Papers by Robert Stokroos
ORL, 2015
The concept of the vestibular implant is primarily to artificially restore the vestibular functio... more The concept of the vestibular implant is primarily to artificially restore the vestibular function in patients with a bilateral vestibular loss (BVL) by providing the central nervous system with motion information using electrical stimulation of the vestibular nerve. Our group initiated human trials about 10 years ago. Between 2007 and 2013, 11 patients with a BVL received a vestibular implant prototype providing electrodes to stimulate the ampullary branches of the vestibular nerve. Eye movements were recorded and analyzed to assess the effects of the electrical stimulation. Perception induced by electrical stimulation was documented. Smooth, controlled eye movements were obtained in all patients showing that electrical stimulation successfully activated the vestibulo-ocular pathway. However, both the electrical dynamic range and the amplitude of the eye movements were variable from patient to patient. The axis of the response was consistent with the stimulated nerve branch in 17 out of the 24 tested electrodes. Furthermore, in at least 1 case, the elicited eye movements showed characteristics similar to those of compensatory eye movements observed during natural activities such as walking. Finally, diverse percepts were reported upon electrical stimulation (i.e., rotatory sensations, sound, tickling or pressure) with intensity increasing as the stimulation current increased. These results demonstrate that electrical stimulation is a safe and effective means to activate the vestibular system, even in a heterogeneous patient population with very different etiologies and disease durations. Successful tuning of this information could turn this vestibular implant prototype into a successful artificial balance organ.
Ear and hearing, 2015
Research on tinnitus suppression by intracochlear electrical stimulation has gained interest over... more Research on tinnitus suppression by intracochlear electrical stimulation has gained interest over the past few decades and it has become easier to apply since the introduction of cochlear implants (CI). This study attempted to gain more insight into optimal stimulation characteristics for tinnitus suppression. Eleven subjects with unilateral CI and tinnitus were recruited from our CI clinic. Electrical stimulation, independent of acoustic sounds, was generated using their CI. The current prospective (single blinded) experimental study systematically assessed two stimulation parameters, namely current level and the anatomical stimulation site inside the cochlea and their short-term effect on tinnitus. Approximately one-third of the tested conditions were successful in which case tinnitus loudness was reduced by at least 30%. At least one successful condition was achieved for nine subjects (82%). Complete suppression was achieved in 6 out of 107 tested conditions (6%). The effect of s...
Nederlands tijdschrift voor geneeskunde, 2013
In the Netherlands, more than 1.5 million people suffer from sensorineural hearing loss or deafne... more In the Netherlands, more than 1.5 million people suffer from sensorineural hearing loss or deafness. However, fitting conventional hearing aids does not provide a solution for everyone. In recent decades, developments in medical technology have produced implantable and other devices that restore both sensorineural and conductive hearing losses. These hearing devices can be categorized into bone conductive devices, implantable middle ear prostheses, cochlear implants and auditory brainstem implants. Furthermore, new implants aimed at treating tinnitus and loss of vestibular function have recently been developed.
Current opinion in otolaryngology & head and neck surgery, 2012
Tinnitus is a symptom that is highly associated with hearing loss. Its incidence is expected to i... more Tinnitus is a symptom that is highly associated with hearing loss. Its incidence is expected to increase due to the detrimental effects of occupational and leisure noise. Even though no standard treatment is currently available, the effect of cochlear implants on tinnitus in single-sided deafness (SSD) is under scientific attention. This review reveals an overview of all publicly available reports about cochlear implant as a treatment for tinnitus in SSD. Cochlear implantation in SSD suppresses tinnitus in most of the cases. Some studies even demonstrate complete tinnitus suppression after implantation. No tinnitus worsening is reported in any of the cases. Furthermore, tinnitus does not restore during the electrical stimulation presented by the cochlear implant. The tinnitus level seems to stabilize after 3-6 months after the first fitting. Although the underlying mechanism responsible for the observed tinnitus suppression is not yet clear, cochlear implantation should be considere...
Nederlands tijdschrift voor geneeskunde, 2012
In two patients the presenting symptoms of nasopharyngeal carcinoma were non-specific: a woman ag... more In two patients the presenting symptoms of nasopharyngeal carcinoma were non-specific: a woman aged 35 years born in Hong-Kong with unilateral hearing loss, and a man aged 59 years with acute otitis media who later developed cranial nerve palsy. The woman was successfully treated with chemotherapy and radiotherapy, the man was in a poor general condition and refused treatment; he died within 9 weeks. Nasopharyngeal carcinoma is rare and can occur at any age. Symptoms of the disease are not specific and sometimes subtle resulting in a late diagnosis and a reduced chance of cure. In South-East Asia its incidence is much higher and recognition and prognosis are better. If a malignant tumour in the nasopharynx is suspected, endoscopy may not be adequate as the tumour can grow submucosally, necessitating radiological examination with MRI or CT. MRI is the most sensitive radiological examination for the detection of this tumour and the assessment of the extent of its local and perineural ...
Ear, nose, & throat journal, 2007
Cochlear implantation is considered to be a safe and effective treatment for severe to profound s... more Cochlear implantation is considered to be a safe and effective treatment for severe to profound sensorineural hearing loss. Device failures are rare. We report the cases of 2 patients--a 44-year-old woman and a 3-year-old boy--with cochlear implants who were referred to our tertiary cochlear implant center for treatment of magnet migration secondary to mild head trauma. The migration had led to device failure in both cases. Surgical reexploration was performed with nonmagnetic instruments, and both magnets were easily returned to their proper place. Postoperatively, implant function was restored to previous levels, and wound healing was uncomplicated. The incidence of magnet migration in cochlear implant patients is unknown. A few cases have been reported in children, but to the best of our knowledge, ours is the first report of magnet migration in an adult.
International Journal of Pediatric Otorhinolaryngology, 2011
The Laryngoscope, 2013
To describe spontaneous hearing improvement in the first years of life of a number of preterm neo... more To describe spontaneous hearing improvement in the first years of life of a number of preterm neonates relative to cochlear implant candidacy. Retrospective case study. Hearing levels of 14 preterm neonates (mean gestational age at birth = 29 weeks) referred after newborn hearing screening were evaluated. Initial hearing thresholds ranged from 40 to 105 dBHL (mean = 85 dBHL). Hearing level improved to normal levels for four neonates and to moderate levels for five, whereas for five neonates, no improvement in hearing thresholds was observed and cochlear implantation was recommended. Three of the four neonates in whom the hearing improved to normal levels were born prior to 28 weeks gestational age. Hearing improvement was mainly observed prior to a gestational age of 80 weeks. Delayed maturation of an immature auditory pathway might be an important reason for referral after newborn hearing screening in premature infants. Caution is advised regarding early cochlear implantation in preterm born infants. Audiological follow-ups until at least 80 weeks gestational age are therefore recommended.
Although cochlear implantation is considered a safe method of rehabilitation for profoundly deaf ... more Although cochlear implantation is considered a safe method of rehabilitation for profoundly deaf individuals, a number of these patients suffer complications after surgery. To evaluate post-operative complications after cochlear implantation, a retrospective chart review was performed for 112 patients who had undergone implantation in the Maastricht Academic Hospital. Minor complications were defined as those that could be overcome by medical or audiological management. These occurred in 36 patients (32 per cent) and all were managed successfully. Major complications were defined as device extrusion and those requiring further surgery, and these were identified in four patients (3.6 per cent). These complications included wound infection and device failure mediated by middle-ear pathology. In cases of chronic otitis media, we recommend performance of cochlear implantation as a staged procedure. In order to reduce the post-operative incidence of acute otitis media, we recommend adenoidectomy, placement of ventilation tubes and early antibiotic treatment.
Otology & Neurotology, 2010
To determine which bone-anchored hearing aid (BAHA) implantation surgical technique is associated... more To determine which bone-anchored hearing aid (BAHA) implantation surgical technique is associated with the fewest major postoperative complications and shortest time between surgery and use of the BAHA. The techniques evaluated were 1) a free retroauricular "full-thickness" skin graft, 2) a pedicled parieto-occipital epidermal graft, 3) a dermatome-pedicled parieto-occipital dermal graft, and 4) two broad pedicled local epidermal skin envelopes/skin flaps. Retrospective case study. Tertiary referral center. One hundred forty-three patients who received a BAHA at Maastricht University Medical Center between November 1996 and January 2007. Number and mean age of patients in each group: Technique 1 (n = 30; mean age, 55 yr), Technique 2 (n = 45; mean age, 54 yr), Technique 3 (n = 47; mean age, 55 yr), and Technique 4 (n = 21; mean age, 54 yr). Cumulative proportion of implants that remained free of major complications versus follow-up interval, time between surgery and use of BAHA. Technique 4 (2 broad pedicled local epidermal envelopes/skin flaps) has a significantly higher proportion of implants that remained free of major complications during first year of follow-up (91%; p = 0.021). Pairwise comparisons revealed that Technique 4 also has a significantly shorter time until use (2 mo) than Techniques 1 (2.5 mo), 2, and 3 (both 2.3 mo). Two broad pedicled, local epidermal envelopes/flaps are associated with significantly fewer major complications and have one of the shortest times between surgery and use of the BAHA. The use of a dermatome is not associated with fewer major complications. We recommend Technique 4 as the preferred standard in BAHA surgery to minimize complications, postoperative medication, discomfort, and cost.
Otology & Neurotology, 2010
The Journal of Laryngology & Otology, 2006
Charcot-Marie-Tooth disease (CMT), also named hereditary motor and sensory neuropathies (HMSN), c... more Charcot-Marie-Tooth disease (CMT), also named hereditary motor and sensory neuropathies (HMSN), comprises a clinically and genetically heterogeneous group of disorders affecting the peripheral nervous system. Deafness induced by CMT is clinically distinct among the genetically heterogeneous group of CMT disorders. Deafness in CMT patients is associated with point mutations or deletions in the transmembrane domain in the peripheral myelin gene (PMP) 22, which are in close proximity to the extracellular component of this gene. We present a patient with deafness induced by CMT type 1A, undergoing cochlear implantation. Prior investigations showed good results due to replacing a synchronous impulse by means of cochlear implantation in patients with auditory neuropathy.
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Papers by Robert Stokroos