Cobalt (Co) and its compounds are widely distributed in nature and are part of numerous anthropogenic activities. Although cobalt has a biologically necessary role as metal constituent of vitamin B, excessive exposure has been shown to induce various adverse health effects. This review provides an extended overview of the possible Co sources and related intake routes, the detection and quantification methods for Co intake and the interpretation thereof, and the reported health effects. The Co sources were allocated to four exposure settings: occupational, environmental, dietary and medical exposure. Oral intake of Co supplements and internal exposure through metal-on-metal (MoM) hip implants deliver the highest systemic Co concentrations. The systemic health effects are characterized by a complex clinical syndrome, mainly including neurological (e.g. hearing and visual impairment), cardiovascular and endocrine deficits. Recently, a biokinetic model has been proposed to characterize the dose-response relationship and effects of chronic exposure. According to the model, health effects are unlikely to occur at blood Co concentrations under 300μg/l (100μg/l respecting a safety factor of 3) in healthy individuals, hematological and endocrine dysfunctions are the primary health endpoints, and chronic exposure to acceptable doses is not expected to pose considerable health hazards. However, toxic reactions at lower doses have been described in several cases of malfunctioning MoM hip implants, which may be explained by certain underlying pathologies that increase the individual susceptibility for Co-induced systemic toxicity. This may be associated with a decrease in Co bound to serum proteins and an increase in free ionic Co. As the latter is believed to be the primary toxic form, monitoring of the free fraction of Co might be advisable for future risk assessment. Furthermore, future research should focus on longitudinal studies in the clinical setting of MoM hip implant patients to further elucidate the dose-response discrepancies.

The observed pediatric age correlations underscore the necessity of age-appropriate normative data to guarantee accurate interpretation of test results. The high percentages of abnormal vestibular test results in hearing-impaired children emphasize the importance of vestibular assessment in these children because the integrity of the vestibular system is a critical factor for motor and psychological development.

Mal de debarquement (MdD) is a subjective perception of self-motion after exposure to passive motion, in most cases sea travel, hence the name. Mal de debarquement occurs quite frequently in otherwise healthy individuals for a short period of time (several hours). However, in some people symptoms remain for a longer period of time or even persist and this is then called mal de debarquement syndrome (MdDS). The underlying pathogenesis is poorly understood and therefore, treatment options are limited. In general, limited studies have focused on the topic, but the past few years more and more interest has been attributed to MdDS and its facets, which is reflected by an increasing number of papers. Till date, some interesting reviews on the topic have been published, but a systematic review of the literature is lacking and could help to address the shortcomings and flaws of the current literature. We here present a systematic review of MdD(S) based on a systematic search of medical databases employing predefined criteria, using the terms “mal de debarquement” and “sea legs”. Based on this, we suggest a list of criteria that could aid healthcare professionals in the diagnosis of MdDS. Further research needs to address the blank gaps by addressing how prevalent MdD(S) really is, by digging deeper into the underlying pathophysiology and setting up prospective, randomized placebo-controlled studies to evaluate the effectiveness of possible treatment strategies.

Hearing-impaired children are at risk for balance deficits. A combination of rotatory chair testing and VEMP testing can predict the balance performance.