RESUMEN
OBJECTIVE: To explore the neurochemical basis of REM sleep behavior disorder (RBD) in multiple-system atrophy (MSA). METHODS: In 13 patients with probable MSA, nocturnal, laboratory-based polysomnography was used to rate the severity of REM atonia loss by the percentage of REM sleep with tonically increased electromyographic (EMG) activity and the percentage of REM sleep with phasic EMG bursts. PET with (+)-[11C]dihydrotetrabenazine ([11C]DTBZ) was employed to measure the density of striatal monoaminergic terminals and SPECT with (-)-5-[123I]iodobenzovesamicol ([123I]IBVM) to measure the density of 123I]IBVM. RESULTS: Age and gender distributions were similar in patient and normal control groups. The MSA subjects showed decreased mean [11C]DTBZ binding in the striatum (p < 0.0001) and decreased [123I]IBVM binding in the thalamus (p < 0.001). Moreover, in the MSA group, striatal [11C]DTBZ binding was inversely correlated with the severity of REM atonia loss (p = 0.003). Thalamic [123I]IBVM binding, however, was not correlated to the severity of REM atonia loss. CONCLUSION: Decreased nigrostriatal dopaminergic projections may contribute to RBD in MSA.
Asunto(s)
Monoaminas Biogénicas/metabolismo , Cuerpo Estriado/metabolismo , Atrofia de Múltiples Sistemas/fisiopatología , Trastorno de la Conducta del Sueño REM/diagnóstico , Trastorno de la Conducta del Sueño REM/metabolismo , Tetrabenazina/análogos & derivados , Adulto , Distribución por Edad , Anciano , Unión Competitiva , Radioisótopos de Carbono , Cuerpo Estriado/diagnóstico por imagen , Electromiografía , Femenino , Humanos , Radioisótopos de Yodo , Masculino , Persona de Mediana Edad , Atrofia de Múltiples Sistemas/complicaciones , Atrofia de Múltiples Sistemas/metabolismo , Piperidinas , Polisomnografía , Valor Predictivo de las Pruebas , Trastorno de la Conducta del Sueño REM/etiología , Valores de Referencia , Distribución por Sexo , Tetrahidronaftalenos , Tálamo/diagnóstico por imagen , Tálamo/metabolismo , Tomografía Computarizada de Emisión , Tomografía Computarizada de Emisión de Fotón ÚnicoRESUMEN
OBJECTIVE: To explore the neurochemical basis of obstructive sleep apnea (OSA) in multiple-system atrophy (MSA). METHODS: In 13 patients with probable MSA, nocturnal, laboratory-based polysomnography was used to rate the severity of OSA using the apnea-hypopnea index during sleep. SPECT with (-)-5-[123I]iodobenzovesamicol ([123I]IBVM) was utilized to measure the density of thalamic cholinergic terminals, which project from the brainstem pedunculopontine and laterodorsal tegmental nuclei. PET with (+)-[11C]dihydrotetrabenazine ([11C]DTBZ) was also used to measure the density of striatal monoaminergic terminals, which project from the brainstem. Findings in the patient group were compared with data from 12 normal control subjects scanned utilizing [123I]IBVM and 15 normal control subjects utilizing [11C]DTBZ. RESULTS: Age and gender distributions were similar in patient and control groups. The MSA subjects showed decreased [123I]IBVM binding in the thalamus (p < 0.001) and decreased mean [11C]DTBZ binding in the striatum (p < 0.0001) in comparison with the control subjects. In the MSA group, thalamic [123I]IBVM binding was inversely correlated with the severity of OSA (p = 0.011). Striatal [11C]DTBZ binding was not correlated with the severity of OSA (p = 0.19). CONCLUSION: Decreased pontine cholinergic projections may contribute to OSA in MSA.
Asunto(s)
Cuerpo Estriado/metabolismo , Proteínas de Transporte de Membrana , Atrofia de Múltiples Sistemas/fisiopatología , Neuropéptidos , Receptores Colinérgicos/deficiencia , Apnea Obstructiva del Sueño/diagnóstico , Apnea Obstructiva del Sueño/metabolismo , Tetrabenazina/análogos & derivados , Tálamo/metabolismo , Proteínas de Transporte Vesicular , Adulto , Distribución por Edad , Anciano , Unión Competitiva , Proteínas Portadoras/metabolismo , Cuerpo Estriado/diagnóstico por imagen , Femenino , Humanos , Radioisótopos de Yodo , Masculino , Glicoproteínas de Membrana/metabolismo , Persona de Mediana Edad , Atrofia de Múltiples Sistemas/complicaciones , Atrofia de Múltiples Sistemas/diagnóstico por imagen , Proyectos Piloto , Piperidinas , Puente/fisiopatología , Receptores Colinérgicos/metabolismo , Valores de Referencia , Análisis de Regresión , Distribución por Sexo , Apnea Obstructiva del Sueño/etiología , Tetrahidronaftalenos , Tálamo/diagnóstico por imagen , Tomografía Computarizada de Emisión , Tomografía Computarizada de Emisión de Fotón Único , Proteínas de Transporte Vesicular de Acetilcolina , Proteínas de Transporte Vesicular de Aminas BiógenasRESUMEN
Diaphragm pacing (DP) by electrical stimulation of the phrenic nerve offers important advantages to a highly select group of patients with respiratory paralysis. The patient wears an external radiofrequency (RF) transmitter over an implanted receiver, and a stimulating current is induced without the need for any transcutaneous wires. We review the conditions and requirements of patients who may benefit most from DP. We outline the preoperative evaluation and procedures for surgical implantation. We discuss the risk of diaphragmatic fatigue posed by initiation of DP and the use of gradual conditioning to limit this problem. Other problems encountered by patients in the course of DP can be minimized by well-instructed home caregivers and by systematic medical follow-up. Although a few patients derive considerable benefit from DP, many patients with respiratory paralysis are better treated by less invasive means such as nasal bilevel positive airway pressure or intermittent positive pressure ventilation, which we also review.