Impaired navigation skills in patients with psychological distress and chronic peripheral vestibular hypofunction without vertigo.

Few studies have focused on the role of the vestibular system for navigation and spatial memory functions in humans, with controversial results. Since most experimental settings were based on magnetic resonance imaging volumetry of the hippocampus and virtual navigation task on a PC, aim of this study was to investigate whether a well-compensated unilateral peripheral vestibular hypofunction in humans could interfere with navigation tasks while walking on memorized routes. A series of 50 unilateral labyrinthine-defective patients, without vertigo at the time of examination, and 50 controls were invited to visually memorize 3 different routes (a triangle, a circle and a square) on a grey carpet and then to walk along them clockwise and counter-clockwise (mental map navigation) with eyes closed. The same test was then repeated with eyes open (actual navigation) and a second time with eyes closed (mental navigation). Execution time was recorded in each test. In the same session, working spatial memory was assessed by the Corsi block test and all subjects completed the Symptom Check List (SCL-90) to assess depression and anxiety levels. Results showed that labyrinthine-defective patients presented higher levels of anxiety and depression and performed the Corsi block test with more difficulties than controls. All differences reached statistically significant level (p < 0.05). Moreover, patients needed more time than controls in the first and third navigation tasks (eyes closed). No difference was observed between clockwise and counter-clockwise walking, on all routes, either in patients or controls. Patients showed a greater improvement in the third navigation task, with respect to the first test, than controls, with no side-effect in relation to labyrinthine hypofunction. These data demonstrate that walking along memorized routes without vision is impaired by peripheral vestibular damage even if vestibular compensation prevents patients from suffering from vertigo and balance disturbances. This impairment could be due to a permanent deficit of visuo-spatial short-term memory as suggested by the Corsi block test results even if a residual sensori-motor impairment and/or an interference of psychological distress could not be excluded.

Measuring the psychosocial consequences of hearing loss in a working adult population: focus on validity and reliability of the Italian translation of the hearing handicap inventory.

Despite increasing demand for questionnaires for assessing hearing handicap and the effectiveness of some tools across different languages, empirical studies to evaluate the reliability and the validity of translations of original English questionnaires into an Italian version have not been reported in the literature, thus making comparisons of Italian experimental and clinical data across cultures and countries impossible. This study tested the global assumption that the Hearing Handicap Inventory for Adults (HHIA), that is one of the most widely used instruments in English-speaking countries, can be adapted to the Italian language maintaining the reliability and clinical validity of the original version. The English version of this 25-item, self-assessment questionnaire was developed by Newman et al. in 1990 and special emphasis was placed on emotional reaction and social limitations perceived by hearing-impaired subjects and scored separately. This tool was translated into the Italian language by a forward and backward technique, as established by the IQOLA (International Quality of Life Assessment) project. Overall, 94 subjects, aged 18-65 years, with acquired hearing impairment and 104 individuals with no hearing problems, well-matched for socio-demographic variables, were enrolled in the study in a case-control design. Reliability of the Italian version of HHIA was tested by measuring internal consistency and test-retest reproducibility. Validity was assessed by using construct, convergent and discriminant methods. A Cronbach's alpha coefficient near 0.90 confirmed a more than acceptable internal consistency and a highly statistically significant Spearman's correlation coefficient (< 0.005) between scores of the two administrations at an interval of one month documented an excellent stability of the questionnaire over time. Construct validity was demonstrated by a correlation between the severity of hearing loss and the score of questionnaire (< 0.005) and convergent validity was supported by a significant correlation between the scores of the emotional and socio/situational subscales of the HHIA to the analogous subscales of a health-related quality of life questionnaire (MOS 36-Item Short Form Health Survey) (< 0.005). Finally, since hearing-impaired subjects scored significantly higher than controls on HHIA (< 0.005), it clearly emerged that also the Italian version of HHIA differentiates the two populations (those with and those without hearing problems) demonstrating a robust discriminant validity. Given the lack of appropriate measures to assess hearing handicap in Italy, the results achieved in this study, confirm that the HHIA, Italian version, is suitable for both experimental and clinical use.

[Peripheral vestibular damage causes impaired navigation tasks on memorized routes in humans].

OBJECTIVES: To investigate if a well-compensated unilateral peripheral vestibular hypofunction could interfere with navigation tasks on memorized routes in humans. METHODS: After a complete otoneurological investigation, fifty labyrinthine-defective patients and fifty controls were invited to visually memorize three different routes (a triangle, a circle and a square) on a grey carpet and then to walk along them with eye closed clockwise and counter-clockwise (mental map navigation). The same test was then repeated with eye open (actual navigation) and again with eye closed (mental navigation). Execution time was recorded in each test. Corsi block test and a psychiatric questionnaire completed the neuropsychological examination. RESULTS: Labyrinthine-defective patients showed higher levels of anxiety and depression and performed Corsi block test with more difficulties than controls. Patients spent more time than controls in the first and third session (eye closed). No difference was recorded between clockwise and counter-clockwise navigation tasks both in patients and in controls. Patients showed a greater improvement in the third navigation task than controls. CONCLUSION: Walking on memorized routes in non-visual condition is impaired by a peripheral vestibular damage, even if patients are well compensated. This impairment could be due to a defect of the visuospatial short-term memory, as supported by Corsi block tests, but a residual sensorimotor impairment and/or an interference of psychological distress could not be definitively excluded.

Clinical examination of labyrinthine-defective patients out of the vertigo attack: sensitivity and specificity of three low-cost methods.

Many reports have appeared in the medical literature concerning the clinical examination at the bedside of patients with vertigo and, even if few controversial opinions exist, the observation of one or more kinds of nystagmus is generally regarded as suggesting an organic aetiology. So far, the presence of nystagmus has been generally considered to be crucially important for clinicians who are daily asked to differentiate between an "organic" cause of vertigo (for example, a labyrinthine dysfunction) and a "non-organic" cause of vertigo, such as a panic disorder. Albeit, it should not be forgotten that the central nervous system is able to resolve the asymmetry of vestibulo-ocular reflexes, due to a peripheral vestibular failure, by means of compensatory mechanisms so that nystagmus is rapidly abolished after the acute attack of vertigo. In addition, visual fixation elicits sub-cortical inhibitory pathways to the vestibular nuclei so that spontaneous nystagmus is remarkably reduced by light. In order to more easily detect nystagmus, attempts have been made to minimize the interference of visual fixation by means of positive lenses (Frenzel's glasses) and light occluding masks with infrared cameras (videonystagmoscopy) which have in part replaced direct observation of the patient's eyes, albeit no systematic validation of the advantages has been reported yet. To investigate the usefulness of these 3 low-cost methods to detect nystagmus, 528 outpatients presenting peripheral vestibular hypofunction, diagnosed by a complete audiological and vestibular examination, including caloric tests, were enrolled in the present study, while 133 subjects with normal vestibular function acted as a control group. All patients and control subjects underwent a standardized clinical examination based on search for spontaneous, positioning and head-shaking nystagmus detected by direct observation of patient's eyes, Frenzel's glasses and videonystagmoscopy. Specificity of the three techniques were 35.6, 43.7 and 91.6, whilst sensitivity was 88.7, 88.7 and 84.2, respectively. Finally, discriminant analysis based on the presence/absence of at least one kind of nystagmus was computed for each technique and showed that videonystagmoscopy allowed the examiner to correctly classify both pathological and normal subjects more frequently (> 77% of cases) than the other two methods (about 50%). It is concluded that only videonystagmoscopy is an acceptable technique for screening a labyrinth defect in a population of outpatients with vertigo.