Recreational Divers Research Articles

Pattern in the Co-occurrence of Fishes Inhabiting the Coral Reefs of Bonaire, Netherlands Antilles

We conducted an analysis of species associations using fish diversity and abundance surveys conducted in Bonaire Marine Park by recreational divers. We used data from the REEF (Reef Environmental Education Foundation) Fish Survey Project to compute Bray–Curtis similarity coefficients for all species pairs for the 100 most abundant species. We quantified relationships between species using hierarchical agglomerative clustering and non-metric multidimensional scaling (MDS) of the matrix of Bray–Curtis similarity coefficients. We identified three clusters of species from the analysis. MDS results showed species clusters occupied distinct regions across a continuous gradient of species in two-dimensional space, rather than form distinct clusters. While differences in habitat requirements can explain some of the pattern in pairwise species interactions, these results suggest that there are significant direct and indirect behavioral interactions mediating the distribution and abundance of species. Studies conducted to elucidate patterns of species-habitat relationships have been central to conservation planning for marine protected areas (MPAs). However, the role of behavioral interactions between species driving the dynamics of species composition within MPA networks, designed for representation of biological diversity, should be considered when selecting sites in order to be effective.

A Method for the Automated Detection of Venous Gas Bubbles in Humans Using Empirical Mode Decomposition

Doppler ultrasound signals are widely used to grade the quantity of circulating venous bubbles in divers. Current techniques rely on trained observers, making the grading process both time-consuming and subjective. The automated detection of bubbles, however, is confounded by the presence of other signals, primarily those arising from blood motion. Empirical Mode Decomposition was used here to calculate the intrinsic mode functions (IMFs) of a number of Doppler ultrasound signals from recreational divers, post-decompression. The IMFs provide a basis set for signal decomposition, each IMF corresponding to a different timescale in the signal. Each signal was found to comprise approximately 20 IMFs: the precise number being dependent upon the nature of the signal. A method is presented to detect bubbles using the IMF; features are first identified in the individual heart cycles, these having been previously determined using a robust peak detection method, by examining deviations from the ensemble averaged IMF. Bubbles are then identified as features appearing in more than one IMF, with significant energy in the original signal. This method has been applied to a subset of the available database and appears to perform with good sensitivity even when the signal has variable signal strength.

Controversies in the Medical Clearance of Recreational Scuba Divers

Primary care and sports medicine physicians are frequently consulted on medical clearance for prospective recreational divers. We discuss four common and controversial medical conditions--asthma, diabetes mellitus, coronary artery disease, and patent foramen ovale--as they relate to fitness to dive. For each condition we review the relevant anatomy and physiology, current recommendations, and the pertinent medical literature. Finally, we offer evidence-based recommendations regarding fitness to dive for potential divers with these conditions.

Population size estimate of a reef-flat aggregation of Chromodoris annulata (Opisthobranchia, Chromodoridae)

Despite numerous accounts of opisthobranch morphology, life cycle and reproduction, detailed information on field population sizes and movement distances of sea slugs remains scarce. Some recent studies have analysed growth, movement and dispersal in populations of the sea hares Aplysia vaccaria (Winkler, 1955) and A. kurodai (Baba, 1937), and the relation between environmental heterogeneity and spatial distribution in the nudibranch Onchidoris muricata (Muller, 1776), but lacked estimates of population size. Particularly little information is available for species that rarely form mating aggregations and occur at such low densities that quantitative sampling is almost impossible. As a major drawback, mark-recapturebased population size estimates in sea slugs are problematic because individual recognition is often difficult and individual tagging has thus far only been applied to large species of sea hares. Here, we present a short-term capture-recapture-study for a spatially restricted reef-flat aggregation of the tropical IndoPacific nudibranch Chromodoris annulata (Eliot, 1904). This species inhabits various sections of coral reefs, ranging from the shallow subtidal adjacent to mangrove forests up to 15 m depth near the reef crest (e.g. refs 9, 10, records by recreational divers and snorkellers at http://www.seaslugforum.net, personal observations). We surveyed a c. 3 ha (100 300 m) section of the reef-flat at Mangrove Bay (20 km south of El Quseir, Red Sea, Egypt) that covers the full gradient from the rocky and muddy intertidal next to a small mangrove mudflat to the reef crest (depth 1–3 m; Fig. 1). Following initial observations of single C. annulata, we searched the whole area on ten occasions (eight low tides, two high tides) in the eight-day period 5 to 12 May 2003. Most C. annulata were confined to a small area adjacent to the mangrove patch (Fig. 1). We therefore focused our survey effort on this 1435 m (41 m 35 m) core area. Coral rock was only sparsely covered by algae and sponges, but formed many small crevices and holes that served as hides for C. annulata. During low tide the area was partly exposed with a number of submerged small tide pools. At high tides water depths ranged between 30 and 50 cm. Highly variable patterns of purple rings around the rhinophores and orange blotches scattered over the upper mantle (Fig. 2) allowed individual recognition and were sketched for comparison with earlier observations. Sampling locations were recorded on a map in order to calculate minimum movement distances based on straight Euclidian distances between subsequent recordings. This measurement was then divided by the delay between recordings to obtain approximate minimum movement distances per day. We further estimated population size with the modified Lincoln index. This index has been developed for closed populations; i.e. it ignores immigration, emigration, births, and deaths. A closed population appears a realistic approximation for our survey period, since (i) only a single slug was found outside the study area and specimens were concentrated in the centre of the core study area, suggesting low dispersal rates, and (ii) body size distribution of C. annulata (1.5 to 8 cm; mean 4.5 cm) indicated that most animals were adult so that birth did not have a major impact on our population in the course of the study. Given the high recovery rates (see below), mortality was also assumed to be close to zero. For each survey we estimated population size as

Five-week Respiratory Muscle Training Program Effects On Lung Function And Air Consumption In Scuba Divers

PURPOSE To test the effects of a 5-wk, bi-directional respiratory muscle training (RMT) program on the lung function and underwater air consumption of recreational SCUBA divers. METHODS 12 adults (7 men, 5 women) from the local diving community volunteered and gave written consent. Inclusion criteria were age (min. 18 yr), diving certification level (min. Open Water) and freedom from medical conditions precluding participation in submaximal testing and underwater drills. Participants in this double-blind study were randomly assigned to either the treatment (T; n = 7) or control (C; n = 5) group. T received bi-directional RMT devices while C received shams; all were instructed to follow manufacturer's instructions (3 sets of 10 breaths twice daily) for 5 wk. Regular activity was to be maintained throughout the study. Pre- and post-tests included: total lung capacity (TLC), vital capacity (VC), residual volume (RV), YMCA cycle ergometry, and 30-min underwater drill for SCUBA air consumption (UAC) in a controlled environment. STATISTICS An independent t-test was used to assess the demographic and dive history similarity of the two groups. A 2 (pre vs. post) × 2 (group) repeated-measures ANOVA was run for each variable of interest to investigate training efficacy between and within the groups. SPSS-PC v10 was used for all analyses; significance was set at p ≤ .05. RESULTS The groups were similar in age (T: 25.6 ± 11.1; C: 25.0 ± 12.3 yr), ht (T: 172.4 ± 5.9; C: 179.2 ± 7.5 cm), wt (T: 80.6 ± 28.4; C: 91.2 ± 23.2 kg), diving experience (T: 3.3 ± 3.4; C: 7.1 ± 6.1 yr), and current year's diving frequency (T: 37.3 ± 34.7; C: 41.3 ± 27.8 dives); p >.05. T improved more in TLC (0.79L), VC (0.24L), RV (0.53L), estimated VO2max (1.28 ml/kg/min) and UAC (373.81 psi) than did C (0.46L, −0.17L, −0.58L, −1.43 ml/kg/min, 120.00 psi, respectfully). Main effects for TLC (F = 6.838, p = .031) and RV (F = 7.135, p = .028) were significant. No interaction effects were significant (p >.05). DISCUSSION 5 wks of RMT significantly altered TLC and RV but not VC, submaximal aerobic capacity or air consumption during a 30-min SCUBA fin kick drill in this small, diverse sample of recreational divers. Although not statistically significant the improvement in UAC following RMT may be practically significant as it may increase a diver's “bottom time”.

Five-week Respiratory Muscle Training Program Effects On Lung Function And Air Consumption In Scuba Divers

PURPOSE To test the effects of a 5-wk, bi-directional respiratory muscle training (RMT) program on the lung function and underwater air consumption of recreational SCUBA divers. METHODS 12 adults (7 men, 5 women) from the local diving community volunteered and gave written consent. Inclusion criteria were age (min. 18 yr), diving certification level (min. Open Water) and freedom from medical conditions precluding participation in submaximal testing and underwater drills. Participants in this double-blind study were randomly assigned to either the treatment (T; n = 7) or control (C; n = 5) group. T received bi-directional RMT devices while C received shams; all were instructed to follow manufacturer's instructions (3 sets of 10 breaths twice daily) for 5 wk. Regular activity was to be maintained throughout the study. Pre- and post-tests included: total lung capacity (TLC), vital capacity (VC), residual volume (RV), YMCA cycle ergometry, and 30-min underwater drill for SCUBA air consumption (UAC) in a controlled environment. STATISTICS An independent t-test was used to assess the demographic and dive history similarity of the two groups. A 2 (pre vs. post) × 2 (group) repeated-measures ANOVA was run for each variable of interest to investigate training efficacy between and within the groups. SPSS-PC v10 was used for all analyses; significance was set at p ≤ .05. RESULTS The groups were similar in age (T: 25.6 ± 11.1; C: 25.0 ± 12.3 yr), ht (T: 172.4 ± 5.9; C: 179.2 ± 7.5 cm), wt (T: 80.6 ± 28.4; C: 91.2 ± 23.2 kg), diving experience (T: 3.3 ± 3.4; C: 7.1 ± 6.1 yr), and current year's diving frequency (T: 37.3 ± 34.7; C: 41.3 ± 27.8 dives); p >.05. T improved more in TLC (0.79L), VC (0.24L), RV (0.53L), estimated VO2max (1.28 ml/kg/min) and UAC (373.81 psi) than did C (0.46L, −0.17L, −0.58L, −1.43 ml/kg/min, 120.00 psi, respectfully). Main effects for TLC (F = 6.838, p = .031) and RV (F = 7.135, p = .028) were significant. No interaction effects were significant (p >.05). DISCUSSION 5 wks of RMT significantly altered TLC and RV but not VC, submaximal aerobic capacity or air consumption during a 30-min SCUBA fin kick drill in this small, diverse sample of recreational divers. Although not statistically significant the improvement in UAC following RMT may be practically significant as it may increase a diver's “bottom time”.

Acute effects of a single open sea air dive and post-dive posture on cardiac output and pulmonary gas exchange in recreational divers

Objective: To evaluate the cardiopulmonary effects of open sea scuba air diving to 39 m (30 minutes bottom time) with standard decompression. To account for possible gravity dependent effects of...

Asthma and the Diver

Self-contained underwater breathing apparatus (scuba) diving has grown in popularity, with nearly 9 million sport divers in the United States alone. Approximately 7% of the population has been diagnosed with asthma, which is similar to the percentage of divers admitting they have asthma. Numerous concerns exist regarding subjects with asthma who choose to participate in recreational diving. Among these concerns are pulmonary barotrauma, pneumomediastinum, pneumothorax, arterial gas embolism, ear barotrauma, sinus barotrauma, and dental barotrauma. Despite these concerns, a paucity of information exists linking asthma to increased risk of diving complications. However, it has long been the norm to discourage individuals with asthma from participating in recreational scuba diving. This article examines the currently available literature to allow for a more informed decision regarding the possible risks associated with diving and asthma. It examines the underlying physiological principles associated with diving, including Henry's law and Boyle's law, to provide a more intimate understanding on physiological changes occurring in the respiratory system under compressive stress. Finally, this article offers a framework for guiding the patient with asthma who is interested in scuba diving. Under the right circumstances, the patient with asthma can safely participate in recreational diving without apparent increased risk of an asthma-related event.

Perceptions of Artificial Reefs as Scuba Diving Resources: A Study of Australian Recreational Scuba Divers

Marine-based recreation and tourism activities have experienced substantial growth over the past few decades and concerns about the ecological sustainability of many of these activities have been recognised by researchers, policy-makers and the recreation and tourism industries. One strategy to deal with diver-induced impacts is the creation of new or artificial reefs which, when established, can become substitute dive sites for more naturally occurring reefs. However, there have been very few studies into the acceptability of these substitute reef environments to divers and the social aspects of diving on artificial reefs. This paper explores the perceptions of diving on artificial reefs through a questionnaire survey of a sample of 337 Australian scuba divers. The awareness of artificial reefs as dive sites among respondents was very high, as were the levels of satisfaction with diving on such sites. Many divers recognised the value of these reefs in reducing diver impacts on natural reefs, and the study shows that artificial reefs do hold considerable attraction to divers. It is concluded that artificial reefs have significant potential for broadening the scuba diving resource base and the range of experiences available, and for simultaneously reducing visitor impacts and pressures on natural reefs.

Volunteers in Marine Conservation Monitoring: a Study of the Distribution of Seahorses Carried Out in Collaboration with Recreational Scuba Divers

Abstract: Seahorses ( Hippocampus) live in tropical and temperate waters. Habitat degradation and fishery overexploitation have led to drastic population declines on a global scale. Population monitoring is therefore essential to determine current status and manage conservation. In this first study in Italian waters on the geographic and ecological distribution of the two Mediterranean species, Hippocampus hippocampus and Hippocampus ramulosus, recreational scuba divers were recruited and trained to report sightings. A specially formulated questionnaire was produced and distributed to scuba diving schools and centers. In the 3‐year study, 2536 divers spent 6077 diving hours gathering data and completed 8827 questionnaires. Eight percent of the questionnaires showed seahorse sightings, for a total of 3061 sighted specimens, 68% of which referred to Hippocampus ramulosus. The two species had overlapping geographic distributions. Seahorse abundance varied, with the northern Adriatic Sea showing greatest abundance, followed by the central‐southern Tyrrhenian Sea. Seahorses were rare in the Ligurian and northern Tyrrhenian seas. Preferred habitats were shallow areas with either sandy bottoms or Posidonia oceanica (L.) Delile meadows. Seahorse distribution may be correlated with the degree of degradation of P. oceanica meadows. Resource users (the divers) were willing to take part in biological monitoring and contributed in scientific terms by collecting considerable amounts of data over short time periods and in economic terms by decreasing costs. The greatest limitation with volunteers was the difficulty in obtaining a uniformly distributed sample across time and space. We conclude that recreational divers and other resource users can play an active part in monitoring the marine environment and that the Mediterranean Hippocampus Mission may be used as a model for biodiversity monitoring.

Behandlung akuter kochleovestibul�rer Sch�digungen nach dem Tauchen

There has been a steady in-crease of recreational scuba divers in the last years. The majority of diving associated diseases involve otorhinolaryngology, the most important of which are cochleovestibular dysfunctions as these can lead to permanent inner ear failure. We discuss the origin and clinical symptoms, as well as the therapy, of both inner ear barotrauma and inner ear decompression illness. Our own experiences are considered together with a review of the literature from the last decade. Inner ear decompression illness seems to be a relatively common diving associated incident and is not as rare as previously thought. Hyperbaric oxygen therapy is the treatment of choice for patients with inner ear decompression sickness, but is contraindicated in patients with inner ear barotrauma. As long as an inner ear decompression illness can not be ruled out, we suggest that every patient should be treated using hyperbaric oxygen therapy but only after bilateral paracentesis.

Clinical and tympanometric findings in repeated recreational scuba diving

Due to the condition known as middle ear squeeze, scuba diving has become one of the main causes of barotrauma, and the acute form of this condition has been relatively well established. However, there are few reports available on clinical or laboratory findings in divers who practise repeated diving. The objective of the present study was to assess the otological effects of repeated dives. This was an observational study conducted on 19 recreational scuba divers, considered to be experienced divers according to the criteria established by the Professional Association of Dive Instructors (PADI). These divers undertook four dives per day on five consecutive days, and their tympanic membranes were assessed using tympanometry and otoscopy. Data were analysed using the chi(2)-test for trend. The level of statistical significance was set at p<0.05 in all analyses. The findings suggest that multiple scuba dives over a short period of time cause damage to the structures of the ear, as evidenced by the tympanometric and otoscopic findings, which revealed cumulative effects of pressure against the tympanic membrane and within the middle ear. This condition was not observed when surface intervals exceeded 11h. The results suggest that extending surface intervals may offer protection against middle ear barotrauma in recreational scuba diving.

Spinal injury considerations in the competitive diver: a case report and review of the literature

Background context Despite significant literature associated with spinal injuries and recreational diving, few articles exist regarding competitive diving injuries, with no reports pertaining specifically to spinal injuries. As a result, a case report of a collegiate diver with C5–C6 ligamentous instability requiring operative stabilization is currently presented in addition to a review of the literature. Purpose Present a case report of cervical C5–C6 ligamentous instability in a collegiate diver. Study design Case report and literature review. Methods Not applicable. Results Not applicable. Conclusions Diving injuries pertaining to competitive diving do occur but to a lesser extent than would be expected given the large forces the spine experiences. Training, experience and appropriate technique greatly minimize potential spinal hazards. Persistent complaints of neck pain after a competitive diving injury mandate aggressive evaluation and further workup.

Health aspects of diving in ENT medicine. Part I: Diving associated diseases

There has been a steady increase in the number of recreational scuba divers in the last years, with a growing number of diving associated diseases involving ENT medicine. Disorders of the ears, sinuses and pharynx are those most common in divers. In particular, external otitis and barotrauma of the middle ear are commonly treated by every ENT specialist. They usually do not lead to any permanent complaints. Incidents involving the cochleovestibular system are less common, but can result in deafness, vertigo and tinnitus, and therefore have to be treated appropriately. To treat diving medical disorders, the physician has to have some basic understanding of the physical laws that lead to diving incidents. This article will inform the reader of the forces that are encountered by divers, and then give details of the treatment of acute ENT diseases which result from diving incidents.

Retrospective evaluation of data-limited fisheries: a case from Hong Kong

This study reconstructs the likely historical changes of the data-limited Hong Kong’s inshore fisheries and evaluates their probable effects on the marine ecosystem, based on multiple information sources. Local knowledge on changes in the fisheries and the marine ecosystem is collected from commercial fishers, recreational divers and fishery officials. We combine this knowledge with results from simulation modelling and information from published and unpublished literature and reports to generate hypotheses on the historical changes in the fisheries and ecosystem between 1950 and 2000. The analyses suggest that traditionally targeted fishes had already been over-exploited by the 1970s, following a rapid drop in catch per unit effort in the 1960s. This paralleled a dramatic expansion of fishing effort. Ecosystem structure shifted as the large predatory species became depleted and small fishes and benthic invertebrates gained dominance. High demand for small fishes as fish-feed for aquaculture farms, high market price of benthic knowledge from resource users and managers provided an important, sometimes the sole, source of information to understand the fishery (Johannes, 1998; Johannes et al., 2000). In this study, we demonstrated that the use of the best available information obtained from limited landings and effort statistics, expert knowledge from resource users and managers, andAEresults from simulation modelling, provided informative qualitative and, to a certain degree, quantitative descriptions of fishery development, contributing to an understanding of fishery history and identification of management challenges. Caution is urged since the approach is based heavily on a number of assumptions that need to be carefully validated. We assumed that the interviews provided an unbiased description of the changes in fisheries and the marine ecosystem. However, psychological studies have suggested that autobiographic memory - memory that is specific, personal, and long-lasting, and usually of significance to the self-system (e.g., Thompson et al., 1996) – could be biased as a result of affective association. For instance, study on university students’ abilities to recall the grades they obtained in various subjects during high schools generally showed that memory was best for experiences that were affectively pleasant, intermediate for experiences that are unpleasant, and worst for experiences that are neutral (Koch, 1930; Waters and Leeper 1936; Thompson, 1985; Bahrick et al., 1996). Moreover, the ability to recall autobiographical memory was shown to decline with age, particularly when the events occurred in the distant past (Pascale et al., 2002). The interviewees’ memories on past marine resource abundance were generally autobiographic memory and might have affectively associated the past with the most productive years of their fishing experience. Thus the description of the past they provided might be positively biased. Information and descriptions from other independent sources help to assess the validity of the interview data and in the present study, information from different sources seemed to converge. However, future studies on autographic memory of fishers’ fishing experience could enhance the validity of the approach. The approach described in this paper is useful in retrospective analysis and diagnosis of a fishery in a data-sparse condition. However, more conventional fishery data and analytical tools may be required for fine-tuning future management and there is little substitute for regular fishery monitoring.

A 10-Year Longitudinal Study of Adherence in Recreational Scuba Divers

0450 PURPOSE: The purpose of this investigation was to examine adherence in recreational scuba divers over time. METHODS: Seventy-five certified divers (55 men and 20 women) initially completed a questionnaire pertaining to general health, selected psychological variables, and diving habits. These respondents were followedup (M = 10.6yrs; SD = 3) in an attempt to document any changes in these variables, and this report focuses on the adherence data. RESULTS: The proportion of men (65.5%) and women (65.0%) divers who considered themselves “active” divers did not differ across genders at follow-up (z = 0.04, p > .05). Men and women divers also did not differ in their estimate of METs/yr spent scuba diving at the initial assessment (461 vs. 440, t = 0.13, p > .05) or at follow-up (231 vs. 252, t = 0.17, p > .05). In light of these findings the two groups were combined for all further analyses. At follow-up, 65.3% of all respondents answered, “yes” when asked if they considered themselves to be active divers. This rate is significantly higher than one would expect in the short-term (50%, z = 1.82, p < .05), and in the long-term (25%, z = 4.92, p < .01) for other forms of exercise reported in the published literature. The number of reported METs/yr spent scuba diving decreased significantly from the initial assessment to follow-up (456 vs. 237, t = 2.70, p < .01). There was also a significant reduction for total self-reported exercise METs/yr (4305 vs. 3299, t = 2.64, p < .05). CONCLUSIONS: It is concluded that the adherence rate among recreational scuba divers is significantly higher than adherence rates previously reported for other exercisers. Supported in part by the University of Wisconsin Sea Grant Institute.

Negative neurofunctional effects of frequency, depth and environment in recreational scuba diving: the Geneva “memory dive” study

Objectives: To explore relationships between scuba diving activity, brain, and behaviour, and more specifically between global cerebral blood flow (CBF) or cognitive performance and total, annual, or last 6 months’...

Conflict and impacts of divers and anglers in a marine park.

The New South Wales State Government (Australia) gazetted the Jervis Bay Marine Park (JBMP) in 1998. During the preparation of the draft zoning plan in 2000, societal data on two conflicting park user groups--recreational scuba divers and fishers (anglers)--was collected. While conflict resolution was a plan priority, other factors, such as cumulative environmental impacts of users and protection for the critically endangered grey nurse shark (Carcharias taurus), further complicated planning. Both scuba diving and angling are primary summer activities and are disproportionately concentrated around the headlands of the bay. Furthermore, shore based game-fishing was concentrated on the northern headland, where the conflict was centered. However, when the exact locations of divers and anglers were determined, there was a partial partitioning of the available space, with only a small contested overlap. To resolve conflict and maximize positive environmental outcomes, a sanctuary zone and noanchoring zone option in the draft zoning plan was sought to formalize this partition. The human dimension data proved valuable in guiding environmental management in this politically volatile situation. A baseline study conducted 11 years previously was also used to gain a limited perspective on change in user numbers. Comparison between study periods indicated dive numbers had remained similar, while the number of dive charter trips was significantly less. The numbers of anglers, for the four months compared, had doubled and tripled. The actual data used to inform management is presented and the limitations of this "best available data" approach are discussed.

Patent foramen ovale: an underrated risk for divers?

The foramen ovale which is the fetal connection between the right and left atrium persists in about 30 % of the adult population. In the presence of a persistent foramen ovale (PFO) shunting of blood may occur from the right to the left atrium, and bubbles can reach the systemic circulation during or after the decompression phase of a dive with compressed air. Therefore, divers with PFO may have an increased risk to develop ischemic cerebral lesions and neurologic decompression sickness (DCS). Significant right-to-left shunting may be diagnosed using transcranial doppler ultrasound of the medial cerebral artery and echocardiography with echo contrast media and Valsalva provocation. However, there are no official guidelines concerning PFO screening in medical fitness exams for professional or recreational divers in Germany. Therefore, it remains in the diver's choice to be screened for PFO. Divers with a history of DCS should be monitored for PFO, especially when diving strictly adhered to decompression tables. Divers with PFO who refuse to stop diving after DCS should be advised to adhere to very save dive profiles.

Inner ear decompression sickness and inner ear barotrauma in recreational divers: a long-term follow-up.

The objectives were to report the authors' experience with the long-term follow-up of patients with diving-related inner ear decompression sickness and inner ear barotrauma and to discuss residual cochlear and vestibular damage in relation to the question of fitness to dive. Retrospective consecutive case series. Eleven recreational divers with inner ear decompression sickness and nine with inner ear barotrauma (IEB) were followed. A complete otoneurological physical examination and laboratory evaluation were carried out. The latter included audiometry, electronystagmography, a rotatory chair test using the sinusoidal harmonic acceleration protocol, and computerized dynamic posturography. Residual cochleovestibular deficits were found in 10 (91%) of the patients with inner ear decompression sickness and 3 (33%) of those with IEB (P <.02, Fisher's Exact test; odds ratio, 20). A significantly shorter follow-up period was required for the inner ear barotrauma group (P <.05, simple t test) because three patients (33%) recovered completely within 1 month of the diving accident. Eight patients had residual vestibular deficits on follow-up, but only one (12.5%) was symptomatic. However, five (56%) of the nine patients who had a cochlear insult, as documented by follow-up audiometry, complained of significant hearing loss and tinnitus. Inner ear decompression sickness carries a high risk for residual inner ear damage despite hyperbaric oxygen recompression therapy. A favorable prognosis might be anticipated for inner ear barotrauma. The finding that most patients with residual vestibular deficits were asymptomatic at the time of follow-up emphasizes the need for a complete vestibular evaluation, including specific bedside testing and laboratory examinations, before a return to diving activity may be considered.