title: A testbed for optimizing electrodes embedded in the skull or in artificial skull replacement pieces used after injury.
abstract: Custom-fitted skull replacement pieces are often used after a head injury or surgery to replace damaged bone. Chronic brain recordings are beneficial after injury/surgery for monitoring brain health and seizure development. Embedding electrodes directly in these artificial skull replacement pieces would be a novel, low-risk way to perform chronic brain monitoring in these patients. Similarly, embedding electrodes directly in healthy skull would be a viable minimally-invasive option for many other neuroscience and neurotechnology applications requiring chronic brain recordings.
  
  
  
  We demonstrate a preclinical testbed that can be used for refining electrode designs embedded in artificial skull replacement pieces or for embedding directly into the skull itself. Options are explored to increase the surface area of the contacts without increasing recording contact diameter to maximize recording resolution.
  
  
  
  Embedding electrodes in real or artificial skull allows one to lower electrode impedance without increasing the recording contact diameter by making use of conductive channels that extend into the skull. The higher density of small contacts embedded in the artificial skull in this testbed enables one to optimize electrode spacing for use in real bone.
  
  
  
  For brain monitoring applications, skull-embedded electrodes fill a gap between electroencephalograms recorded on the scalp surface and the more invasive epidural or subdural electrode sheets.
  
  
  
  Embedding electrodes into the skull or in skull replacement pieces may provide a safe, convenient, minimally-invasive alternative for chronic brain monitoring. The manufacturing methods described here will facilitate further testing of skull-embedded electrodes in animal models.
authors.affiliation: Department of Neurosciences, The Cleveland Clinic, Cleveland, OH 44195, United States; Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, United States; Cleveland Functional Electrical Stimulation (FES) Center of Excellence, Louis Stokes VA Medical Center, Cleveland, OH 44106, United States.
authors.forename: JingLe
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Department of Neurosciences, The Cleveland Clinic, Cleveland, OH 44195, United States; Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, United States; Cleveland Functional Electrical Stimulation (FES) Center of Excellence, Louis Stokes VA Medical Center, Cleveland, OH 44106, United States; Human Research and Engineering Directorate, US Army Research Laboratory, Aberdeen Proving Ground, MD 21005, United States.
authors.forename: Amar R
authors.initials: AR
authors.lastname: Marathe
authors.affiliation: Department of Neurosciences, The Cleveland Clinic, Cleveland, OH 44195, United States; Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, United States; Cleveland Functional Electrical Stimulation (FES) Center of Excellence, Louis Stokes VA Medical Center, Cleveland, OH 44106, United States.
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Keene
authors.affiliation: Department of Neurosciences, The Cleveland Clinic, Cleveland, OH 44195, United States; Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, United States; Cleveland Functional Electrical Stimulation (FES) Center of Excellence, Louis Stokes VA Medical Center, Cleveland, OH 44106, United States. Electronic address: dawn.taylor@case.edu.
authors.forename: Dawn M
authors.initials: DM
authors.lastname: Taylor
mesh_terms: D000818:Animals; D006259:Craniocerebral Trauma / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D004567:Electrodes, Implanted; D004569:Electroencephalography; D021621:Imaging, Three-Dimensional; D008253:Macaca mulatta; D008279:Magnetic Resonance Imaging; D019933:Ossicular Replacement / Q000379:methods*; D012886:Skull / Q000503:physiopathology*; D014057:Tomography, X-Ray Computed
keywords: Brain monitoring; Brain-machine interface (BMI); Cranioplasty; Electrocorticogram (ECoG); Impedance; Skull-embedded electrodes; Traumatic brain injury (TBI)