Otology & Neurotology 35:1658Y1661 Ó 2014, Otology & Neurotology, Inc.
Cognitive Delay as a Risk Factor for Late Presentation of Vestibular Schwannoma *‡Matthew L. Carlson, *George B. Wanna, ‡§Colin L. Driscoll, †Kyle D. Weaver, and ‡§Michael J. Link *Department of OtolaryngologyYHead and Neck Surgery, ÞDepartment of Neurologic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee; þDepartment of OtolaryngologyYHead and Neck Surgery, and §Department of Neurologic Surgery, Mayo Clinic School of Medicine, Rochester, Minnesota, U.S.A.
Objective: The majority of patients with vestibular schwannoma (VS) initially experience audiovestibular dysfunction prompting medical evaluation. Over the past several years, the authors have noticed a significant disparity in clinical presentation among patients with preexisting cognitive impairment compared with the general population. The objective of the current study is to review the clinical presentation of 5 consecutive patients with baseline cognitive delay who were ultimately diagnosed with VS. Design: Retrospective review. Setting: Two tertiary academic referral centers. Patients: Consecutive subjects with baseline cognitive impairment who were evaluated for VS between 2010 and 2013. Main Outcome Measures: Presenting symptoms and tumor characteristics. Results: Five adult subjects were identified. The most common reasons for seeking medical care included worsening ataxia and headaches, despite the fact that all patients had profound ipsilateral
hearing loss. Additionally, 2 patients endorsed facial numbness, and 2 had partial facial paresis. MRI revealed a median preoperative tumor size of 4.7 cm (4.3Y5.7 cm), and all patients had varying degrees of hydrocephalus and peritumoral vasogenic edema. Conclusion: Preexisting cognitive impairment is a risk factor for late presentation of VS. Patients with normal cognitive function most commonly seek medical care after unilateral hearing loss and tinnitus. In contrast, individuals with poor cognitive capacity may be unable to acknowledge such symptoms or communicate their presence. In such patients, the diagnosis of VS is elusive, and clinicians should maintain a low threshold for imaging to avoid further delays in diagnosis and treatment. Key Words: Acoustic neuromaVCerebellopontine angleVCognitive delayVInternal auditory canalVMental retardationVVestibular schwannoma. Otol Neurotol 35:1658Y1661, 2014.
Vestibular schwannomas (VS) are benign slowgrowing neoplasms that arise from the vestibular component of the VIIIth cranial nerve. Overall, they account for 8% of intracranial tumors and are unilateral in 95% of patients. Heralding symptoms most commonly include ipsilateral tinnitus and and hearing loss, whereas facial paresis, trigeminal neuropathy, and hydrocephalus are generally late sequelae. Owing to improved VS screening protocols for patients with asymmetric hearing loss and ever-increasing access to clinical imaging, the incidence of disease has steadily risen while the average size at diagnosis continues to decrease (1).
Despite such advances, a minority of patients still present with very late disease. Over the past several years, the authors have noticed a significant disparity in clinical presentation and tumor size among patients with preexisting cognitive impairment compared with other patients with sporadic VS. Without question, in our experience, this unique subgroup of patients has the largest tumor size and most advanced disease at diagnosis. The objective of the current study is to review the clinical presentation of 5 consecutive patients with varying severities of baseline cognitive disability who were ultimately diagnosed with VS. METHODS After institutional review board approval, a retrospective chart review at 2 tertiary academic referral centers was conducted. All consecutive subjects with baseline cognitive impairment who were evaluated for VS between 2010 and 2013 were identified. Details regarding clinical presentation including relevant history,
Address correspondence and reprint requests to Michael J. Link, M.D., Department of Neurologic Surgery, Mayo Clinic, 200 First St SW, Rochester, MN 55905; E-mail: [email protected] IRB Approval Number: 13-008813 The authors disclose no conflicts of interest.
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Copyright © 2014 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
COGNITIVE DELAY AS A RISK FACTOR FOR LARGE VS physical exam findings, and results of radiologic and audiometric testing are summarized.
RESULTS Patient Summary Between 2010 and 2013, five patients met inclusion criteria and were studied. All subjects were previously diagnosed with varying degrees of long-standing cognitive disability; however, the results of previous cognitive assessments were not available for review. Four patients were female, and the median age at diagnosis was 33 years (range, 25Y49 yr). Two patients were diagnosed with syndromic mild mental retardation associated with LEAPARD syndrome and macrocephaly-capillary malformation syndrome, and one had neonatal intraventricular hemorrhage with resultant cognitive delay; in 2 cases, the cause for cognitive delay was not known. The most common reasons for seeking medical care included headaches, and progressive ataxia; no patient presented for audiovestibular complaints, despite the fact that the 4 patients who were able to complete behavioral audiometry all demonstrated profound hearing loss in the ipsilateral ear. Additionally, after further prompting, 2 patients endorsed facial numbness, and 2 had partial facial palsy on physical examination. MRI revealed a median preoperative tumor size of 4.7 cm (4.3Y5.7 cm), and all patients had varying degrees of hydrocephalus and peritumoral vasogenic edema. Pathologic analysis revealed benign schwannoma in all cases.
1659
of the head was obtained, revealing a large posterior fossa mass with brainstem compression. Subsequent MRI demonstrated a 5.7-cm lesion consistent with VS resulting in significant brainstem compression and obstructive hydrocephalus (Fig. 1). The patient was stabilized in the neurosurgical intensive care unit and subsequently underwent subtotal resection via retrosigmoid craniotomy. Patient 2 A 49-year-old woman with mental retardation and a history of anoxic brain injury from prolonged pediatric seizures presented for evaluation after her parents noticed progressive gait instability with frequent falls and weight loss. A local neurologist obtained a head MRI, which revealed a left-sided 4.5-cm cerebellopontine angle tumor consistent with VS, resulting in considerable brainstem compression and fourth ventricle effacement. Audiogram revealed right profound hearing loss. After reviewing options, the patient underwent a left translabyrinthine approach with subtotal resection.
Case Series
Patient 3 A 33-year-old woman with mild cognitive impairment presented with worsening headaches and progressive imbalance. On exam, she was found to have a right HB grade 2 facial paresis, and audiometric testing revealed profound ipsilateral sensorineural hearing loss. An MRI of the head was obtained, which revealed a right-sided 4.5 cm VS with early hydrocephalus. After reviewing options, the patient and family elected to undergo surgery, and gross total resection was performed using a right translabyrinthine approach.
Patient 1 A 25-year-old woman with a history of neonatal intraventricular hemorrhage, ventriculoperitoneal shunt dependence, cognitive delay, and epilepsy presented for evaluation of escalating seizure activity, progressive unilateral facial palsy, and worsening imbalance. On examination, she had advanced hearing loss and right-sided House-Brackmann (HB) grade 3 facial paresis. A CT scan
Patient 4 A 39-year-old man with LEAPARD syndrome and associated mild mental retardation initially presented to an outside hospital after a 6-month history of progressive headaches and ataxia without audiovestibular complaints. After a fall with minor trauma, a CT of the head was obtained, revealing a left-sided 4.3-cm cerebellopontine angle mass with internal hemorrhage (Fig. 2). Subsequent
FIG. 1. Coronal (A) and axial contrast enhanced T1-weighted sequences (B) demonstrating a right-sided 5.7 cm VS (white arrows) resulting in significant brainstem compression. Axial T2-weighted MRI (C) demonstrating significant obstructive hydrocephalus (black arrow) from fourth ventricle effacement. Otology & Neurotology, Vol. 35, No. 9, 2014
Copyright © 2014 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
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M. L. CARLSON ET AL.
FIG. 2. Axial T1-weightedd MRI without (A) and with gadolinium (B) demonstrating a left-sided 4.3 cm VS (white arrows). Several areas of subacute intratumoral hemorrhage can be seen. Axial FLAIR sequence (C) demonstrating moderate edema of the surrounding brainstem and cerebellum.
MRI confirmed the diagnosis of VS with mild hydrocephalus. The patient underwent a retrosigmoid craniotomy elsewhere at which time considerable bleeding was encountered during the approach. The surgery was aborted without tumor resection, and the patient was transferred to the author’s institution for further care. On exam, he had an ataxic gait with normal facial nerve function. Audiometric testing revealed left profound hearing loss. After reviewing options, the patient underwent a gross total left translabyrinthine resection with external ventricular drain (EVD) placement. Patient 5 A 29-year-old developmentally delayed woman with macrocephaly-capillary malformation syndrome presented with a 10-month history of progressive headaches and imbalance with presyncopal episodes. After a negative cardiac evaluation, CT of the head revealed a very large left cerebellopontine angle mass, and subsequent MRI confirmed the diagnosis of a 5.4 cm vestibular schwannoma (Fig. 3). Additionally, she was found to have three other small meningiomas involving the left tentorium, the
occipital convexity near the superior sagittal sinus, and the right frontal convexity. Physical examination revealed intact visual acuity, normal facial nerve function, and an unstable wide-based gait. Despite having never complained of hearing loss, audiometric evaluation confirmed ipsilateral anacusis. The patient was brought to the operating room and underwent a left retrosigmoid craniotomy with gross total resection and EVD placement. DISCUSSION Before the advent of sophisticated diagnostic testing, the majority of patients with VS were diagnosed only after developing very late symptoms including headache, cranial neuropathy ataxia, and blindness. In his monologue, Tumors of the Nervus Acusticus and the Syndrome of the Cerebellopontine Angle, Harvey Cushing was the first to outline the natural progression of disease beginning with auditory and vestibular dysfunction, with succession to cerebellar ataxia, cranial neuropathy, signs and symptoms of hydrocephalus, dysphagia, depressed respiratory drive, and death (2).
FIG. 3. Axial (A) and sagittal T1-weighted sequences (B) demonstrating a 5.4 cm right-sided VS (white arrows) resulting in fourth ventricle occlusion and hydrocephalus. Several additional small meningiomas are also seen involving the tentorium and paramedian occipital convexity. Otology & Neurotology, Vol. 35, No. 9, 2014
Copyright © 2014 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
COGNITIVE DELAY AS A RISK FACTOR FOR LARGE VS Understanding that the morbidity of treatment increases with tumor size, significant efforts have been directed toward the development of early screening protocols to minimize delay in diagnosis. Improved technology and greater patient access to clinical imaging, refinements in audiometric testing, and greater disease awareness have led to a substantial increase in the incidence of disease and decrease in the average tumor size at diagnosis (1,3). Previous authors have found that the mean time interval between symptom onset and diagnosis of sporadic VS ranges from 29 to 84 months (4). Studies have suggested that patients with less advanced education, low socioeconomic status, and poor access to advanced medical care are at a higher risk of prolonged time to diagnosis (5,6). Additionally, the small subset of patients with symmetrical hearing may delay evaluation until more advanced symptoms manifest (7). In the current study, we reviewed 5 consecutive patients with baseline cognitive delay that were diagnosed with VS. The tumor size for the 5 study patients ranged from 4.3 to 5.7 cm, which is greater than the 95th percentile for patients that underwent microsurgical resection within the past decade, demonstrating that these subjects are true outliers compared with patients with normal cognitive capacity. Supposing an average growth rate of 2 to 4 mm/year, it is very likely that these patients harbored growing VS for a minimum of 1 to 2 decades. Despite having unilateral hearing loss for a significant period, it was only after others noticed visible outward signs of advanced disease including motor cranial neuropathy, seizures, weight loss, and ataxia with falls that the patient underwent medical evaluation. This study demonstrates that patients with impaired cognitive function are less likely to acknowledge or communicate cardinal symptoms of hearing loss or tinnitus. These findings underscore the importance of recognizing the full spec-
1661
trum of disease manifestations to prevent additional delays in diagnostic testing.
CONCLUSION Preexisting cognitive impairment is a risk factor for late presentation of VS. In the current series, the median tumor size at time of diagnosis was 4.7 cm (4.3Y5.7 cm), and all subjects presented only after developing advanced symptoms associated with hydrocephalus. Patients with normal cognitive function most commonly seek medical care after unilateral hearing loss and tinnitus. In contrast, individuals with poor cognitive capacity may be unable to acknowledge such symptoms and communicate their presence. In such cases, the diagnosis of VS is elusive, and clinicians should maintain a low threshold for imaging to avoid further delays in diagnosis and treatment. REFERENCES 1. Stangerup SE, Tos M, Thomsen J, et al. True incidence of vestibular schwannoma? Neurosurgery 2010;67:1335Y40; discussion 40. 2. Cushing H. Tumors of the Nervus Acusticus and the Syndrome of the Cerbellopontile Angle. W.B. Philadelphia, PA: Saunders Company, 1917. 3. Glasscock ME 3rd, Levine SC, McKennan K. The changing characteristics of acoustic neuroma patients over the last 10 years. Laryngoscope 1987;97:1164Y7. 4. van Leeuwen JP, Cremers CW, Thewissen NP, et al. Acoustic neuroma: correlation among tumor size, symptoms, and patient age. Laryngoscope 1995;105:701Y7. 5. Inskip PD, Tarone RE, Hatch EE, et al. Sociodemographic indicators and risk of brain tumours. Int J Epidemiol 2003;32:225Y33. 6. Schuz J, Steding-Jessen M, Hansen S, et al. Sociodemographic factors and vestibular schwannoma: a Danish nationwide cohort study. Neurooncol 2010;12:1291Y9. 7. Lustig LR, Rifkin S, Jackler RK, et al. Acoustic neuromas presenting with normal or symmetrical hearing: factors associated with diagnosis and outcome. Am J Otol 1998;19:212Y8.
Otology & Neurotology, Vol. 35, No. 9, 2014
Copyright © 2014 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
Cognitive Delay as a Risk Factor for Late Presentation of Vestibular Schwannoma *‡Matthew L. Carlson, *George B. Wanna, ‡§Colin L. Driscoll, †Kyle D. Weaver, and ‡§Michael J. Link *Department of OtolaryngologyYHead and Neck Surgery, ÞDepartment of Neurologic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee; þDepartment of OtolaryngologyYHead and Neck Surgery, and §Department of Neurologic Surgery, Mayo Clinic School of Medicine, Rochester, Minnesota, U.S.A.
Objective: The majority of patients with vestibular schwannoma (VS) initially experience audiovestibular dysfunction prompting medical evaluation. Over the past several years, the authors have noticed a significant disparity in clinical presentation among patients with preexisting cognitive impairment compared with the general population. The objective of the current study is to review the clinical presentation of 5 consecutive patients with baseline cognitive delay who were ultimately diagnosed with VS. Design: Retrospective review. Setting: Two tertiary academic referral centers. Patients: Consecutive subjects with baseline cognitive impairment who were evaluated for VS between 2010 and 2013. Main Outcome Measures: Presenting symptoms and tumor characteristics. Results: Five adult subjects were identified. The most common reasons for seeking medical care included worsening ataxia and headaches, despite the fact that all patients had profound ipsilateral
hearing loss. Additionally, 2 patients endorsed facial numbness, and 2 had partial facial paresis. MRI revealed a median preoperative tumor size of 4.7 cm (4.3Y5.7 cm), and all patients had varying degrees of hydrocephalus and peritumoral vasogenic edema. Conclusion: Preexisting cognitive impairment is a risk factor for late presentation of VS. Patients with normal cognitive function most commonly seek medical care after unilateral hearing loss and tinnitus. In contrast, individuals with poor cognitive capacity may be unable to acknowledge such symptoms or communicate their presence. In such patients, the diagnosis of VS is elusive, and clinicians should maintain a low threshold for imaging to avoid further delays in diagnosis and treatment. Key Words: Acoustic neuromaVCerebellopontine angleVCognitive delayVInternal auditory canalVMental retardationVVestibular schwannoma. Otol Neurotol 35:1658Y1661, 2014.
Vestibular schwannomas (VS) are benign slowgrowing neoplasms that arise from the vestibular component of the VIIIth cranial nerve. Overall, they account for 8% of intracranial tumors and are unilateral in 95% of patients. Heralding symptoms most commonly include ipsilateral tinnitus and and hearing loss, whereas facial paresis, trigeminal neuropathy, and hydrocephalus are generally late sequelae. Owing to improved VS screening protocols for patients with asymmetric hearing loss and ever-increasing access to clinical imaging, the incidence of disease has steadily risen while the average size at diagnosis continues to decrease (1).
Despite such advances, a minority of patients still present with very late disease. Over the past several years, the authors have noticed a significant disparity in clinical presentation and tumor size among patients with preexisting cognitive impairment compared with other patients with sporadic VS. Without question, in our experience, this unique subgroup of patients has the largest tumor size and most advanced disease at diagnosis. The objective of the current study is to review the clinical presentation of 5 consecutive patients with varying severities of baseline cognitive disability who were ultimately diagnosed with VS. METHODS After institutional review board approval, a retrospective chart review at 2 tertiary academic referral centers was conducted. All consecutive subjects with baseline cognitive impairment who were evaluated for VS between 2010 and 2013 were identified. Details regarding clinical presentation including relevant history,
Address correspondence and reprint requests to Michael J. Link, M.D., Department of Neurologic Surgery, Mayo Clinic, 200 First St SW, Rochester, MN 55905; E-mail: [email protected] IRB Approval Number: 13-008813 The authors disclose no conflicts of interest.
1658
Copyright © 2014 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
COGNITIVE DELAY AS A RISK FACTOR FOR LARGE VS physical exam findings, and results of radiologic and audiometric testing are summarized.
RESULTS Patient Summary Between 2010 and 2013, five patients met inclusion criteria and were studied. All subjects were previously diagnosed with varying degrees of long-standing cognitive disability; however, the results of previous cognitive assessments were not available for review. Four patients were female, and the median age at diagnosis was 33 years (range, 25Y49 yr). Two patients were diagnosed with syndromic mild mental retardation associated with LEAPARD syndrome and macrocephaly-capillary malformation syndrome, and one had neonatal intraventricular hemorrhage with resultant cognitive delay; in 2 cases, the cause for cognitive delay was not known. The most common reasons for seeking medical care included headaches, and progressive ataxia; no patient presented for audiovestibular complaints, despite the fact that the 4 patients who were able to complete behavioral audiometry all demonstrated profound hearing loss in the ipsilateral ear. Additionally, after further prompting, 2 patients endorsed facial numbness, and 2 had partial facial palsy on physical examination. MRI revealed a median preoperative tumor size of 4.7 cm (4.3Y5.7 cm), and all patients had varying degrees of hydrocephalus and peritumoral vasogenic edema. Pathologic analysis revealed benign schwannoma in all cases.
1659
of the head was obtained, revealing a large posterior fossa mass with brainstem compression. Subsequent MRI demonstrated a 5.7-cm lesion consistent with VS resulting in significant brainstem compression and obstructive hydrocephalus (Fig. 1). The patient was stabilized in the neurosurgical intensive care unit and subsequently underwent subtotal resection via retrosigmoid craniotomy. Patient 2 A 49-year-old woman with mental retardation and a history of anoxic brain injury from prolonged pediatric seizures presented for evaluation after her parents noticed progressive gait instability with frequent falls and weight loss. A local neurologist obtained a head MRI, which revealed a left-sided 4.5-cm cerebellopontine angle tumor consistent with VS, resulting in considerable brainstem compression and fourth ventricle effacement. Audiogram revealed right profound hearing loss. After reviewing options, the patient underwent a left translabyrinthine approach with subtotal resection.
Case Series
Patient 3 A 33-year-old woman with mild cognitive impairment presented with worsening headaches and progressive imbalance. On exam, she was found to have a right HB grade 2 facial paresis, and audiometric testing revealed profound ipsilateral sensorineural hearing loss. An MRI of the head was obtained, which revealed a right-sided 4.5 cm VS with early hydrocephalus. After reviewing options, the patient and family elected to undergo surgery, and gross total resection was performed using a right translabyrinthine approach.
Patient 1 A 25-year-old woman with a history of neonatal intraventricular hemorrhage, ventriculoperitoneal shunt dependence, cognitive delay, and epilepsy presented for evaluation of escalating seizure activity, progressive unilateral facial palsy, and worsening imbalance. On examination, she had advanced hearing loss and right-sided House-Brackmann (HB) grade 3 facial paresis. A CT scan
Patient 4 A 39-year-old man with LEAPARD syndrome and associated mild mental retardation initially presented to an outside hospital after a 6-month history of progressive headaches and ataxia without audiovestibular complaints. After a fall with minor trauma, a CT of the head was obtained, revealing a left-sided 4.3-cm cerebellopontine angle mass with internal hemorrhage (Fig. 2). Subsequent
FIG. 1. Coronal (A) and axial contrast enhanced T1-weighted sequences (B) demonstrating a right-sided 5.7 cm VS (white arrows) resulting in significant brainstem compression. Axial T2-weighted MRI (C) demonstrating significant obstructive hydrocephalus (black arrow) from fourth ventricle effacement. Otology & Neurotology, Vol. 35, No. 9, 2014
Copyright © 2014 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
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M. L. CARLSON ET AL.
FIG. 2. Axial T1-weightedd MRI without (A) and with gadolinium (B) demonstrating a left-sided 4.3 cm VS (white arrows). Several areas of subacute intratumoral hemorrhage can be seen. Axial FLAIR sequence (C) demonstrating moderate edema of the surrounding brainstem and cerebellum.
MRI confirmed the diagnosis of VS with mild hydrocephalus. The patient underwent a retrosigmoid craniotomy elsewhere at which time considerable bleeding was encountered during the approach. The surgery was aborted without tumor resection, and the patient was transferred to the author’s institution for further care. On exam, he had an ataxic gait with normal facial nerve function. Audiometric testing revealed left profound hearing loss. After reviewing options, the patient underwent a gross total left translabyrinthine resection with external ventricular drain (EVD) placement. Patient 5 A 29-year-old developmentally delayed woman with macrocephaly-capillary malformation syndrome presented with a 10-month history of progressive headaches and imbalance with presyncopal episodes. After a negative cardiac evaluation, CT of the head revealed a very large left cerebellopontine angle mass, and subsequent MRI confirmed the diagnosis of a 5.4 cm vestibular schwannoma (Fig. 3). Additionally, she was found to have three other small meningiomas involving the left tentorium, the
occipital convexity near the superior sagittal sinus, and the right frontal convexity. Physical examination revealed intact visual acuity, normal facial nerve function, and an unstable wide-based gait. Despite having never complained of hearing loss, audiometric evaluation confirmed ipsilateral anacusis. The patient was brought to the operating room and underwent a left retrosigmoid craniotomy with gross total resection and EVD placement. DISCUSSION Before the advent of sophisticated diagnostic testing, the majority of patients with VS were diagnosed only after developing very late symptoms including headache, cranial neuropathy ataxia, and blindness. In his monologue, Tumors of the Nervus Acusticus and the Syndrome of the Cerebellopontine Angle, Harvey Cushing was the first to outline the natural progression of disease beginning with auditory and vestibular dysfunction, with succession to cerebellar ataxia, cranial neuropathy, signs and symptoms of hydrocephalus, dysphagia, depressed respiratory drive, and death (2).
FIG. 3. Axial (A) and sagittal T1-weighted sequences (B) demonstrating a 5.4 cm right-sided VS (white arrows) resulting in fourth ventricle occlusion and hydrocephalus. Several additional small meningiomas are also seen involving the tentorium and paramedian occipital convexity. Otology & Neurotology, Vol. 35, No. 9, 2014
Copyright © 2014 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
COGNITIVE DELAY AS A RISK FACTOR FOR LARGE VS Understanding that the morbidity of treatment increases with tumor size, significant efforts have been directed toward the development of early screening protocols to minimize delay in diagnosis. Improved technology and greater patient access to clinical imaging, refinements in audiometric testing, and greater disease awareness have led to a substantial increase in the incidence of disease and decrease in the average tumor size at diagnosis (1,3). Previous authors have found that the mean time interval between symptom onset and diagnosis of sporadic VS ranges from 29 to 84 months (4). Studies have suggested that patients with less advanced education, low socioeconomic status, and poor access to advanced medical care are at a higher risk of prolonged time to diagnosis (5,6). Additionally, the small subset of patients with symmetrical hearing may delay evaluation until more advanced symptoms manifest (7). In the current study, we reviewed 5 consecutive patients with baseline cognitive delay that were diagnosed with VS. The tumor size for the 5 study patients ranged from 4.3 to 5.7 cm, which is greater than the 95th percentile for patients that underwent microsurgical resection within the past decade, demonstrating that these subjects are true outliers compared with patients with normal cognitive capacity. Supposing an average growth rate of 2 to 4 mm/year, it is very likely that these patients harbored growing VS for a minimum of 1 to 2 decades. Despite having unilateral hearing loss for a significant period, it was only after others noticed visible outward signs of advanced disease including motor cranial neuropathy, seizures, weight loss, and ataxia with falls that the patient underwent medical evaluation. This study demonstrates that patients with impaired cognitive function are less likely to acknowledge or communicate cardinal symptoms of hearing loss or tinnitus. These findings underscore the importance of recognizing the full spec-
1661
trum of disease manifestations to prevent additional delays in diagnostic testing.
CONCLUSION Preexisting cognitive impairment is a risk factor for late presentation of VS. In the current series, the median tumor size at time of diagnosis was 4.7 cm (4.3Y5.7 cm), and all subjects presented only after developing advanced symptoms associated with hydrocephalus. Patients with normal cognitive function most commonly seek medical care after unilateral hearing loss and tinnitus. In contrast, individuals with poor cognitive capacity may be unable to acknowledge such symptoms and communicate their presence. In such cases, the diagnosis of VS is elusive, and clinicians should maintain a low threshold for imaging to avoid further delays in diagnosis and treatment. REFERENCES 1. Stangerup SE, Tos M, Thomsen J, et al. True incidence of vestibular schwannoma? Neurosurgery 2010;67:1335Y40; discussion 40. 2. Cushing H. Tumors of the Nervus Acusticus and the Syndrome of the Cerbellopontile Angle. W.B. Philadelphia, PA: Saunders Company, 1917. 3. Glasscock ME 3rd, Levine SC, McKennan K. The changing characteristics of acoustic neuroma patients over the last 10 years. Laryngoscope 1987;97:1164Y7. 4. van Leeuwen JP, Cremers CW, Thewissen NP, et al. Acoustic neuroma: correlation among tumor size, symptoms, and patient age. Laryngoscope 1995;105:701Y7. 5. Inskip PD, Tarone RE, Hatch EE, et al. Sociodemographic indicators and risk of brain tumours. Int J Epidemiol 2003;32:225Y33. 6. Schuz J, Steding-Jessen M, Hansen S, et al. Sociodemographic factors and vestibular schwannoma: a Danish nationwide cohort study. Neurooncol 2010;12:1291Y9. 7. Lustig LR, Rifkin S, Jackler RK, et al. Acoustic neuromas presenting with normal or symmetrical hearing: factors associated with diagnosis and outcome. Am J Otol 1998;19:212Y8.
Otology & Neurotology, Vol. 35, No. 9, 2014
Copyright © 2014 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
