ABSTRACT
Transcranial ultrasound (TCS) has been shown to reveal hyperechogenicity of the substantia nigra (SN) in Parkinsonian patients and in about 10% of healthy controls. It is hypothesized that SN hyperechogenicity in healthy subjects is a vulnerability marker for idiopathic Parkinson's disease (IPD). Although there is strong evidence that the echomarker results from increased local iron content, the exact pathophysiological mechanisms remain incompletely understood. Thus, prognostic impact can only be estimated. We examined 14 subjects with SN hyperechogenicity (SN+) (7 IPD patients and 7 controls) and 7 healthy controls without the echomarker (SN-) by a magnetic resonance imaging method (MRI; T2 relaxation times) known to reveal tissue inhomogeneity following abnormal iron content and by F-Dopa PET to assess nigrostriatal function.
Subject(s)
Dihydroxyphenylalanine/analogs & derivatives , Echoencephalography/methods , Magnetic Resonance Imaging/methods , Neurons/diagnostic imaging , Neurons/pathology , Parkinson Disease/diagnosis , Positron-Emission Tomography/methods , Adult , Female , Humans , Male , Middle Aged , Radiopharmaceuticals , Reference Values , Substantia Nigra/diagnostic imaging , Substantia Nigra/pathologyABSTRACT
OBJECTIVES: Previous studies suggest that the nigrostriatal dopaminergic transmission is impaired in patients with primary orthostatic tremor. METHODS: We used transcranial sonography (TCS) to examine the morphology of the substantia nigra (SN) in four patients with primary orthostatic tremor (OT). RESULTS: TCS revealed an SN echogenicity in all patients, in three patients unilaterally, in one patient bilaterally. CONCLUSIONS: Our data suggest nigrostriatal dopaminergic deficits in OT patients. The exact impact of these dopaminergic deficits on OT generation is unclear.
Subject(s)
Substantia Nigra/pathology , Tremor/pathology , Aged , Humans , Male , Middle Aged , Motor Activity/physiology , Ultrasonography, Doppler, TranscranialABSTRACT
We report on a 70-year-old female patient with Parkinson's disease, who showed an improvement of a preexisting apraxia of lid opening on electrical impulses, so-called deep brain stimulation (DBS) delivered to the subthalamic nucleus (STN). This was not described by any other authors before. Up to now, the appearance of apraxia of lid opening was observed only as a side effect after deep brain stimulation in the nucleus subthalamicus. We suggest that these differences may be due to the region of the nucleus subthalamicus that is influenced by the stimulation.
Subject(s)
Apraxias/therapy , Electric Stimulation Therapy , Eyelid Diseases/therapy , Parkinson Disease/complications , Subthalamic Nucleus/physiopathology , Aged , Apraxias/etiology , Eyelid Diseases/etiology , Female , Humans , Recovery of FunctionABSTRACT
OBJECTIVE: Primary orthostatic tremor (OT) is thought to be generated by a unique supraspinal tremor generator. Here we studied the effect of ipsi- and contralateral stimulation of the central and peripheral nervous system on OT. METHODS: In 7 patients with primary OT, surface EMG was recorded from both tibialis anterior muscles. We performed transcranial magnetic stimulation (TMS) over the vertex, and lumbar magnetic stimulation (LMS) over the lumbar spine. Supramaximal electrical nerve stimuli were applied to the tibial or peroneal nerve at the knee. Proprioceptive input was evoked by rhythmical submaximal stimulation of the tibial, peroneal or sural nerve at the ankle. RESULTS: TMS reset OT significantly in the contralateral as well as the ipsilateral tibialis anterior muscle. The resetting in both muscles was identical. In contrast, peripheral input by means of LMS, supra- or submaximal nerve stimulation had no impact on OT. CONCLUSIONS: Transcranial magnetic stimulation of one cortical leg area resets OT in both legs whereas OT is not modified by any peripheral stimuli applied in this study. SIGNIFICANCE: Our results support the hypothesis of n unique supraspinal OT generator. This generator receives a modulating input from the motor cortex.
Subject(s)
Leg/physiopathology , Motor Cortex/physiopathology , Muscle, Skeletal/physiopathology , Posture , Spinal Cord/physiopathology , Tremor/physiopathology , Aged , Ankle , Electric Stimulation/methods , Electromyography , Female , Humans , Knee , Lumbosacral Region , Magnetics , Male , Middle Aged , Peroneal Nerve/physiopathology , Proprioception , Sural Nerve/physiopathology , Syndrome , Tibial Nerve/physiopathologyABSTRACT
Neuropathological studies show frequent and extensive effects on the visual system in Creutzfeldt-Jakob disease (CJD), but deterioration of vision is not reported by all patients. We examined the function of the visual system by means of visual evoked potentials (VEP). We recorded monocular pattern-reversal VEP in six patients with sporadic CJD 1-13 months after first symptoms occurred. Three patients had normal vision, and in a further three, vision was impaired. All patients had pathological VEP with a delayed P100 component (six eyes) or loss of cortical response (five eyes). The patients with visual impairment vs those without were not different concerning VEP findings. The VEP are already pathological in initial CJD stages and point to an early effect on the visual system in CJD, irrespective of clinical visual deficits.
