Sensory and motor deficits as contributors to early cognitive impairment

INTRODUCTION

Age-related sensory and motor impairment are associated with risk of dementia. No study has examined the joint associations of multiple sensory and motor measures on prevalence of early cognitive impairment (ECI).

METHODS

Six hundred fifty participants in the Baltimore Longitudinal Study of Aging completed sensory and motor function tests. The association between sensory and motor function and ECI was examined using structural equation modeling with three latent factors corresponding to multisensory, fine motor, and gross motor function.

RESULTS

The multisensory, fine, and gross motor factors were all correlated (r = 0.74 to 0.81). The odds of ECI were lower for each additional unit improvement in the multisensory (32%), fine motor (30%), and gross motor factors (12%).

DISCUSSION

The relationship between sensory and motor impairment and emerging cognitive impairment may guide future intervention studies aimed at preventing and/or treating ECI.

HIGHLIGHTS

Sensorimotor function and early cognitive impairment (ECI) prevalence were assessed via structural equation modeling. The degree of fine and gross motor function is associated with indicators of ECI. The degree of multisensory impairment is also associated with indicators of ECI.

Acoustic Noise Levels in High-field Magnetic Resonance Imaging Scanners

7-Tesla (T) magnetic resonance imaging may allow for higher resolution images but may produce greater acoustic noise than 1.5- and 3-T scanners. We sought to characterize the intensity of acoustic noise from 7- versus 3-T scanners. A-weighted sound pressure levels from 5 types of pulse sequences used for brain and inner ear imaging in 3- and 7-T scanners were measured. Time-averaged sound level and maximum sound levels generated for each sequence were compared. Time-averaged sound levels exceeded 95 dB and reached maximums above 105 dB on the majority of 3- and 7-T scans. The mean time-averaged sound level and maximum sound level across pulse sequences were greater in 7- than 3-T (105.6 vs 91.4, P = .01; 114.0 vs. 96.5 dB, P < .01). 7- and 3-T magnetic resonance imaging scanners produce high levels of acoustic noise that exceed acceptable safety limits, emphasizing the need for active and passive noise protection.

Local spatial navigation or "steering" in patients with vestibular loss in a virtual reality environment

BACKGROUND

Patients with vestibular loss have reduced wayfinding ability, but the association between vestibular loss and impaired steering spatial navigation is unclear.

OBJECTIVE

To evaluate whether vestibular loss is associated with reduced steering navigation performance in a virtual reality (VR) environment containing obstacles.

METHODS

17 ambulatory adults with vestibular loss were age/sex-matched to healthy controls. Participants traversed a VR hallway with obstacles, and their navigation performance was compared using metrics such as collisions, time, total distance travelled, and speed in single and multivariate analysis.

RESULTS

In univariate analysis there was no significant difference in collisions between vestibular patients and controls (1.84 vs. 2.24, p = 0.974). However, vestibular patients took more time, longer routes, and had lower speeds to complete the task (56.9 vs. 43.9 seconds, p < 0.001; 23.1 vs. 22.0 meters, p = 0.0312; 0.417 vs. 0.544 m/s, p < 0.001). These results were confirmed in multivariate analysis.

CONCLUSIONS

This study found that patients with vestibular loss displayed slower gait speeds and traveled longer distances, though did not make more collisions, during a VR steering navigation task. Beyond the known influence of vestibular function on gait speed, vestibular loss may also contribute to less efficient steering navigation through an obstacle-laden environment, through neural mechanisms that remain to be elucidated.

Natural History of Cystic Vestibular Schwannomas

OBJECTIVE

To determine the natural history of cystic vestibular schwannomas (VS).

STUDY DESIGN

Retrospective cohort.

SETTING

Single tertiary academic hospital.

PATIENTS

Adults diagnosed with cystic VS who had at least 2 MRIs performed at least 6 months apart between 2008 and 2016 with no intervening treatment.

MAIN OUTCOME MEASURES

Volumetric growth rates of both the entire tumor and individual cystic and solid components were measured. Linear growth rate of the entire tumor was assessed using the largest diameter parallel to the petrous face at the cerebellopontine angle (CPA).

RESULTS

Twenty-one patients met inclusion criteria. The average volumetric growth rate of the tumor was 1.1 ± 2 (range: -1.2 to 7.8), while the average growth rate of the cystic component was 0.8 ± 1.6 (range: -0.5 to 5.3) cm³/year. The CPA diameter of the tumor demonstrated an average linear growth rate of was 1.2 ± 4.4 (range: -8to 13.5) mm/year. With regards to tumor diameter, 9/21 (42.9%) remained stable, 3/21 (14.2%) decreased in size, while 9/21 (42.9%) increased in size.

CONCLUSIONS

Cystic tumors demonstrate a wide variability in growth rate. Larger, multi-center studies will be required to further compare this relationship to solid tumors.

Repair of surviving hair cells in the damaged mouse utricle

Sensory hair cells (HCs) in the utricle are mechanoreceptors required to detect linear acceleration. After damage, the mammalian utricle partially restores the HC population and organ function, although regenerated HCs are primarily type II and immature. Whether native, surviving HCs can repair and contribute to this recovery is unclear. Here, we generated the Pou4f3DTR/+; Atoh1CreERTM/+; Rosa26RtdTomato/+ mouse to fate map HCs prior to ablation. After HC ablation, vestibular evoked potentials were abolished in all animals, with ∼57% later recovering responses. Relative to nonrecovery mice, recovery animals harbored more Atoh1-tdTomato+ surviving HCs. In both groups, surviving HCs displayed markers of both type I and type II subtypes and afferent synapses, despite distorted lamination and morphology. Surviving type II HCs remained innervated in both groups, whereas surviving type I HCs first lacked and later regained calyces in the recovery, but not the nonrecovery, group. Finally, surviving HCs initially displayed immature and subsequently mature-appearing bundles in the recovery group. These results demonstrate that surviving HCs are capable of self-repair and may contribute to the recovery of vestibular function.

Assessment of auditory and vestibular damage in a mouse model after single and triple blast exposures

The use of explosive devices in war and terrorism has increased exposure to concussive blasts among both military personnel and civilians, which can cause permanent hearing and balance deficits that adversely affect survivors' quality of life. Significant knowledge gaps on the underlying etiology of blast-induced hearing loss and balance disorders remain, especially with regard to the effect of blast exposure on the vestibular system, the impact of multiple blast exposures, and long-term recovery. To address this, we investigated the effects of blast exposure on the inner ear using a mouse model in conjunction with a high-fidelity blast simulator. Anesthetized animals were subjected to single or triple blast exposures, and physiological measurements and tissue were collected over the course of recovery for up to 180 days. Auditory brainstem responses (ABRs) indicated significantly elevated thresholds across multiple frequencies. Limited recovery was observed at low frequencies in single-blasted mice. Distortion Product Otoacoustic Emissions (DPOAEs) were initially absent in all blast-exposed mice, but low-amplitude DPOAEs could be detected at low frequencies in some single-blast mice by 30 days post-blast, and in some triple-blast mice at 180 days post-blast. All blast-exposed mice showed signs of Tympanic Membrane (TM) rupture immediately following exposure and loss of outer hair cells (OHCs) in the basal cochlear turn. In contrast, the number of Inner Hair Cells (IHCs) and spiral ganglion neurons was unchanged following blast-exposure. A significant reduction in IHC pre-synaptic puncta was observed in the upper turns of blast-exposed cochleae. Finally, we found no significant loss of utricular hair cells or changes in vestibular function as assessed by vestibular evoked potentials. Our results suggest that (1) blast exposure can cause severe, long-term hearing loss which may be partially due to slow TM healing or altered mechanical properties of healed TMs, (2) traumatic levels of sound can still reach the inner ear and cause basal OHC loss despite middle ear dysfunction caused by TM rupture, (3) blast exposure may result in synaptopathy in humans, and (4) balance deficits after blast exposure may be primarily due to traumatic brain injury, rather than damage to the peripheral vestibular system.

Atoh1 Directs Regeneration and Functional Recovery of the Mature Mouse Vestibular System

Utricular hair cells (HCs) are mechanoreceptors required for vestibular function. After damage, regeneration of mammalian utricular HCs is limited and regenerated HCs appear immature. Thus, loss of vestibular function is presumed irreversible. Here, we found partial HC replacement and functional recovery in the mature mouse utricle, both enhanced by overexpressing the transcription factor Atoh1. Following damage, long-term fate mapping revealed that support cells non-mitotically and modestly regenerated HCs displaying no or immature bundles. By contrast, Atoh1 overexpression stimulated proliferation and widespread regeneration of HCs exhibiting elongated bundles, patent mechanotransduction channels, and synaptic connections. Finally, although damage without Atoh1 overexpression failed to initiate or sustain a spontaneous functional recovery, Atoh1 overexpression significantly enhanced both the degree and percentage of animals exhibiting sustained functional recovery. Therefore, the mature, damaged utricle has an Atoh1-responsive regenerative program leading to functional recovery, underscoring the potential of a reprogramming approach to sensory regeneration.

The mature mouse utricle, which detects linear acceleration, displays limited regeneration, but whether function returns is unknown. Sayyid et al. show that regenerated hair cells appear and mature over months, resulting in a limited, unsustained functional recovery. Atoh1 overexpression enhances regeneration and leads to a sustained recovery of vestibular function.

Ambient Pressure Tympanometry Wave Patterns in Patients With Superior Semicircular Canal Dehiscence

Importance: Superior semicircular canal dehiscence (SSCD) is a treatable condition, but current diagnostic modalities have numerous limitations. Clinicians would benefit from an additional tool for diagnostic workup that is both rapid and widely available. Objective: To assess the utility of ambient pressure tympanometry (APT) in the diagnostic workup of SSCD by determining the sensitivity and specificity of APT for SSCD in comparison to other diagnostic modalities. Design: Retrospective cohort study of patients who underwent APT and temporal bone computerized tomography (CT) scans from May 2017 to July 2018. Setting: Tertiary referral center. Participants: APT was performed as part of routine audiological testing on adult patients. We retrospectively analyzed all patients who received both APT and temporal bone CT scans, and divided ears into SSCD and non-SSCD groups based on the presence or absence of radiographic SSCD. Ears with other radiographic findings that could affect tympanic membrane compliance were excluded. Exposures: All patients in this study underwent APT and temporal bone CT scans. Some patients also underwent pure tone audiometry and vestibular evoked myogenic potentials (VEMPs). Main Outcomes and Measures: The primary outcome measures were sensitivity, specificity, and risk ratio of APT for SSCD. Secondary outcome measures include sensitivity of VEMPs and supranormal hearing thresholds. Results: We describe 52 patients (70 ears) who underwent APT and CT imaging (mean age 47.1 years, 67.1% female). APT detected SSCD with 66.7% sensitivity and 72.1% specificity. In symptomatic patients, sensitivity was 71.4% and specificity was 75%. VEMPs performed best at detecting SSCD when defining a positive test as oVEMP amplitude >17 μV, with a sensitivity of 68.2%, similar to APT (p > 0.99). The combination of APT and VEMPs increased sensitivity to 88.9%, better than APT alone (p = 0.031) and trending toward better than VEMPs alone (p = 0.063). Conclusions and Relevance: Rhythmic wave patterns on APT are associated with SSCD and may raise suspicion for this condition in conjunction with consistent results on other diagnostic modalities. Although clinical utility requires confirmation in a larger prospective study, APT is a simple, rapid, and widely available tool warranting further study.

Inflammatory Response to Chronic Opioid Exposure in Humans

Objective

In this study, we investigated if chronic opioid exposure leads to changes in immune signaling pathways.

Method

We used phospho-flow cytometry to study intracellular signaling in immune cells of patients with chronic opioid exposure. PBMCs were stimulated with cytokines (IFN-α, IFN-γ, IL-2, IL-6, IL-7, IL-10, IL-21), then stained to analyze 6 lymphocyte subsets and monocytes for phosphorylated STATs (signal transducers and activators of transcription), in particular p-STATs 1, 3 and 5.

Results

After one month of opioid exposure as compared to baseline, IL-2 stimulation of B cells resulted in significantly elevated pSTAT3 levels whereas IFN-γ stimulation resulted in significantly reduced pSTAT5 levels. CD4+ T cell subsets showed reduced pSTAT3 induction in response to multiple cytokine stimuli, and reduced pSTAT1 and pSTAT5 induction with IFN-γ. Similar reductions in pSTAT3 and pSTAT5 induction were seen in CD8+CD45RA+ T cells with several cytokine stimuli. In monocytes, IL-7 and IL-21 stimulation resulted in significantly decreased pSTAT1 levels. No significant changes in pSTAT signaling was found in non-B non-T cells after stimulation with various cytokines. In addition, acute opioid withdrawal via intravenous naloxone resulted in significantly increased pSTAT1 and pSTAT5 levels after IFN-γ stimulation in CD8+ T cells.

Conclusion

One month of opioid exposure significantly reduced cytokine-induced levels of phospho-STAT signaling. These findings suggest that chronic opioid exposure suppresses immune signaling pathways.

Nasal Symptoms Following Laryngectomy: A Cross-sectional Analysis

Background

After total laryngectomy, the severe reduction in nasal airflow alters the function and physiology of the nasal cavity. These anatomic and physiologic changes may in turn impact sinonasal quality of life.

Objective

This study sought to characterize the degree of postoperative sinonasal symptoms experienced by laryngectomees.

Methods

Two groups of subjects were recruited in this cross-sectional analysis: patients who previously underwent laryngectomy with or without chemoradiation for laryngeal or hypopharyngeal cancer and a comparison group treated with radiation but not laryngectomy. Patients underwent assessment of sinonasal symptoms using the Reflective Total Nasal Symptom Score (rTNSS), 22-item Sinonasal Outcome Test (SNOT-22), and visual analog scales (VASs). Patients also underwent nasal endoscopy recorded and graded by blinded reviewers using the Modified Lund–Kennedy (MLK) scale.

Results

Thirty-six laryngectomees and 12 controls were enrolled. The total SNOT-22 was similar between the 2 groups (27.3 vs 20.3, P = .16), but the laryngectomy cohort had higher rhinologic ( P < .01), extranasal ( P = .01), and ear/face ( P = .01) subdomain scores. VAS scores were worse in the laryngectomy group for nasal congestion ( P < .01), rhinorrhea ( P < .01), postnasal drip ( P < .01), and smell ( P < .01) but not for nasal fullness ( P = .11). rTNSS (4.7 vs 2.8, P = .04) and MLK scores (2.8 vs 0.8, P < .01) were higher in the laryngectomy group. In addition, 44% and 83% of patients in the laryngectomy and nonlaryngectomy groups, respectively, subjectively reported well-controlled nasal symptoms.

Conclusion

Laryngectomees are likely to experience a higher degree of subjective and objective nasal disease than nonlaryngectomized patients. Postlaryngectomy nasal dysfunction may be an important aspect of quality of life impairment in the laryngectomee population.

Uncoordinated maturation of developing and regenerating postnatal mammalian vestibular hair cells

Sensory hair cells are mechanoreceptors required for hearing and balance functions. From embryonic development, hair cells acquire apical stereociliary bundles for mechanosensation, basolateral ion channels that shape receptor potential, and synaptic contacts for conveying information centrally. These key maturation steps are sequential and presumed coupled; however, whether hair cells emerging postnatally mature similarly is unknown. Here, we show that in vivo postnatally generated and regenerated hair cells in the utricle, a vestibular organ detecting linear acceleration, acquired some mature somatic features but hair bundles appeared nonfunctional and short. The utricle consists of two hair cell subtypes with distinct morphological, electrophysiological and synaptic features. In both the undamaged and damaged utricle, fate-mapping and electrophysiology experiments showed that Plp1⁺ supporting cells took on type II hair cell properties based on molecular markers, basolateral conductances and synaptic properties yet stereociliary bundles were absent, or small and nonfunctional. By contrast, Lgr5⁺ supporting cells regenerated hair cells with type I and II properties, representing a distinct hair cell precursor subtype. Lastly, direct physiological measurements showed that utricular function abolished by damage was partially regained during regeneration. Together, our data reveal a previously unrecognized aberrant maturation program for hair cells generated and regenerated postnatally and may have broad implications for inner ear regenerative therapies.

During development, sensory hair cells undergo a series of critical maturation steps that are sequential and presumed coupled, but whether regenerated hair cells mature similarly is unknown. This study shows that regenerated vestibular hair cells acquired some mature somatic features, but the apical bundles remained immature.

Presence of Anxiety and Depression Symptoms Affects the First Time Treatment Efficacy and Recurrence of Benign Paroxysmal Positional Vertigo

Objectives

To investigate the possible effects of anxiety and/or depression symptoms on the treatment outcomes and recurrence of benign paroxysmal positional vertigo (BPPV).

Methods

This is a retrospective study conducted at a single institution. 142 consecutive patients diagnosed with idiopathic BPPV at the Department of Otology in Shengjing Hospital of China Medical University between October 2016 and July 2017 were retrospectively reviewed. 127 patients were finally included in this study. Zung self-rating anxiety scale (SAS) and Zung self-rating depression scale (SDS) were used to evaluate the presence of anxiety and/or depression, respectively, in our BPPV patients. A significant score (at or above 50 for SAS and 53 for SDS) represents the presence of clinically significant symptoms. Two-tailed Student’s t-test, χ² test, and logistic regression analysis were used as appropriate. A p value less than 0.05 was considered statistically significant.

Results

The prevalence of anxiety and/or depression symptoms in BPPV patients in the present study was 49.61%. The effectiveness of the first time canalith repositioning maneuver (CRM) was 70.08%. With weekly follow-up treatments of CRM, the success rate increased to 97.64% by 1 month. The total recurrence rate at 6-month follow-up post-cure was 14.17%. Holding all other variables constant, patients with psychiatric symptoms (Relative-risk ratio: 3.160; p = 0.027) and patients with non-posterior semicircular canal (PSC) involvement (Relative-risk ratio: 7.828, p = 0.013) were more likely to experience residual dizziness (RD) even after effective CRM treatment. Psychiatric symptoms (Relative-risk ratio: 6.543; p = 0.001) and female gender (Relative-risk ratio: 4.563; p = 0.010) are risk factors for the failure of first time CRM. In addition, BPPV patients with psychiatric symptoms (Odds ratio: 9.184, p = 0.008) were significantly more likely to experience recurrences within the first 6 months after a successful maneuver.

Conclusion

Anxiety-depression status significantly reduced the efficacy of the first time CRM and increased the risk for recurrence. Other factors, such as female gender and non-PSC involvement are also susceptible risk factors for BPPV patients to require multiple treatments and experience delayed recovery. A screening for psychiatric symptoms in BPPV patients and active treatment of these symptoms would benefit both physicians and patients in understanding and improving the prognosis of the disease and treatment options.

Technological advances shed light on left ventricular cardiac disturbances in cystic fibrosis

Cystic fibrosis (CF), the most common autosomal recessive lethal disease in Caucasians, causes chronic pulmonary disease and can lead to cor pulmonale with right ventricular dysfunction. The presence of the cystic fibrosis transmembrane conductance regulator (CFTR) in cardiac myocardia has prompted debate regarding possible defective ion channel-induced cardiomyopathy. Clinical heart disease in CF is considered rare and is restricted to case reports. It has been unclear if this is due to the lack of physiological importance of CFTR in the heart, the relatively short lifespan of those with CF, or a technical inability to detect subclinical disease. Extensive echocardiographic investigations have yielded contradictory results, leading to the dogma that left ventricular defects in CF occur secondary to lung disease. In this review, we consider why studies examining heart function in CF have not provided clarity on this topic. We then focus on data from new echocardiographic and magnetic resonance imaging technology, which are providing greater insight into cardiac function in CF and demonstrating that, in addition to secondary effects from pulmonary disease, there may be an intrinsic primary defect in the CF heart. With advancing lifespans and activity levels, understanding the risk of cardiac disease is vital to minimizing morbidity in adults with CF.

One Month of Oral Morphine Decreases Gray Matter Volume in the Right Amygdala of Individuals with Low Back Pain: Confirmation of Previously Reported Magnetic Resonance Imaging Results

Objective. Prolonged exposure to opioids is known to produce neuroplastic changes in animals; however, few studies have investigated the effects of short-term prescription opioid use in humans. A previous study from our laboratory demonstrated a dosage-correlated volumetric decrease in the right amygdala of participants administered oral morphine daily for 1 month. The purpose of this current study was to replicate and extend the initial findings.

Methods. Twenty-one participants with chronic low back pain were enrolled in this double-blind, placebo-controlled study. Participants were randomized to receive daily morphine (n = 11) or a matched placebo (n = 10) for 1 month. High-resolution anatomical images were acquired immediately before and after the treatment administration period. Morphological gray matter changes were investigated using tensor-based morphometry, and significant regions were subsequently tested for correlation with morphine dosage.

Results. Decreased gray matter volume was observed in several reward- and pain-related regions in the morphine group, including the bilateral amygdala, left inferior orbitofrontal cortex, and bilateral pre-supplementary motor areas. Morphine administration was also associated with significant gray matter increases in cingulate regions, including the mid cingulate, dorsal anterior cingulate, and ventral posterior cingulate.

Conclusions. Many of the volumetric increases and decreases overlapped spatially with the previously reported changes. Individuals taking placebo for 1 month showed neither gray matter increases nor decreases. The results corroborate previous reports that rapid alterations occur in reward-related networks following short-term prescription opioid use.

Sensory hair cell development and regeneration: similarities and differences

Sensory hair cells are mechanoreceptors of the auditory and vestibular systems and are crucial for hearing and balance. In adult mammals, auditory hair cells are unable to regenerate, and damage to these cells results in permanent hearing loss. By contrast, hair cells in the chick cochlea and the zebrafish lateral line are able to regenerate, prompting studies into the signaling pathways, morphogen gradients and transcription factors that regulate hair cell development and regeneration in various species. Here, we review these findings and discuss how various signaling pathways and factors function to modulate sensory hair cell development and regeneration. By comparing and contrasting development and regeneration, we also highlight the utility and limitations of using defined developmental cues to drive mammalian hair cell regeneration.

Intraoperative acupuncture for posttonsillectomy pain: a randomized, double-blind, placebo-controlled trial

OBJECTIVES/HYPOTHESIS

To evaluate the effect of intraoperative acupuncture on posttonsillectomy pain in the pediatric population.

STUDY DESIGN

Prospective, double-blind, randomized, placebo-controlled trial.

METHODS

Patients aged 3 to 12 years undergoing tonsillectomy were recruited at a tertiary children's hospital between February 2011 and May 2012. Participants were block-randomized to receive acupuncture or sham acupuncture during anesthesia for tonsillectomy. Surgeons, staff, and parents were blinded from treatment. Tonsillectomy was performed by one of two surgeons using a standard technique (monopolar cautery), and a single anesthetic protocol was followed. Study endpoints included time spent in the postanesthesia care unit, the amount of opioids administered in the perioperative period, and pain measures and presence of nausea/vomiting from postoperative home surveys.

RESULTS

Fifty-nine children aged 3 to 12 years were randomized to receive acupuncture (n = 30) or sham acupuncture (n = 29). No significant demographic differences were noted between the two cohorts. Perioperative data were recorded for all patients; 73% of patients later returned home surveys. There were no significant differences in the amount of opioid medications administered or total postanesthesia care unit time between the two cohorts. Home surveys of patients but not of parents revealed significant improvements in pain control in the acupuncture treatment-group postoperatively (P = 0.0065 and 0.051, respectively), and oral intake improved significantly earlier in the acupuncture treatment group (P = 0.01). No adverse effects of acupuncture were reported.

CONCLUSIONS

This study demonstrates that intraoperative acupuncture is feasible, well tolerated, and results in improved pain and earlier return of diet postoperatively.

LEVEL OF EVIDENCE

1b.

Isolating LacZ-expressing cells from mouse inner ear tissues using flow cytometry

Isolation of specific cell types allows one to analyze rare cell populations such as stem/progenitor cells. Such an approach to studying inner ear tissues presents a unique challenge because of the paucity of cells of interest and few transgenic reporter mouse models. Here, we describe a protocol using fluorescence-conjugated probes to selectively label LacZ-positive cells from the neonatal cochleae. The most common underlying pathology of sensorineural hearing loss is the irreversible damage and loss of cochlear sensory hair cells, which are required to transduce sound waves to neural impulses. Recent evidence suggests that the murine auditory and vestibular organs harbor stem/progenitor cells that may have regenerative potential. These findings warrant further investigation, including identifying specific cell types with stem/progenitor cell characteristics. The Wnt signaling pathway has been demonstrated to play a critical role in maintaining stem/progenitor cell populations in several organ systems. We have recently identified Wnt-responsive Axin2-expressing cells in the neonatal cochlea, but their function is largely unknown. To better understand the behavior of these Wnt-responsive cells in vitro, we have developed a method of isolating Axin2-expressing cells from cochleae of Axin2-LacZ reporter mice. Using flow cytometry to isolate Axin2-LacZ positive cells from the neonatal cochleae, we could in turn execute a variety of experiments on live cells to interrogate their behavior as stem/progenitor cells. Here, we describe in detail the steps for the microdissection of neonatal cochlea, dissociation of these tissues, labeling of the LacZ-positive cells using a fluorogenic substrate, and cell sorting. Techniques for dissociating cochleae into single cells and isolating cochlear cells via flow cytometry have been described. We have made modifications to these techniques to establish a novel protocol to isolate LacZ-expressing cells from the neonatal cochlea.