Ceruminolytic efficacy in adults versus children

Analysis of the Microbiome of the Ear Canal in Normal Individuals and Patients with Chronic Otitis Externa

BACKGROUND

Recently, microbiome research has been actively conducted for various skin areas. However, no study has yet compared the microbiome of bacteria and fungi in the ear canal of healthy individuals and patients with chronic otitis externa in Korea.

OBJECTIVE

This study aimed to investigate the difference in the distribution of fungal and bacterial microbial communities in ear canal samples of healthy individuals and patients with chronic otitis externa.

METHODS

In 24 patients with bilateral chronic otitis externa and 24 healthy controls, cotton swabs were used to obtain samples from the bilateral ear canal. To characterize the fungal and bacterial communities, we sequenced and analyzed the 16S rRNA V4-V5 and ITS1 regions using Quantitative Insights into Microbial Ecology 2, respectively.

RESULTS

The alpha diversity analysis for bacteria and fungi confirmed that both richness and evenness decreased in the patient group. The beta diversity analysis for bacteria confirmed that these parameters differed between the control and patient groups. The beta diversity analysis for fungi showed no difference between the groups.

CONCLUSION

We observed different skin microbiomes in the patients with chronic otitis externa compared with those in the healthy individuals.

[Microbiome of the external auditory canal and preoperative preparation of patients in otosurgery (literature review)]

OBJECTIVE

To analyze the effectiveness of methods of antiseptic and hygienic preoperative preparation of the operating field in otosurgery.

MATERIAL AND METHODS

A review and an expert assessment of the corresponding research objectives of scientific publications contained in the PubMed and Google Scholar databases have been carried out.

RESULTS

Various studies indicate a lower ototoxicity of 5-10% of the drug povidone-iodine compared to others. Drugs, such as Miramistin, Okomistin, Dioxidine, are actively used in otiatrics in Russia, but no data on their ototoxicity have been noted. The collected data point to the relevance and prospects of studying the microbiome of the external auditory canal, assessing its effect on the course of the postoperative period, depending on various methods of preparation (antiseptic, removal of earwax and hair depilation) of the surgical field for otosurgery.

Cerumen Management: An Updated Clinical Review and Evidence-Based Approach for Primary Care Physicians

Objective: To provide family physicians with a practical, evidence-based approach to managing patients with cerumen impaction. Methods: MEDLINE, The Cochrane Library, and the Turning Research Into Practice (TRIP) database were searched for English-language cerumen impaction guidelines and reviews. All such articles published between 1992 and 2018 were reviewed, with most providing level II and III evidence. Results: Cerumen impaction is a common presentation seen in primary care and cerumen removal is one of the most common otolaryngologic procedures performed in general practice. Cerumen impaction is often harmless but can be accompanied by more serious symptoms. Cerumenolytics and irrigation of the ear canal are reasonable first-line therapies and can be used in conjunction or isolation. If irrigation and cerumenolytics are contraindicated, manual removal is appropriate, but the tools necessary are not commonplace in primary care clinics and specialized training may be required to prevent adverse outcomes. Conclusion: Family physicians play a key role in the assessment and management of cerumen impaction and are well equipped to do so. Knowledge of the available techniques for cerumen removal as well as their contraindications ensures that cerumen is removed safely and effectively. When cerumen removal cannot be removed safely in a primary care setting, referral to Otolaryngology-Head and Neck Surgery is appropriate.

Cerumenolytics with or without manual extraction for impacted earwax: A network meta-analysis of randomised clinical trials

BACKGROUND

Many different substances for cerumenolysis have been evaluated in clinical trials. We carried out a systematic review and network meta-analysis to compare their effectiveness.

METHODS

Electronic databases were searched for randomised clinical trials conducted in patients with impacted cerumen evaluating cerumenolytics. The primary outcome was the proportion of patients with wax clearance using manual techniques. Rankogram plot was used to assess the "best" cerumenolytic. Odds ratio (OR) with 95% confidence intervals (95% CI) was the effect estimate.

RESULTS

Twenty-six studies were included in the systematic review and 25 in the meta-analysis. Sodium bicarbonate (OR: 2.68, 95% CI: 1.2, 6.1) and paradichlorobenzene (OR: 30.9, 95% CI: 5.9, 161.3) were associated with significantly greater proportions of patients with wax clearance following syringing compared to normal saline. Rankogram plot revealed paradichlorobenzene to have the highest probability of being the "best" cerumenolytic. Chlorobutanol was observed to be significantly better than normal saline in adults as well as following single application. Following multiple applications, glycerol, docusate sodium, hydrogen peroxide, oil, paradichlorobenzene, hydrogen peroxide/glycerol and arachis oil/chlorobutanol/paradichlorobenzene were observed with significant cerumenolytic activities. Urea/hydrogen peroxide/glycerol was observed with a significant cerumenolytic activity without the need for further interventions such as syringing/aspiration/suction.

CONCLUSION

We observed several cerumenolytics to be effective in the treatment of impacted earwax when accompanied by additional manual techniques such as syringing/aspiration/suction.

Ear drops for the removal of ear wax

BACKGROUND

Ear wax (cerumen) is a normal bodily secretion that can become a problem when it obstructs the ear canal. Symptoms attributed to wax (such as deafness and pain) are among the commonest reasons for patients to present to primary care with ear trouble.Wax is part of the ear's self-cleaning mechanism and is usually naturally expelled from the ear canal without causing problems. When this mechanism fails, wax is retained in the canal and may become impacted; interventions to encourage its removal may then be needed. Application of ear drops is one of these methods. Liquids used to remove and soften wax are of several kinds: oil-based compounds (e.g. olive or almond oil); water-based compounds (e.g. sodium bicarbonate or water itself); a combination of the above or non-water, non-oil-based solutions, such as carbamide peroxide (a hydrogen peroxide-urea compound) and glycerol.

OBJECTIVES

To assess the effects of ear drops (or sprays) to remove or aid the removal of ear wax in adults and children.

SEARCH METHODS

We searched the Cochrane ENT Trials Register; Cochrane Register of Studies; PubMed; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the most recent search was 23 March 2018.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in which a 'cerumenolytic' was compared with no treatment, water or saline, an alternative liquid treatment (oil or almond oil) or another 'cerumenolytic' in adults or children with obstructing or impacted ear wax.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane. The primary outcomes were 1) the proportion of patients (or ears) with complete clearance of ear wax and 2) adverse effects (discomfort, irritation or pain). Secondary outcomes were: extent of wax clearance; proportion of people (or ears) with relief of symptoms due to wax; proportion of people (or ears) requiring further intervention to remove wax; success of mechanical removal of residual wax following treatment; any other adverse effects recorded and cost. We used GRADE to assess the quality of the evidence for each outcome; this is indicated in italics.

MAIN RESULTS

We included 10 studies, with 623 participants (900 ears). Interventions included: oil-based treatments (triethanolamine polypeptide, almond oil, benzocaine, chlorobutanol), water-based treatments (docusate sodium, carbamide peroxide, phenazone, choline salicylate, urea peroxide, potassium carbonate), other active comparators (e.g. saline or water alone) and no treatment. Nine of the studies were more than 15 years old.The overall risk of bias across the 10 included studies was low or unclear.

PRIMARY OUTCOME

proportion of patients (or ears) with complete clearance of ear waxSix studies (360 participants; 491 ears) contributed quantitative data and were included in our meta-analyses.Active treatment versus no treatmentOnly one study addressed this comparison. The proportion of ears with complete clearance of ear wax was higher in the active treatment group (22%) compared with the no treatment group (5%) after five days of treatment (risk ratio (RR) 4.09, 95% confidence interval (CI) 1.00 to 16.80); one study; 117 ears; NNTB = 8) (low-quality evidence).Active treatment versus water or salineWe found no evidence of a difference in the proportion of patients (or ears) with complete clearance of ear wax when the active treatment group was compared to the water or saline group (RR 1.47, 95% CI 0.79 to 2.75; three studies; 213 participants; 257 ears) (low-quality evidence). Two studies applied drops for five days, but one study only applied the drops for 15 minutes. When we excluded this study in a sensitivity analysis it did not change the result.Water or saline versus no treatmentThis comparison was only addressed in the single study cited above (active versus no treatment) and there was no evidence of a difference in the proportion of ears with complete wax clearance when comparing water or saline with no treatment after five days of treatment (RR 4.00, 95% CI 0.91 to 17.62; one study; 76 ears) (low-quality evidence).Active treatment A versus active treatment BSeveral single studies evaluated 'head-to-head' comparisons between two active treatments. We found no evidence to show that one was superior to any other.Subgroup analysis of oil-based active treatments versus non-oil based active treatmentsWe found no evidence of a difference in this outcome when oil-based treatments were compared with non-oil-based active treatments.

PRIMARY OUTCOME

adverse effects: discomfort, irritation or painOnly seven studies planned to measure and did report this outcome. Only two (141 participants;176 ears) provided useable data. There was no evidence of a significant difference in the number of adverse effects between the types of ear drops in these two studies. We summarised the remaining five studies narratively. All events were mild and reported in fewer than 30 participants across the seven studies (low-quality evidence).Secondary outcomesThree studies reported 'other' adverse effects (how many studies planned to report these is unclear). The available information was limited and included occasional reports of dizziness, unpleasant smell, tinnitus and hearing loss. No significant differences between groups were reported. There were no emergencies or serious adverse effects reported in any of the 10 studies.There was very limited or no information available on our remaining secondary outcomes.

AUTHORS' CONCLUSIONS

Although a number of studies aimed to evaluate whether or not one type of cerumenolytic is more effective than another, there is no high-quality evidence to allow a firm conclusion to be drawn and the answer remains uncertain.A single study suggests that applying ear drops for five days may result in a greater likelihood of complete wax clearance than no treatment at all. However, we cannot conclude whether one type of active treatment is more effective than another and there was no evidence of a difference in efficacy between oil-based and water-based active treatments.There is no evidence to show that using saline or water alone is better or worse than commercially produced cerumenolytics. Equally, there is also no evidence to show that using saline or water alone is better than no treatment.

WITHDRAWN: Ear drops for the removal of ear wax

BACKGROUND

Problems attributed to the accumulation of wax (cerumen) are among the most common reasons for people to present to their general practitioners with ear trouble. Treatment for this condition often involves use of a wax softening agent (cerumenolytic) to disperse the cerumen, reduce the need for, or facilitate syringing, but there is no consensus on the effectiveness of the variety of cerumenolytics in use.

OBJECTIVES

To assess the effectiveness of ear drops (cerumenolytics) for the removal of symptomatic ear wax.

SEARCH METHODS

We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2008 issue 2); MEDLINE; EMBASE; CINAHL; ISI Proceedings; Cambridge Scientific Abstracts; mRCT and additional sources for published and unpublished trials. The date of the most recent search was April 2008.

SELECTION CRITERIA

We identified all randomised controlled trials in which a cerumenolytic was compared with no treatment, a placebo, or other cerumenolytics in participants with obstructing or impacted ear wax, and in which the proportion of participants with sufficient clearance of the external canal to make further mechanical clearance unnecessary (primary outcome measure) was stated or calculable.

DATA COLLECTION AND ANALYSIS

The two authors reviewed all the retrieved trials and applied the inclusion criteria independently.

MAIN RESULTS

Nine trials satisfied the inclusion criteria. In all, 679 participants received one of 11 different cerumenolytics. One trial compared active treatments with no treatment, three compared active treatments with water or a saline 'placebo', and all nine trials compared two or more active treatments. Eight trials included syringing as a secondary intervention.Overall, results were inconclusive. The majority of comparisons showed no difference between treatments.  Meta-analysis of two high quality trials produced a statistical difference in favour of triethanolamine polypeptide over saline in preventing the need for syringing, but no other significant differences between treatments.In three trials of high to moderate quality, no difference was found between the effectiveness of either sodium bicarbonate ear drops, chlorbutanol, triethanolamine polypeptide oleate condensate or docusate sodium liquid versus a sterile water or saline 'placebo'.One trial of moderate methodological quality found all three treatments - sodium bicarbonate ear drops, chlorbutanol and sterile water - to be significantly better than no treatment at preventing the need for syringing.None of the higher quality trials demonstrated superiority of one agent over another in direct comparisons.

AUTHORS' CONCLUSIONS

Trials have been heterogeneous and generally of low or moderate quality, making it difficult to offer any definitive recommendations on the effectiveness of cerumenolytics for the removal of symptomatic ear wax. Using drops of any sort appears to be better than no treatment, but it is uncertain if one type of drop is any better than another. Future trials should be of high methodological quality, have large sample sizes, and compare both oil-based and water-based solvents with placebo, no treatment or both.

Evaluation of the safety and efficacy of a novel product for the removal of impacted human cerumen

Background

This open-label study evaluated the safety and efficacy of a novel product for the removal of impacted cerumen in adult patients.

Methods

This was a prospective, single-center, single-arm, self-controlled clinical trial conducted in a community general practice setting. The novel product contains glycolic acid in an otologically-acceptable buffer containing sodium bicarbonate and glycerin and other buffering agents. The product was instilled into the ear canal prior to irrigation with warm water. Severity of cerumen impaction was graded using a 5-point scale. Improvement in tympanic membrane visualization was assessed after instillation and irrigation.

Results

A majority (83%, 25/30) of ears showed improvement with one application: with 53% (16/30) totally dissolved and gained 100% TM visualization. Total dissolution was observed in 80% (24/30) of the study ears per the intent-to-treat analysis and 86% (24/28) if irrigation instructions were followed. Most of the ears/participants that had cerumen blockage symptoms experienced significant improvement with the application. Feelings of fullness disappeared in 92% (11/12) of the affected ears; ears itching, 91% (10/11); water trapping or cracking, 78%, and decreased hearing disappeared in 71% (10/14). All (100%, 18) of the participants who completed the application satisfaction assessment were satisfied with the application process in terms of time needed and the overall rinse procedure. Only one mild adverse event (ear pruritis) occurred that was related to application.

Conclusions

The tested cerumen removal product was effective and safe for removing moderate to severe blockage in patients with impacted cerumen. Procedure satisfaction for the product was high.

Trial Registration

This trial is registered on http://www.clinicaltrials.gov/. The registration number is NCT02829294. The trial was retrospectively registered on July 8, 2016.

A new approach for cerumenolytic treatment in children: In vivo and in vitro study

OBJECTIVES

To demonstrate the effects of various cerumenolytic solutions in vivo and in vitro and to measure the change in pain following treatment.

METHODS

The study was done as a single-centre, prospective and double-blind study. Among 1243 paediatric patients with total or nearly total occlusive plug in 4 years period, those who accepted endoscopic ear examination and cleaning via aspiration after a follow-up period of at least 10 days following treatment were included in the study. Day of total TM visualisation was noted and removal co-efficient was calculated. The pre and post-treatment pain levels of the patients were assessed using analogue chromatic continuous scale (ACCS). In the in vitro part, cerumen samples collected at equal amounts from 20 patients were treated at 36-400°C in 6 different tubes with the same solutions and their dissolution degrees were assessed over a period of 5 days (Hour 6, Hour 12, Hour 48, Hour 72, Hour 92, Hour 120). Additionally, the degree of resolution in the tube treated with distilled water was considered to be the control reference.

RESULTS

In the in vivo part of the study, total TM visualisation was observed in Group 1 at 50.2% (Day 3), in Group at 57.1%, in Group at 62.3%, in Group at 44.3% and in Group 5 at 73.5%. The group with the lowest removal co-efficient was Group 5 (removal co-efficient=1.623). In reference to the ACCS pain scores of the patients, the intra-group change pre-post treatment was found statistically significant for all groups (p=0.008; p=0.0222; p=0.005; p=0.026; p=0.018). After statistical analysis between the groups the difference between Group 5 and other groups was found statistically significant (p=0.002; p=0.026; p=0.044; p=0.034). In the in vitro part of the study, the best dissolution was observed in Group 2.

CONCLUSIONS

In our study, the best cerumenolytic solutions were identified to be glycerine 10cc+3% hydrogen peroxide 10cc+10% sodium bicarbonate 10cc+distilled water 10cc. Especially the use of this mixture ease in terms of pain for the patient and in terms of time and comfort for the physician during the removal procedure.

A comparative study of ceruminolytic agents

A prospective study was done to access the efficacy of ceruminolytic agents, i.e 2% paradichlorobenzene, 10% sodium bicarbonate, 2.5% acetic acid and normal saline. All score 4 hard impacted ear wax cases in the adult population (>20 years) were accrued for the assessment of the relative efficacy. Upon analyzing the comparative efficacy of four ceruminolytic agents, by taking into consideration three parameters (post) ceruminolytic cerumen score, attempts of syringing required to extrude the cerumen mass, post-ceruminolytic use and appearance of the removed cerumen mass. 2% paradichlorobenzene emerged as the most superior ceruminolytic, closely followed by 10% sodium bicarbonate. 2.5% acetic acid fared moderately while normal saline emerged as the least efficacious ceruminolytic agent.

Ear drops for the removal of ear wax

BACKGROUND

Problems attributed to the accumulation of wax (cerumen) are among the most common reasons for people to present to their general practitioners with ear trouble. Treatment for this condition often involves use of a wax softening agent (cerumenolytic) to disperse the cerumen, reduce the need for, or facilitate syringing, but there is no consensus on the effectiveness of the variety of cerumenolytics in use.

OBJECTIVES

To assess the effectiveness of ear drops (cerumenolytics) for the removal of symptomatic ear wax.

SEARCH STRATEGY

We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2008 issue 2); MEDLINE; EMBASE; CINAHL; ISI Proceedings; Cambridge Scientific Abstracts; mRCT and additional sources for published and unpublished trials. The date of the most recent search was April 2008.

SELECTION CRITERIA

We identified all randomised controlled trials in which a cerumenolytic was compared with no treatment, a placebo, or other cerumenolytics in participants with obstructing or impacted ear wax, and in which the proportion of participants with sufficient clearance of the external canal to make further mechanical clearance unnecessary (primary outcome measure) was stated or calculable.

DATA COLLECTION AND ANALYSIS

The two authors reviewed all the retrieved trials and applied the inclusion criteria independently.

MAIN RESULTS

Nine trials satisfied the inclusion criteria. In all, 679 participants received one of 11 different cerumenolytics. One trial compared active treatments with no treatment, three compared active treatments with water or a saline 'placebo', and all nine trials compared two or more active treatments. Eight trials included syringing as a secondary intervention.Overall, results were inconclusive. The majority of comparisons showed no difference between treatments. Meta-analysis of two high quality trials produced a statistical difference in favour of triethanolamine polypeptide over saline in preventing the need for syringing, but no other significant differences between treatments.In three trials of high to moderate quality, no difference was found between the effectiveness of either sodium bicarbonate ear drops, chlorbutanol, triethanolamine polypeptide oleate condensate or docusate sodium liquid versus a sterile water or saline 'placebo'.One trial of moderate methodological quality found all three treatments - sodium bicarbonate ear drops, chlorbutanol and sterile water - to be significantly better than no treatment at preventing the need for syringing.None of the higher quality trials demonstrated superiority of one agent over another in direct comparisons.

AUTHORS' CONCLUSIONS

Trials have been heterogeneous and generally of low or moderate quality, making it difficult to offer any definitive recommendations on the effectiveness of cerumenolytics for the removal of symptomatic ear wax. Using drops of any sort appears to be better than no treatment, but it is uncertain if one type of drop is any better than another. Future trials should be of high methodological quality, have large sample sizes, and compare both oil-based and water-based solvents with placebo, no treatment or both.

Clinical practice guideline: cerumen impaction

OBJECTIVE

This guideline provides evidence-based recommendations on managing cerumen impaction, defined as an accumulation of cerumen that causes symptoms, prevents assessment of the ear, or both. We recognize that the term "impaction" suggests that the ear canal is completely obstructed with cerumen and that our definition of cerumen impaction does not require a complete obstruction. However, cerumen impaction is the preferred term since it is consistently used in clinical practice and in the published literature to describe symptomatic cerumen or cerumen that prevents assessment of the ear. This guideline is intended for all clinicians who are likely to diagnose and manage patients with cerumen impaction.

PURPOSE

The primary purpose of this guideline is to improve diagnostic accuracy for cerumen impaction, promote appropriate intervention in patients with cerumen impaction, highlight the need for evaluation and intervention in special populations, promote appropriate therapeutic options with outcomes assessment, and improve counseling and education for prevention of cerumen impaction. In creating this guideline the American Academy of Otolaryngology-Head and Neck Surgery Foundation selected a panel representing the fields of audiology, family medicine, geriatrics, internal medicine, nursing, otolaryngology-head and neck surgery, and pediatrics.

RESULTS

The panel made a strong recommendation that 1) clinicians should treat cerumen impaction that causes symptoms expressed by the patient or prevents clinical examination when warranted. The panel made recommendations that 1) clinicians should diagnose cerumen impaction when an accumulation of cerumen is associated with symptoms, or prevents needed assessment of the ear (the external auditory canal or tympanic membrane), or both; 2) clinicians should assess the patient with cerumen impaction by history and/or physical examination for factors that modify management, such as one or more of the following: nonintact tympanic membrane, ear canal stenosis, exostoses, diabetes mellitus, immunocompromised state, or anticoagulant therapy; 3) the clinician should examine patients with hearing aids for the presence of cerumen impaction during a healthcare encounter (examination more frequently than every three months, however, is not deemed necessary); 4) clinicians should treat the patient with cerumen impaction with an appropriate intervention, which may include one or more of the following: cerumenolytic agents, irrigation, or manual removal other than irrigation; and 5) clinicians should assess patients at the conclusion of in-office treatment of cerumen impaction and document the resolution of impaction. If the impaction is not resolved, the clinician should prescribe additional treatment. If full or partial symptoms persist despite resolution of impaction, alternative diagnoses should be considered. The panel offered as an option that 1) clinicians may observe patients with nonimpacted cerumen that is asymptomatic and does not prevent the clinician from adequately assessing the patient when an evaluation is needed; 2) clinicians may distinguish and promptly evaluate the need for intervention in the patient who may not be able to express symptoms but presents with cerumen obstructing the ear canal; 3) the clinician may treat the patient with cerumen impaction with cerumenolytic agents, irrigation, or manual removal other than irrigation; and 4) clinicians may educate/counsel patients with cerumen impaction/excessive cerumen regarding control measures.

DISCLAIMER

This clinical practice guideline is not intended as a sole source of guidance in managing cerumen impaction. Rather, it is designed to assist clinicians by providing an evidence-based framework for decision-making strategies. It is not intended to replace clinical judgment or establish a protocol for all individuals with this condition, and may not provide the only appropriate approach to diagnosing and managing this problem.

Safety and Efficacy of Sofenz Ceruminolytic Solution

We conducted an open-label study of 109 untreated patients who had excessive or impacted cerumen. Our goal was to evaluate the safety and efficacy of Sofenz Cerumenolytic Solution, a methyltrypsin-containing earwax removal solution. Each patient's external auditory canal was filled with Sofenz for 15 minutes. The primary measure of efficacy—visibility of the tympanic membrane—was assessed after the solution had been drained from the canal and again after the canal had been irrigated with lukewarm water. If the tympanic membrane was not completely visible following either application, the procedure was repeated. A safety examination was conducted 1 to 3 days after treatment. Secondary outcomes measures included relief of otologic symptoms (e.g., hearing loss, tinnitus, etc.) and patients’ overall satisfaction with treatment. Immediately after treatment, we found that the external auditory canal was completely visible in 81 patients (74.3%) after 1 application of Sofenz and subsequent irrigation, and in 98 patients (89.9%) after 2 applications of each. At the safety follow-up visit, we determined that the number of otologic symptoms had declined by 93.2%. A self-reported assessment completed by each patient following the procedure revealed a high degree of satisfaction with treatment. A total of 58 adverse events were reported, but only 16 were directly related to treatment, and all were transient and either mild or moderate. We conclude that 1 or 2 applications of Sofenz followed by irrigation with lukewarm water is a safe, well-tolerated, and effective treatment for excessive or impacted cerumen in the external auditory canal.

Impacted cerumen: composition, production, epidemiology and management

In the UK, some 2.3 million people suffer cerumen ('ear wax') problems serious enough to warrant management, with approximately 4 million ears syringed annually. Impacted cerumen is a major cause of primary care consultation, and a common comorbidity in ENT patients, the elderly, infirm and people with mental retardation. Despite this, the physiology, clinical significance and management implications of excessive and impacted cerumen remain poorly characterized. There are no well-designed, large, placebo-controlled, double-blind studies comparing treatments, and accordingly, the evidence surrounding the management of impacted cerumen is inconsistent, allowing few conclusions. The causes and management of impacted cerumen require further investigation. Physicians are supposed to follow the edicts and principles of evidence-based medicine and clinical governance. Currently, in patients with impacted cerumen, the lack of evidence makes this impossible.

Vitamin B12 for cognition

BACKGROUND

An association between neuropsychiatric disorders and vitamin B12 deficiency has been recognized since 1849 when pernicious anaemia was first described. It has been suggested that deficiency of vitamin B12 might contribute to age-associated cognitive impairment. Low serum vitamin B12 concentrations are found in more than 10% of older people. A high prevalence of low serum vitamin B12 levels, and other indicators of vitamin B12 deficiency have been reported among people with Alzheimer's disease. A review is needed of trials assessing effects of vitamin B12 supplementation on cognitive function in later life.

OBJECTIVES

To examine the effect of B12 supplementation on cognitive function of demented and elderly healthy people in terms of preventing the onset or progression of cognitive impairment or dementia.

SEARCH STRATEGY

The trials were identified from a search of the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group on 12 September 2002 using the terms listed in additional table 1. In addition MEDLINE 1966 to 2002/09 and EMBASE 1980-2002/08 were searched using the same terms and cognit* to pick up studies with healthy volunteers.

SELECTION CRITERIA

All randomized double-blind trials in which vitamin B12 at any dose was compared with placebo.

DATA COLLECTION AND ANALYSIS

Both reviewers applied the selection criteria to assess the quality of the studies. One reviewer collated and analysed the data. For each outcome measure data were sought on every patient randomized.

MAIN RESULTS

From the two included studies (Seal 2002; Fourniere 1997) of people with dementia and low serum vitamin B12 levels, there was no statistically significant evidence of treatment effect, vitamin B12 supplementation compared with placebo, on cognitive function.

REVIEWER'S CONCLUSIONS

Evidence of any efficacy of vitamin B12 in improving the cognitive function of people with dementia and low serum B12 levels is insufficient. The two trials of acceptable methodology (Fourniere 1997; Seal 2002) were restricted to a small number of patients with Alzheimer's disease and other types of cognitive impairment. No trials involving people without dementia or using other definitions of vitamin B12 deficiency were found.