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Introducción: El mareo perceptual postural persistente (MPPP) es, probablemente, la causa más prevalente de mareo crónico. Sin embargo, su fisiopatología es aún motivo de duda y debate. En el presente artículo, proponemos que el MPPP se caracteriza por disfunciones cognitivas de orden superior, al punto de diferenciarse en estas dimensiones de controles sanos y pacientes con patologías vestibulares no-MPPP. Objetivo: Determinar si pacientes con MPPP presentan alteraciones discriminantes respecto a grupos controles, en ámbitos de atención, memoria de trabajo visoespacial, planificación espacial, funciones ejecutivas y rendimiento cognitivo global. Material y Método: Estudio descriptivo transversal con sujetos de entre 18 y 65 años, reclutados de una unidad de otoneurología ambulatoria. Se aplicaron pruebas Montreal Cognitive Assessment (MoCA), tarea de retención de dígitos, Trail Making Test, Corsi Block-Tapping Task y Torre de Londres. Resultados: 30 pacientes fueron categorizados en tres grupos: grupo MPPP (n = 14), grupo vestibular no-MPPP (n = 11) y grupo control (n = 5). El grupo MPPP exhibió un rendimiento significativamente inferior en pruebas de planificación, velocidad de procesamiento y funciones ejecutivas en ámbitos visoespaciales, mientras que en atención y memoria visoespacial no hubo diferencias entre grupos. Conclusión: El MPPP podría caracterizarse por una disfunción de procesos cognitivos superiores de construcción espacial de mayor complejidad, respetando funciones visoespaciales de menor orden como la memoria de trabajo. Estos hallazgos ofrecen nuevas luces para comprender la fisiopatología del MPPP y sus implicancias clínicas.
Introduction: Persistent postural-perceptual dizziness (PPPD) is probably the most prevalent cause of chronic dizziness. However, its pathophysiology is still a matter of uncertainty and debate. In this article, we propose that PPPD is characterized by higher-order cognitive dysfunctions, to the point of differentiating it from healthy controls and patients with non-PPPD vestibular pathologies. Aim: To determine whether patients with PPPD exhibit discriminant alterations compared to control groups in the areas of attention, visuospatial working memory, spatial planning, executive functions, and global cognitive performance. Materials and Methods: A cross-sectional descriptive study was conducted with subjects between the ages of 18 and 65 years, recruited from an outpatient otoneurology unit. Tests included the Montreal Cognitive Assessment (MoCA), digit retention task, Trail Making Test, Corsi Block-Tapping Task, and the Tower of London. Results: 30 patients were categorized into three groups: PPPD group (n = 14), non-PPPD vestibular group (n = 11), and control group (n = 5). The PPPD group showed significantly lower performance on tests of planning, processing speed, and executive function in visuospatial domains, while there were no differences between groups in attention and visuospatial memory. Conclusion: PPPD may be characterized by dysfunction of higher-order cognitive processes related to spatial construction of greater complexity, while sparing lower-order visuospatial functions such as working memory. These findings offer new insights into the pathophysiology of PPPD and its clinical implications.
Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Pessoa de Meia-Idade , Idoso , Adulto Jovem , Postura/fisiologia , Tontura/fisiopatologia , Percepção de Movimento/fisiologia , Doença Crônica , Epidemiologia Descritiva , Disfunção Cognitiva/fisiopatologia , Navegação Espacial/fisiologia , Memória de Curto Prazo/fisiologiaRESUMO
(1) Background: Persistent postural-perceptual dizziness (PPPD) is a common chronic dizziness disorder with an unclear pathophysiology. It is hypothesized that PPPD may involve disrupted spatial cognition processes as a core feature. (2) Methods: A cohort of 19 PPPD patients underwent psycho-cognitive testing, including assessments for anxiety, depression, memory, attention, planning, and executive functions, with an emphasis on spatial navigation via a virtual Morris water maze. These patients were compared with 12 healthy controls and 20 individuals with other vestibular disorders but without PPPD. Vestibular function was evaluated using video head impulse testing and vestibular evoked myogenic potentials, while brain magnetic resonance imaging was used to exclude confounding pathology. (3) Results: PPPD patients demonstrated unique impairments in allocentric spatial navigation (as evidenced by the virtual Morris water maze) and in other high-demand visuospatial cognitive tasks that involve executive functions and planning, such as the Towers of London and Trail Making B tests. A factor analysis highlighted spatial navigation and advanced visuospatial functions as being central to PPPD, with a strong correlation to symptom severity. (4) Conclusions: PPPD may broadly impair higher cognitive functions, especially in spatial cognition. We discuss a disruption in the creation of enriched cognitive spatial maps as a possible pathophysiology for PPPD.
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Abstract Introduction Persistent postural-perceptual dizziness (PPPD) is a functional vestibular disorder characterized by chronic dizziness, unsteadiness, and hypersensitivity to motion. Preexisting anxiety disorders and neurotic personality traits confer vulnerability to PPPD. High anxiety during acute vertigo or dizziness incites it. A functional magnetic resonance imaging (fMRI) study of chronic subjective dizziness found unexpectedly hypoactive responses to vestibular stimulation in cortical regions that integrate threat assessment and spatial perception. Objective This fMRI study used non-moving, but emotionally charged visual stimuli to investigate the brain's activity of PPPD patients and control subjects. Methods The participants included 16 women with PPPD and 16 age-matched women who recovered completely from acute episodes of vertigo or dizziness capable of triggering PPPD. Brain responses to positive, neutral, and negative figures from the International Affective Picture System were measured with fMRI and compared between the groups. Dizziness handicap, anxiety, and depression were assessed with validated questionnaires. Results Between group analyses: Participants with PPPD showed reduced activity in anterior cingulate cortex and increased activity in left angular gyrus in response to negative versus positive stimuli, which was not observed in recovered individuals. Within group analyses: Participants with PPPD had increased activity in visuospatial areas (parahippocampal gyrus, intraparietal sulcus) in negative versus positive and negative versus neutral contrasts, whereas recovered individuals had increased activity in anxiety regions (amygdala, orbitofrontal cortex). Conclusion Patients with PPPD may be more attuned to spatial elements than to the content of emotionally charged visual stimuli.
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Introduction Persistent postural-perceptual dizziness (PPPD) is a functional vestibular disorder characterized by chronic dizziness, unsteadiness, and hypersensitivity to motion. Preexisting anxiety disorders and neurotic personality traits confer vulnerability to PPPD. High anxiety during acute vertigo or dizziness incites it. A functional magnetic resonance imaging (fMRI) study of chronic subjective dizziness found unexpectedly hypoactive responses to vestibular stimulation in cortical regions that integrate threat assessment and spatial perception. Objective This fMRI study used non-moving, but emotionally charged visual stimuli to investigate the brain's activity of PPPD patients and control subjects. Methods The participants included 16 women with PPPD and 16 age-matched women who recovered completely from acute episodes of vertigo or dizziness capable of triggering PPPD. Brain responses to positive, neutral, and negative figures from the International Affective Picture System were measured with fMRI and compared between the groups. Dizziness handicap, anxiety, and depression were assessed with validated questionnaires. Results Between group analyses: Participants with PPPD showed reduced activity in anterior cingulate cortex and increased activity in left angular gyrus in response to negative versus positive stimuli, which was not observed in recovered individuals. Within group analyses: Participants with PPPD had increased activity in visuospatial areas (parahippocampal gyrus, intraparietal sulcus) in negative versus positive and negative versus neutral contrasts, whereas recovered individuals had increased activity in anxiety regions (amygdala, orbitofrontal cortex). Conclusion Patients with PPPD may be more attuned to spatial elements than to the content of emotionally charged visual stimuli.
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Objective: To determine whether performance in a virtual spatial navigational task is poorer in persistent postural perceptual dizziness (PPPD) patients than in healthy volunteers and patients suffering other vestibular disorders. Methods: Subjects were asked to perform three virtual Morris water maze spatial navigational tasks: (i) with a visible target, (ii) then with an invisible target and a fixed starting position, and finally (iii) with an invisible target and random initial position. Data were analyzed using the cumulative search error (CSE) index. Results: While all subjects performed equally well with a visible target, the patients with PPPD (n = 19) performed poorer (p < 0.004) in the invisible target/navigationally demanding tasks (CSE median of 8) than did the healthy controls (n = 18; CSE: 3) and vestibular controls (n = 19; CSE: 4). Navigational performance in the most challenging setting allowed us to discriminate PPPD patients from controls with an area under the receiver operating characteristic curve of 0.83 (sensitivity 78.1%; specificity 83.3%). PPPD patients manifested more chaotic and disorganized search strategies, with more dispersion in the navigational pool than those of the non-PPPD groups (standard distance deviation of 0.97 vs. 0.46 in vestibular controls and 0.20 in healthy controls; p < 0.001). Conclusions: While all patients suffering a vestibular disorder had poorer navigational abilities than healthy controls did, patients with PPPD showed the worst performance, to the point that this variable allowed the discrimination of PPPD from non-PPPD patients. This distinct impairment in spatial navigation abilities offers new insights into PPPD pathophysiology and may also represent a new biomarker for diagnosing this entity.
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BACKGROUND/OBJECTIVE: Persistent postural-perceptual dizziness (PPPD) was defined by expert consensus for the forthcoming International Classification of Diseases, 11th edition. Its diagnostic criteria were derived from phobic postural vertigo and chronic subjective dizziness. Two key symptoms are postural unsteadiness and visually induced dizziness. We observed that patients with PPPD tended to perform poorly on multiple conditions of the EquiTest® Sensory Organization Test (SOT) and sought to investigate this phenomenon systematically. METHODS: We examined cross-sectional, pair-wise group differences in mean scores from SOT conditions 1-6 and composite scores among 20 patients with PPPD, 15 patients recovered from acute vestibular syndromes, and 15 normal individuals (all female, 43 ± 9 years old). We also compared proportions of patients in each group with abnormal sensory analyses, and poor performance across multiple conditions. RESULTS: Patients with PPPD had significantly lower mean scores than normal individuals on conditions 2-6 and the composite, and lower than recovered patients on conditions 2-3. Recovered patients had significantly lower mean scores than normal individuals on conditions 4-6 and the composite. Patients with PPPD had the greatest likelihood of abnormal sensory analyses. CONCLUSIONS: Patients with PPPD had difficulties with postural control across multiple sensory challenges, consistent with postulated neurophysiologic mechanisms of this condition.