Chronic post-stroke oropharyngeal dysphagia is associated with impaired cortical activation to pharyngeal sensory inputs.

BACKGROUND AND PURPOSE: The role of afferent sensory pathways in the pathophysiology of post-stroke oropharyngeal dysphagia is not known. We hypothesized that patients with chronic post-stroke dysphagia (PSD) would show impaired sensory cortical activation in the ipsilesional hemisphere. METHODS: We studied 28 chronic unilateral post-stroke patients [17 PSD and 11 post-stroke non-dysphagic patients (PSnD)] and 11 age-matched healthy volunteers. Event-related sensory-evoked potentials to pharyngeal stimulation (pSEP) and sensory thresholds were assessed. We analyzed pSEP peak latency and amplitude (N1, P1, N2 and P2), and neurotopographic stroke characteristics from brain magnetic resonance imaging. RESULTS: Healthy volunteers presented a highly symmetric bihemispheric cortical pattern of brain activation at centroparietal areas (N1-P1 and N2-P2) to pharyngeal stimuli. In contrast, an asymmetric pattern of reduced ipsilesional activation was found in PSD (N2-P2; P = 0.026) but not in PSnD. PSD presented impaired safety of swallow (penetration-aspiration score: 4.3 ± 1.6), delayed laryngeal vestibule closure (360.0 ± 70.0 ms) and higher National Institute of Health Stroke Scale (7.0 ± 6.2 vs. 1.9 ± 1.4, P = 0.001) and Fazekas scores (3.0 ± 1.4 vs. 2.0 ± 1.1; P < 0.05) than PSnD. pSEP showed a unilateral delay at stroke site exclusively for PSD (peak-latency interhemispheric difference vs. PSnD: N1, 6.5 ± 6.7 vs. 1.1 ± 1.0 ms; N2, 32.0 ± 15.8 vs. 4.5 ± 4.9 ms; P < 0.05). CONCLUSIONS: Chronic post-stroke oropharyngeal dysphagia is associated with stroke severity and degree of leukoaraoisis. Impaired conduction and cortical integration of pharyngeal sensory inputs at stroke site are key features of chronic PSD. These findings highlight the role of sensory pathways in the pathophysiology of post-stroke oropharyngeal dysphagia and offer a potential target for future treatments.

Spatiotemporal characteristics of the pharyngeal event-related potential in healthy subjects and older patients with oropharyngeal dysfunction.

BACKGROUND: Oropharyngeal dysphagia (OD) is a highly prevalent symptom in older people. Appropriate oropharyngeal sensory feedback is essential for safe and efficient swallowing. However, pharyngeal sensitivity decreases with advancing age and could play a fundamental role in the physiopathology of swallowing dysfunction associated with aging. We aimed to characterize pharyngeal sensitivity and cortical response to a pharyngeal electrical stimulus in healthy volunteers (HV) and older patients with and without OD. METHODS: Eight young HV, eight older HV without OD, and 14 older patients with OD were studied by electroencephalography through 32 scalp electrodes. Pharyngeal event-related potentials (ERP) were assessed following electrical stimulation of the pharynx. Sensory and tolerance thresholds to the electrical stimulus and latency, amplitude, and scalp current density of each ERP component were analyzed and compared. An ERP source localization study was also performed using the sLORETA software. KEY RESULTS: Older participants (with and without OD) presented an increased sensory threshold to pharyngeal electrical stimulation (10.2 ± 1.7 mA and 11.5 ± 1.9 mA respectively), compared with young HV (6.0 ± 1.2 mA). The cortical activation of older HV in response to pharyngeal electrical stimulus was reduced compared with young HV (N2 amplitude: 0.22 ± 0.79 vs -3.10 ± 0.59, P<.05). Older patients with OD also presented disturbances to the pharyngo-cortical connection together with disrupted pattern of cortical activation. CONCLUSIONS AND INFERENCES: Older people present a decline in pharyngeal sensory function, more severe in older patients with OD. This sensory impairment might be a critical pathophysiological element and a potential target for treatment of swallowing dysfunction in older patients.

Epidemiología del Staphylococcus aureus en el Hospital Militar Córdoba / Epidemiology of the Staphylococcus aureus at the Hospital Militar Cordoba

Fueron caracterizados por medio de bacteriofagos especificos 115 cepas de Staphylococcus aureus aisladas de productos patológicos diversos provenientes de enfermos de consultorio externo, hospitalizados y portadores asintomaticos. Segun el esquema de Hennings et all. estos ultimos fueron clasificados como esporadicos, intermitentes y permanentes. En los aislamientos de pacientes de consultorio externo se observó un predominio fagovares del grupo I (35,71%), en cambio en los intrahospitalarios los fagovares de grupo III (42,86%) fueron los de mayor incidencia. No se observó correlación entre los fagovares y los patrones de sensibilidad a los antimicrobianos

Epidemiología del Staphylococcus aureus en el Hospital Militar Córdoba / Epidemiology of the Staphylococcus aureus at the Hospital Militar Cordoba

Fueron caracterizados por medio de bacteriofagos especificos 115 cepas de Staphylococcus aureus aisladas de productos patológicos diversos provenientes de enfermos de consultorio externo, hospitalizados y portadores asintomaticos. Segun el esquema de Hennings et all. estos ultimos fueron clasificados como esporadicos, intermitentes y permanentes. En los aislamientos de pacientes de consultorio externo se observó un predominio fagovares del grupo I (35,71%), en cambio en los intrahospitalarios los fagovares de grupo III (42,86%) fueron los de mayor incidencia. No se observó correlación entre los fagovares y los patrones de sensibilidad a los antimicrobianos (AU)

Fagotipia de cepas de Staphylococcus aureus aisladas en nosocomios de la ciudad de Cordoba (Argentina). / Phage typing of Staphylococcus aureus isolated in hospitals of the city of Cordoba (Argentina)

Se analizaron los resultados de la fagotipia de 477 cepas de Staphylococcus aureus por medio del conjunto basico de bacteriofagos estandarizados. Los resultados acusaron una preponderancia del grupo fagicoIII (41,50%) seguido por los bacteriofagos miscelaneos (25,99%), el grupo I (18,65%) y el grupo fagico II (6,28%). El porcentaje de cepas no tipificables por el metodo directo fue de 7,54%. El 16% de las cepas resultaron ser resistentes a la gentamicina y el 22% a la meticilina. No se constato correlacion entre un determinado fagotipo y la resistencia a la gentamicina y meticilina sugiriendose por lo tanto la independencia del factor que codifica la susceptibilidade a los antibioticos por plasmidos y la que rige la sensibilidad a los bacteriofagos. Con las cepas no tipificables por los fagos estandarizados se ensayo la fagotipia indirecta previa induccion de las cepas lisogenas con un agente fisico