Localizing Broca's area for transcranial magnetic stimulation: Comparison of surface distance measurements and stereotaxic positioning.

Brain stimulation · 2009 · Unclear · Insufficient evidence

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UnclearInsufficient evidencePaper 2782

Coil positioning over Broca's area using the surface distance measurements (SDM) method differed from an advanced stereotaxic navigation system by a mean Euclidean distance of 8.31 mm. The mean difference in estimated virtual electric field intensity at the t…

Study snapshot

PublicationBrain stimulation · 2009

Study typeother

Reported directionUnclear

Evidence ratingInsufficient

Abstract

BACKGROUND: Precise placement of transcranial magnetic stimulation (TMS) coils over target regions is crucial for correct interpretation of TMS effects. Modern frameless stereotaxic systems yield high accuracy, but require extensive equipment and cannot be used in every setting, for example, during functional imaging sessions. OBJECTIVE: The aim of this study was the development of a method for TMS-coil placement based on individual imaging data without the need for external tracking devices. METHODS: We compared coil positioning over Broca's area using an advanced stereotaxic navigation system with placement according to the surface distance measurements (SDM) method. By using the SDM-method, 3-dimensional renderings adapted from individual T1-weighted magnetic resonance imaging (MRI) data were created to identify Broca's area and Broca's homologue, respectively, and to define anatomic landmarks on the skin's surface. Distances between these landmarks were used to localize the real target on the individual's head. RESULTS: The mean Euclidean distance between surface positions as determined with the two methods was 8.31 mm and the mean difference of estimated virtual electric field intensity at the target point was 7.37 V/m corresponding to 4.01% of maximum field strength. CONCLUSIONS: Our findings suggest that, compared with a state-of-the-art frameless stereotaxy system, the SDM-method yields a reasonable accuracy for positioning of a TMS-coil over Broca's area in terms of spatial coordinates.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeother

Effect directionunclear

PopulationNot supplied

Sample sizeNot supplied

ExposureNot supplied

Evidence strengthInsufficientConfidence: 74% · Peer reviewed: yes

Main findings

Outcomes measured

Accuracy of TMS coil positioning over Broca's area (Euclidean distance between methods)
Difference in estimated virtual electric field intensity at target point (V/m; % of maximum field strength)

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": null,
    "source": "transcranial magnetic stimulation (TMS) coil placement/navigation",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Accuracy of TMS coil positioning over Broca's area (Euclidean distance between methods)",
    "Difference in estimated virtual electric field intensity at target point (V/m; % of maximum field strength)"
  ],
  "main_findings": "Coil positioning over Broca's area using the surface distance measurements (SDM) method differed from an advanced stereotaxic navigation system by a mean Euclidean distance of 8.31 mm. The mean difference in estimated virtual electric field intensity at the target point was 7.37 V/m (4.01% of maximum field strength).",
  "effect_direction": "unclear",
  "limitations": [],
  "evidence_strength": "insufficient",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "transcranial magnetic stimulation",
    "TMS",
    "Broca's area",
    "stereotaxic navigation",
    "surface distance measurements",
    "MRI",
    "coil positioning",
    "electric field intensity"
  ],
  "suggested_hubs": [
    {
      "slug": "tms",
      "weight": 0.9,
      "reason": "Study evaluates methods for localizing/positioning a TMS coil over Broca's area using MRI-based landmarks versus stereotaxic navigation."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1016/j.brs.2008.09.005
PubMed: 20633406

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