Method/design

Randomized, double blind, sham-controlled, parallel group clinical trial in two stroke units. Participants: adults over 18 years, at least 2 days post unihemispheric stroke event, with hemiparesis, and without severe pain, aphasia or cognitive impairment. Intervention: Patients will receive 7 days of continuous therapy and be assigned to one of the treatment groups: active bi-hemispheric transcranial direct-current stimulation or sham bi-hemispheric transcranial direct-current stimulation. Measurement: Evaluations will take place at days 0, 5, 7 and 10, and at 3rd months. The Fugl-Meyer Assessment – Upper Extremity, Wolf Motor Function Test, Functional Independence Measure and Stroke Impact Scale are considered.

Discussion

Modified constraint-induced movement therapy plus transcranial direct-current stimulation in subacute stroke patients with hemiparesis could maximize motor and functional recovery. Trial registration: ClinicalTrials.gov identifier NCT03452254.

Effect of transcranial direct-current stimulation on cognitive function in stroke patients: A systematic review and meta-analysis

OBJECTIVE

Transcranial direct-current stimulation (tDCS) is a noninvasive approach that can alter brain excitability. Several studies have shown the effectiveness of tDCS in improving language and movement function in stroke patients. However, the effect of tDCS on cognitive function after stroke remains uncertain.

METHODS

We searched Medline, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), the China National Knowledge Infrastructure, the China Science and Technology Journal Database, and the Wanfang Data Knowledge Service Platform from inception to April 2, 2019. Two reviewers independently screened the studies, extracted the data, and evaluated the quality of the included studies using the Cochrane Collaboration Risk of Bias Tool. All statistical analyses were performed in RevMan 5.3, and the mean difference (MD) or standard mean difference (SMD) were used as the pooled statistics.

RESULTS

Fifteen studies involving 820 participants were included. When compared with passive tDCS, anodal tDCS was associated with improved general cognitive performance as examined by the Minimum Mental State Examination or Montreal Cognitive Assessment (SMD = 1.31, 95% CI 0.91-1.71, P < 0.00001), attention performance (SMD = 0.66, 95% CI 0.11-1.20, P = 0.02). There was no significant difference in memory performance (SMD = 0.41, 95% CI -0.67-1.50, P = 0.46).

CONCLUSIONS

tDCS is likely to be effective for patients with cognitive impairment after stroke. The evidence for different effects based on population characteristics and stimulation methods was limited, but a real effect cannot be ruled out. More high-quality research in this field is required to determine the potential benefits of tDCS in the treatment of cognitive deficits after stroke and to establish the optimal treatment program.

Interaction Between Recovery of Motor and Language Abilities After Stroke

OBJECTIVE

To analyze the nature of the interaction between motor and language recovery in patients with motor impairment and aphasia following left hemispheric stroke and to investigate prognostic factors of best recovery, that is, the significant recovery of both functions simultaneously.

DESIGN

Retrospective cohort study.

SETTING

Specialized inpatient rehabilitation facility.

PARTICIPANTS

Patients (N=435) with left hemispheric stroke in the postacute phase with motor impairment and aphasia.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURE

Patients who reached the minimal clinically important difference in the motor-FIM (M-FIM) were classified as motor responders, patients who reached a significant change in Aachen Aphasia Test were classified as language responders, and patients who reached a simultaneous and significant improvement in both functions were classified as motor and language responders.

RESULTS

Of the sample 45% were motor responders, 58% were language responders, and 35% were motor and language responders. Responder groups showed lower motor impairment and less severe aphasia at admission and greater improvement in both functions at discharge compared with nonresponder groups. Premorbid autonomy, dysphagia, apraxia, and number of rehabilitative sessions were also significantly different between groups. A logistic regression model identified M-FIM, repetition abilities, and number of sessions of speech and language therapy as independent predictors of best response (ie, motor and language responders).

CONCLUSIONS

This study provides evidence about a possible interaction between motor and language recovery after stroke. The improvement in one function was never associated with deterioration in the other. The results actually suggest a synergic effect between the amelioration of the 2 functions, with an overall increased efficiency when the 2 recovery pathways are combined.

[Noninvasive brain stimulation in the rehabilitation of patients with post-stroke aphasia]

Over the past decade, non-invasive brain stimulation, in particular transcranial stimulation by direct electric current (TES), has been increasingly included in the array of methods used for rehabilitation of patients with post-stroke impairments (motor, speech, cognitive). Development of stimulation protocols with determination of the zones of exposure, as well as better understanding of the patterns of restoration of functional systems, became possible due to basic research using functional MRI paradigm. However, the complexity of the organization of the speech system, the variety of forms of aphasia that occur when it is damaged, the individual variability of neuroplastic processes, motivated a search for optimal stimulation protocols that contribute to the personification of the rehabilitation process. Portability, low cost of equipment, a good safety and tolerance profile, as well as a proven effect on neuroplasticity processes, are the undoubted advantages of TES-therapy. There is reason to believe that further study and clinical testing of this technique will turn it into the promising tool for enhancing the effectiveness of classical speech therapy approaches in patients with post-stroke aphasia.

Impact of Combined Transcranial Direct Current Stimulation and Speech-language Therapy on Spontaneous Speech in Aphasia: A Randomized Controlled Double-blind Study

OBJECTIVE

Aphasia recovery depends on neural reorganization, which can be enhanced by speech-language therapy and noninvasive brain stimulation. Several studies suggested that transcranial direct current stimulation (tDCS) associated with speech-language therapy may improve verbal performance evaluated by analytic tests, but none focused on spontaneous speech. We explored the effect of bihemispheric tDCS on spontaneous speech in patients with poststroke aphasia.

METHODS

In this multicentric controlled randomized cross-over double-blind study, we included 10 patients with poststroke aphasia (4 had aphasia >6 months and 6 with aphasia <6 months). We combined the sessions of speech-language therapy and bihemispheric tDCS (2 mA, 20 min). After three baseline speech evaluations (1/week), two different conditions were randomly consecutively proposed: active and sham tDCS over 3 weeks with 1 week of washout in between. The main outcome measure was the number of different nouns used in 2 min to answer the question "what is your job."

RESULTS

There was no significant difference between conditions concerning the main outcome measure (p = .47) nor in the number of verbs, adjectives, adverbs, pronouns, repetitions, blank ideas, ideas, utterances with grammatical errors or paraphasias used. Other cognitive functions (verbal working memory, neglect, or verbal fluency) were not significantly improved in the tDCS group. No adverse events occurred.

CONCLUSION

Our results differed from previous studies using tDCS to improve naming in patients with poststroke aphasia possibly due to bihemispheric stimulation, rarely used previously. The duration of the rehabilitation period was short given the linguistic complexity of the measure. This negative result should be confirmed by larger studies with ecological measures.

Corticostriatal functional connectivity of bothersome tinnitus in single-sided deafness

Subjective tinnitus is an auditory phantom perceptual disorder without an objective biomarker. Bothersome tinnitus in single-sided deafness (SSD) is particularly challenging to treat because the deaf ear can no longer be stimulated by acoustic means. We contrasted an SSD cohort with bothersome tinnitus (TIN; N = 15) against an SSD cohort with no or non-bothersome tinnitus (NO TIN; N = 15) using resting-state functional magnetic resonance imaging (fMRI). All study participants had normal hearing in one ear and severe or profound hearing loss in the other. We evaluated corticostriatal functional connectivity differences by placing seeds in the caudate nucleus and Heschl’s Gyrus (HG) of both hemispheres. The TIN cohort showed increased functional connectivity between the left caudate and left HG, and left and right HG and the left caudate. Within the TIN cohort, functional connectivity between the right caudate and cuneus was correlated with the Tinnitus Functional Index (TFI) relaxation subscale. And, functional connectivity between the right caudate and superior lateral occipital cortex, and the right caudate and anterior supramarginal gyrus were correlated with the TFI control subscale. These findings support a striatal gating model of tinnitus and suggest tinnitus biomarkers to monitor treatment response and to target specific brain areas for innovative neuromodulation therapies.