Auditory hallucinations in adults with hearing impairment: a large prevalence study.

BACKGROUND: Similar to visual hallucinations in visually impaired patients, auditory hallucinations are often suggested to occur in adults with hearing impairment. However, research on this association is limited. This observational, cross-sectional study tested whether auditory hallucinations are associated with hearing impairment, by assessing their prevalence in an adult population with various degrees of objectified hearing impairment. METHODS: Hallucination presence was determined in 1007 subjects aged 18-92, who were referred for audiometric testing to the Department of ENT-Audiology, University Medical Center Utrecht, the Netherlands. The presence and severity of hearing impairment were calculated using mean air conduction thresholds from the most recent pure tone audiometry. RESULTS: Out of 829 participants with hearing impairment, 16.2% (n = 134) had experienced auditory hallucinations in the past 4 weeks; significantly more than the non-impaired group [5.8%; n = 10/173; p < 0.001, odds ratio 3.2 (95% confidence interval 1.6-6.2)]. Prevalence of auditory hallucinations significantly increased with categorized severity of impairment, with rates up to 24% in the most profoundly impaired group (p < 0.001). The corrected odds of hallucination presence increased 1.02 times for each dB of impairment in the best ear. Auditory hallucinations mostly consisted of voices (51%), music (36%), and doorbells or telephones (24%). CONCLUSIONS: Our findings reveal that auditory hallucinations are common among patients with hearing impairment, and increase with impairment severity. Although more research on potential confounding factors is necessary, clinicians should be aware of this phenomenon, by inquiring after hallucinations in hearing-impaired patients and, conversely, assessing hearing impairment in patients with auditory hallucinations, since it may be a treatable factor.

Auditory hallucinations, top-down processing and language perception: a general population study.

BACKGROUND: Studies investigating the underlying mechanisms of hallucinations in patients with schizophrenia suggest that an imbalance in top-down expectations v. bottom-up processing underlies these errors in perception. This study evaluates this hypothesis by testing if individuals drawn from the general population who have had auditory hallucinations (AH) have more misperceptions in auditory language perception than those who have never hallucinated. METHODS: We used an online survey to determine the presence of hallucinations. Participants filled out the Questionnaire for Psychotic Experiences and participated in an auditory verbal recognition task to assess both correct perceptions (hits) and misperceptions (false alarms). A hearing test was performed to screen for hearing problems. RESULTS: A total of 5115 individuals from the general Dutch population participated in this study. Participants who reported AH in the week preceding the test had a higher false alarm rate in their auditory perception compared with those without such (recent) experiences. The more recent the AH were experienced, the more mistakes participants made. While the presence of verbal AH (AVH) was predictive for false alarm rate in auditory language perception, the presence of non-verbal or visual hallucinations were not. CONCLUSIONS: The presence of AVH predicted false alarm rate in auditory language perception, whereas the presence of non-verbal auditory or visual hallucinations was not, suggesting that enhanced top-down processing does not transfer across modalities. More false alarms were observed in participants who reported more recent AVHs. This is in line with models of enhanced influence of top-down expectations in persons who hallucinate.

Hallucinations in patients with borderline personality disorder: characteristics, severity, and relationship with schizotypy and loneliness.

OBJECTIVE: In patients with borderline personality disorder (BPD), data are lacking on characteristics and severity of hallucinations in modalities other than the auditory (verbal) type. The same applies to relationships between hallucinations and the severity of depression, anxiety, schizotypy, and loneliness. METHODS: In 60 female patients with BPD (37 also with hallucinations), this cross-sectional study explored characteristics and severity of (i) hallucinations and (ii) schizotypal features, (iii) severity of depression and anxiety, and (iv) loneliness, and the relationships between hallucinations and the other characteristics. RESULTS: In patients with hallucinations, 80% experienced hallucinations in more than one modality; in the different modalities, the characteristics of the hallucinations were similar. The criteria for loneliness were fulfilled in 81% and 48% of patients with and without hallucinations. Compared to patients with BPD without hallucinations, the presence of hallucinations was associated with higher scores for depression, anxiety, loneliness, and schizotypy. Furthermore, the severity of hallucinations showed a positive correlation with the severity of loneliness and schizotypy. CONCLUSION: Patients with BPD experienced hallucinations with characteristics similar to the more frequently studied auditory (verbal) hallucinations. Higher scores for schizotypy and loneliness indicate that patients with hallucinations had more characteristics of cluster A personality disorders.