Improvement of metabolic control does not normalize auditory brainstem latencies in subjects with insulin-dependent diabetes mellitus

Diabetes-induced auditory complications: are they preventable? a comprehensive review of interventions

Diabetes mellitus is a chronic metabolic disorder characterized by elevated blood glucose levels, which, over time, lead to major chronic complications in various organs of the body. A growing body of research suggests that diabetes could also result in degenerative changes in the auditory system. To date, several attempts have been made to prevent and reduce diabetes-induced auditory complications. Such attempts have generally focused on disease modifying as well as other pharmacological treatments involving several herbal and non-herbal agents such as vitamins C and E, rutin, resveratrol, coffee, trigonelline, Dioscorea nipponica, red ginseng, Pterostilbene Bofutsushosan, Daisaikoto, tolrestat, ACE inhibitors (enalapril), Ca antagonists (nimodipine), Lipo-prostaglandin E1, methylprednisolone, dexamethasone, and chlorogenic acid and also other strategies like acupuncture. However, there is no consensus about which are the most effective strategies for preventing and reducing auditory complications in diabetic patients with few side effects and maximum efficacy. This paper provides a comprehensive review of interventions for preventing and treating diabetes-induced auditory complications to help therapists.

Cochlear, auditory brainstem responses in Type 1 diabetes: relationship with metabolic variables and diabetic complications

AIMS

Few studies have analysed the presence of hearing abnormalities in diabetes. We assessed the presence of subclinical auditory alterations and their possible association with early vascular and neurological dysfunction in young adults with Type 1 diabetes of long duration.

METHODS

Thirty-one patients with Type 1 diabetes (mean age 33 ± 2.3 years, disease duration 25.7 ± 4.2 years) and 10 healthy controls underwent pure tone audiometry (PTA), distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) analyses. Associations with metabolic variables and chronic complications were explored.

RESULTS

Compared with healthy controls, patients with diabetes had significantly higher mean hearing thresholds, although still within the normoacusic range. DPOAE intensities at medium frequencies (2.8-4 kHz) were significantly lower in patients with diabetes. In ABR, in addition to waves I, III and V, we observed the appearance of a visible wave IV in patients with diabetes compared with controls (prevalence 61% vs. 10%, P < 0.05), and its appearance was related to a prolonged I-V interval (4.40 ± 0.62 ms vs. 4.19 ± 0.58 ms, P < 0.05). Diastolic blood pressure was higher in people with abnormal DPOAE (P < 0.05), whereas systolic blood pressure correlated with wave V and interpeak I-V interval latencies. A trend towards an association between evidence of wave IV and the presence of somatic neuropathy or abnormal cardiovascular autonomic tests was observed.

CONCLUSIONS

Young adults with long-term Type 1 diabetes have subclinical abnormalities in qualitative auditory perception, despite normal hearing thresholds, which might reflect neuropathic and/or vascular alterations.

Factors affecting postoperative cerebrospinal fluid leaks after retrosigmoidal craniotomy for vestibular schwannomas

Object

The aim of this study was to identify patients likely to develop CSF leaks after vestibular schwannoma surgery using a retrospective analysis for the identification of risk factors.

Methods

Between January 2001 and December 2006, 420 patients underwent retrosigmoidal microsurgical tumor removal in a standardized procedure. Of these 420 patients, 363 underwent treatment for the first time, and 27 suffered from recurrent tumors. Twenty-six patients had bilateral tumors due to neurofibromatosis Type 2, and 4 patients had previously undergone radiosurgical treatment. An analysis was performed to examine the incidence of postoperative CSF fistulas in all 4 groups.

Results

The incidence of CSF leakage was higher in the tumor recurrence group (11.1%) than in patients undergoing surgery for the first time (4.4%). There were no CSF fistulas in the neurofibromatosis Type 2 group or in patients with preoperative radiosurgical treatment. Tumor size was identified as a possible risk factor in a previous study.

Conclusions

Surgery for recurrent tumors is a significant risk factor for the development of CSF leaks.

Auditory brainstem evoked responses in insulin-dependent (ID) and non-insulin-dependent (NID) diabetic subjects with normal hearing

Hearing impairment has been reported to be one of the late complications of diabetes mellitus (DM), and the frequency varies. Previous data suggest that auditory brainstem potentials deteriorate long before the hearing impairment appears in patients with DM. Delay in neural conductance along the auditory pathway due to DM was assessed by means of auditory brainstem response (ABR) in 43 patients with normal hearing in a controlled study. Patients were classified according to age, presence of neuropathy. metabolic control, and duration and type of DM. ABR recordings revealed that absolute latencies of waves I, III and V were prolonged significantly in the diabetic group when compared to the control group (p < 0.05). When two diabetic groups (insulin-dependent and non-insulin-dependent) were compared with each other, the difference between the latency of wave I and the inter-peak latencies of I-III, III-V and I-V was not significant (p > 0.05). However, the difference between the latencies of waves III and V in the two diabetic groups was statistically significant. The duration of diabetes, blood glucose level and age were not associated with prolonged ABR latencies (p > 0.05). Prolongation of latency of ABR in patients with DM should alert us to possible damage to the auditory nerve, and close follow-up is needed in these patients.

Diagnosis of sub-clinical hepatic encephalopathy by Neuropsychological Tests (NP-tests)

AIM

At present, there are no generally accepted diagnostic criteria or methods for sub-clinical hepatic encephalopathy (SHE) associated with liver cirrhosis. We therefore developed an easily conducted computer-aided quantitative neuropsychological function test system for use in routine medical practice.

METHODS

The system was used prepare basic values according to age in 542 healthy subjects, and the results were compared with 292 liver cirrhosis patients. The software is composed of eight tests: NCT-A, NCT-B, Figure Design Test, Digit Symbol Test, Block Design Test, and the Reaction Time-A, Reaction Time-B, and Reaction Time-C.

RESULTS

Performance time is approximately 15 to 20 min. There is no need to select a specific test location and it is convenient to use even without a professional examiner. When the top and bottom 10%, which correspond to the outlier values statistically in the healthy subjects, were used as the cutoff values abnormal results were observed in approximately 25% of the liver cirrhosis patients. Moreover, 58% of the patients had abnormal values according to the results of at least one of the tests.

CONCLUSION

It is expected that this test will be used to further assess the diagnosis and pathology of SHE and that it will be utilized as a routine method of diagnosis.

Does Packing the Eustachian Tube Impact Cerebrospin al Fluid Rhinorrhea Rates in Translabyrinthine Vestibular Schwannoma Resections?

OBJECTIVE

To calculate cerebrospinal fluid (CSF) leak rates for translabyrinthine (TL), middle cranial fossa (MCF), and retrosigmoid/suboccipital (SO) craniotomies performed for removal of vestibular schwannoma (VS) and analyze whether packing the eustachian tube (ET) in TL VS resections impacts CSF rhinorrhea rates.

STUDY DESIGN

Retrospective.

SETTING

Tertiary care center.

METHODS

Chart review.

RESULTS

Three hundred fifty-nine VS resections were reviewed in 356 patients ranging from 10 to 86 years of age. Two hundred thirty-one TL, 70 MCF, 53 SO, and 5 combined TL/SO procedures were analyzed. Total CSF leak rates (incisional, otorrhea, and rhinorrhea) were 14.2% for TL, 11.4% for MCF, and 13.2% for SO approaches. Differences in overall CSF leak rates were not statistically significant. For those who underwent TL craniotomies, 2 groups of patients were identified based on whether their ETs were packed during surgery. In 1 group, the incus was removed, the aditus enlarged, the ET packed, and the middle ear filled with muscle. In the second group, the aditus, epitympanum and middle ear were packed without removing the incus, and the ET was not packed. Of 148 patients who had their ET packed, 12 developed CSF rhinorrhea (8.1%). The CSF rhinorrhea rate for patients who did not have ET packing was 5.9% (3 of 51 patients). This difference was not statistically significant (p = 0.80). When Proplast was used to pack the ET (121 patients), the CSF rhinorrhea rate was 5.8%. Unfortunately, this material extruded in 4 of 121 patients (3.3%) and presented clinically as delayed purulent otorrhea.

CONCLUSION

Cerebrospinal fluid leak rates were similar in patients undergoing TL, SO, and MCF approaches, and CSF rhinorrhea was not decreased by ET packing. Patients whose ETs are packed with Proplast are at risk for extrusion and otorrhea years after their initial VS resection.

Safety and efficacy of a novel polyethylene glycol hydrogel sealant for watertight dural repair

Object

The authors prospectively evaluated the safety and efficacy of a novel polyethylene glycol (PEG) hydrogel sealant in patients undergoing elective cranial surgery with documented cerebrospinal fluid (CSF) leakage after sutured dural repair.

Methods

The PEG hydrogel sealant was used at 11 different study sites in 111 patients with documented intraoperative CSF leakage after neurosurgical dural repair for a variety of conditions. Intraoperative CSF leakage was either spontaneous or induced by a Valsalva maneuver. Patients were monitored for 3 months postoperatively with physical examinations, clinical laboratory analyses, and diagnostic imaging.

The PEG hydrogel sealant was 100% effective in stopping CSF leakage in all patients. There were no sealant-related adverse events and all clinical outcomes were consistent with expectations for seriously ill patients undergoing prolonged neurosurgical procedures.

Conclusions

The PEG hydrogel sealant provides a safe and effective watertight closure when used as an adjunct to sutured dural repair during cranial surgery.

Neurophysiological investigation of hepatic encephalopathy

The neurophysiological tools used to study hepatic encephalopathy (HE) are the electroencephalogram (EEG) and the evoked potentials (EPs), both exogenous and endogenous. These tools are used (1) to diagnose HE in patients with severe liver disease and mental alteration, (2) to grade overt HE and monitor the effect of treatment for HE, (3) to diagnose minimal HE (4) to predict the occurrence of episodes of overt HE or liver-related death. The rationale for the use of each of these tools together with their theoretical and practical role is reviewed.

Characteristics of minimal hepatic encephalopathy

The term minimal hepatic encephalopathy refers to the subtle changes in cognitive function, electrophysiological parameters, cerebral neurochemical/neurotransmitter homeostasis, cerebral blood flow, metabolism, and fluid homeostasis that can be observed in patients with cirrhosis who have no clinical evidence of hepatic encephalopathy. Use of this term emphasizes the fact that the entity of hepatic encephalopathy is a single syndrome with quantitatively distinct features relating to severity. The absence of clinical evidence of hepatic encephalopathy is key to the diagnosis and can only be determined by a detailed assessment of the patients' history and a comprehensive neurological assessment of consciousness, cognitive, and motor function. The neuropsychological features of minimal hepatic encephalopathy point to a disorder of executive functioning, particularly selective attention and psychomotor speed, but other abnormalities may be observed. Alterations in electrophysiological variables have been described; endogenous evoked potentials are, in principle, more likely to reflect the presence of minimal hepatic encephalopathy, since they reflect cognitive phenomena rather than mere stimulus conduction but the specificity of the changes observed is unclear at present. Changes have also been described in the execution of diadochokinetic movements and in the capacity to discriminate flickering light, both of which may have diagnostic potential. The changes observed in cerebral blood flow and metabolism in SPET, PET, and 1H and 31P MRS studies reflect the pathogenic process that underlies the condition rather than providing diagnostic information. Similarly, the morphological brain abnormalities identified in this population, including mild brain oedema, hyperintensity of the globus pallidus and other subcortical nuclei observed in cerebral MR studies, and the central and cortical atrophy observed in neural imaging studies, are unlikely to have diagnostic utility. The presence of minimal hepatic encephalopathy is not without clinical consequence; it has a detrimental effect on health-related quality of life, the ability to perform complex tasks such as driving, and on outcome.

The Incidence of Cerebrospinal Fluid Leak after Vestibular Schwannoma Surgery

OBJECTIVE

To review the incidence of cerebrospinal fluid leak after vestibular schwannoma removal reported in the literature.

DATA SOURCES

MEDLINE and PubMed literature search using the terms "acoustic neuroma" or "vestibular schwannoma," and "cerebrospinal fluid leak" or "cerebrospinal fluid fistula" covering the period from 1985 to the present in the English language literature. A review of bibliographies of these studies was also performed.

STUDY SELECTION

Criteria for inclusion in this meta-analysis consisted of the availability of extractable data from studies presenting a defined group of patients who had undergone primary vestibular schwannoma removal and for whom the presence and absence of cerebrospinal fluid leakage was reported. Studies reporting combined approaches were excluded. No duplications of patient populations were included. Twenty-five studies met the inclusion criteria.

DATA EXTRACTION

Quality of the studies was determined by the design of each study and the ability to combine the data with the results of other studies. All of the studies were biased by their retrospective, nonrandomized nature.

DATA SYNTHESIS

Significance (p < 0.05) was determined using the chi2 test.

CONCLUSIONS

Cerebrospinal fluid leak occurred in 10.6% of 2,273 retrosigmoid surgeries, 9.5% of 3,118 translabyrinthine surgeries, and 10.6% of 573 middle fossa surgeries. The type of cerebrospinal fluid leak was not associated with surgical approach. Meningitis was significantly associated with cerebrospinal fluid leak (p < 0.05). Age and tumor size were not associated with cerebrospinal fluid leak.

Cerebrospinal fluid leak after acoustic neuroma surgery: a comparison of the translabyrinthine, middle fossa, and retrosigmoid approaches

OBJECTIVE

To determine whether the choice of surgical approach affects the rate of postoperative cerebrospinal fluid leakage in patients who have undergone surgical resection of acoustic neuroma.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary referral center.

PATIENTS

Three hundred patients who underwent surgery for acoustic neuromas were selected by consecutive medical record number until 100 resections via each surgical approach (translabyrinthine, middle fossa, and retrosigmoid) had been gathered.

MAIN OUTCOME MEASURES

Surgical approach used, cerebrospinal fluid leak incidence, tumor size, patient age.

RESULTS

Postoperative cerebrospinal fluid leak of any severity was observed in 13% of translabyrinthine, 10% of middle fossa, and 10% of retrosigmoid patients. These difference in the rate of cerebrospinal fluid leakage were not statistically significant (p = 0.82). The majority of leaks were managed conservatively with fluid and activity restriction, often accompanied by a period of lumbar subarachnoid drainage. There was a need to return to the operating room for a definitive procedure in 4% of translabyrinthine, 2% of middle fossa, and 3% retrosigmoid patients; again not statistically different among the approaches (p = 0.43). Tumor size was not correlated with cerebrospinal fluid leak rate (p = 0.13). Patient age, for patients older than 50 years, was suggestive of increased odds of cerebrospinal fluid leak (p = 0.06).

CONCLUSION

Neither surgical approach nor tumor size affects the rate of postoperative cerebrospinal fluid leakage or the necessity of managing a leak with a return to the operating room. Cerebrospinal fluid leakage rates have remained stable in recent decades despite numerous innovative attempts to improve dural closure, seal transected air cell tracts, and occlude anatomic pathways. The finding that leak rates were similar among three dissimilar surgical techniques suggests that factors other than techniques of wound closure, such as transient postoperative rises in cerebrospinal fluid pressure, may be responsible for these recalcitrant cases.

Cerebrospinal fluid leak after acoustic neuroma surgery: influence of tumor size and surgical approach on incidence and response to treatment

OBJECT

The aims of this study were to review the incidence of cerebrospinal fluid (CSF) leakage complicating the removal of acoustic neuroma and to identify factors that influence its occurrence and treatment.

METHODS

Prospective information on consecutive patients who underwent operation for acoustic neuroma was supplemented by a retrospective review of the medical records in which patients with CSF leaks complicating tumor removal were identified. This paper represents a continuation of a previously published series and thus compiles the authors' continuous experience over the last 24 years of practice. In 624 cases of acoustic neuroma the authors observed an overall incidence of 10.7% for CSF leak. The rate of leakage was significantly lower in the last 9 years compared with the first 15, most likely because of the abandonment of the combined translabyrinthine (TL)-middle fossa exposure. There was no difference in the leakage rate between TL and retrosigmoid (RS) approaches, although there were differences in the site of the leak (wound leaks occurred more frequently after a TL and otorrhea after an RS approach, respectively). Tumor size (maximum extracanalicular diameter) had a significant effect on the leakage rate overall and for RS but not for TL procedures. The majority of leaks ceased with nonsurgical treatments (18% with expectant management and 49% with lumbar CSF drainage). However, TL leaks (especially rhinorrhea) required surgical repair significantly more often than RS leaks. This has not been reported previously.

CONCLUSIONS

The rate of CSF leakage after TL and RS procedures has remained stable. Factors influencing its occurrence include tumor size but not surgical approach. The TL-related leaks had a significantly higher surgical repair rate than RS-related leaks, an additional factor to consider when choosing an approach. The problem of CSF leakage becomes increasingly important as nonsurgical treatments for acoustic neuroma are developed.

Use of the auditory brainstem response testing in the clinical evaluation of the patients with diabetes mellitus

The objective of the study was to assess whether a relationship exists between the auditory brain stem response (ABR) results and diabetes mellitus with and without complications. In the clinical and audiometry laboratory settings, diabetic patients with and without complications (retinopathy and/or nephropathy) were examined using ABR testing, and the results were interpreted for their applicability in clinical practice. Fifty-nine patients with diabetic retinopathy or nephropathy (study group) and 20 diabetic patients without any known diabetic complication (control group) were assessed with audiometry and ABR testing. ABR revealed that the absolute latencies and interwave intervals of the waves I through V were prolonged significantly in the study group when compared to the control group. The amplitudes of waves I through V were diminished in the study group when compared to the control group, but a statistical significance was present only for wave V amplitude. Quantitative (wave I to wave V amplitude ratio) and qualitative analyses of the ABR waves showed abnormal waveforms in the study and control groups by 55.2 and 27.6%, respectively. There is a brain stem neuropathy in diabetes mellitus which can be assessed with ABR testing. The likelihood of encountering a diabetic complication increases as the ABR results become abnormal.