SPECT (Single Photon Emission Computed Tomography) and PET (Positron Emission Tomography) are nuclear medicine imaging techniques which can examine metabolic functions of the body in three dimensions. Both methods use pharmaceutical agents labeled by radioisotopes (RIs), called tracers. In SPECT scans, RIs emit gamma radiation directly measured by gamma cameras, which rotate around the patient to acquire tomography images. Many radiopharmaceuticals are developed for different kinds of examinations; for example, 99mTc-HMPAO (hexamethyl-propyleneamine oxime) and 99mTc-ECD (ethyl cysteinate dimer) for cerebral blood flow studies, 99mTc-HMDP (hydroxylmethylene diaphosphonate) for bone scans, and 99mTc-TF (tetrofosmin) for myocardial perfusion imaging. In contrast, a positron emitted by PET tracer annihilates with an electron, producing a pair of gamma rays at almost 180 degrees to each other. These two gamma rays are detected coincidently by scintillators and photomultipliers at two different locations in a PET scanner, enabling localization of the tracers within the body. PET tracers, for example 11C, 13N, 15O, and 18F, have very short half lives and need to be produced by a cyclotron installed in the hospital. SPECT and PET tracers are biologically active and their concentrations in tissue reflect the behavior of the molecules of interest. Recent advances in this field are PET-MRI and micro PET for small animals. PET-MRI is a combination of a C-shaped MRI scanner and a PET camera, with connection between the scintillators within the MRI gantry and the photodetectors of the PET module established by multiple optical fibers. Both PET and MR images can be obtained simultaneously with better soft-tissue contrast than PET-CT images. Micro PET camera for small animals has a very high spatial resolution of about 1mm, and it is possible to study the brain activities of mice in vivo.
This study was conducted to investigate the factors of one foot balancing and beam-walking in persons with intellectual disabilities (ID). There were 181 subjects with ID (male, 126; female, 55; 14 persons with autism; 22 with Down's Syndrome (DS)). One foot balancing was measured with eyes open and with eyes closed. In the beam-walking test, the subjects were asked to walk on five types of beam 3 meters in length. A stepwise multiple regression analysis was used to analyze the results. The dependent variables were the one foot balancing score (sec) with eyes open and with eyes closed and the beam-walking score (from 0 to 5), and the independents were sex, age, height (cm), weight (kg), IQ, presence/absence of autism, and presence/absence of DS. The results were as follows: (1) The one foot balancing with eyes open only related to IQ. Persons with a higher IQ showed a higher score in all the three balance tests than those with a lower IQ. The one foot balancing with eyes closed correlated with IQ and presence/absence of autism. Autistic subjects stood longer than persons with other IDs. The beam walking correlated with IQ, presence/absence of autism, and presence/absence of DS. Autistic subjects attained a higher score than subjects with other IDs, and DS subjects had lower scores. These characteristics of balance in subjects with ID are discussed in terms of executive function, motor dysfunction, and compensatory strategies.
It is often said that the quality of life (QOL) of the patients with dizziness declines, however, there have been very few reports in which the fact has been substantiated with an actual scale. In the present study, the QOL of 552 patients, who were admitted to Yokohama City Minato Red Cross Hospital for vestibular rehabilitation, was scaled with the health survey SF-36v2. The results identified a significant decline in comparison with the national norms in all sub-scales of SF-36v2. Our study thus showed that dizziness causes a decline in the QOL for affected subjects in all sub-scales of SF-36v2. Based on our results, we anticipate that the improvement of dizziness with new treatment strategies can be scaled from the viewpoint of QOL in the future.
Normal pressure hydrocephalus (NPH) is a condition involving pathologically enlarged ventricular size with normal opening pressures on lumbar puncture. NPH is associated with a classic triad of dementia, gait disturbance, and urinary incontinence. We report on a patient with NPH presenting with repeated vertigo, headache and nausea. A 21-year-old woman complained of rotatory vertigo, pulsatile headache, nausea and tinnitus in both ears. Brain MRI findings confirmed a diagnosis of hydrocephalus. The cerebrospinal fluid opening pressure was within normal limits. Since then, the patient has continued to experience vertigo, headache and nausea several times a week, and these symptoms were resistant to medical treatments. Results of pure tone audiometry, caloric tests, and vestibular-evoked myogenic potentials were normal in both ears. One year later, she developed gait disturbance and showed vertical macro square wave jerks on a gaze-evoked nystagmus test. A lumbar tap test revealed that removal of cerebrospinal fluid temporally improved her symptoms. She underwent ventriculoparietal shunt surgery, after which she has been symptom-free. Normal results on audio-vestibular examinations and the postsurgical improvement suggested that increased pressure upon the periventricular white matter, including the central vestibular tract, might have been the cause of her symptoms.
Vertigo is one of most common complaints among emergency department patients. It is most important to check the nystagmus when emergency doctors see patients with vertigo. However, there are many cases where we cannot make any diagnosis in the otorhinolaryngological clinic the day following a patient's vertigo attack because the nystagmus has already vanished. In order to resolve this medical problem, we developed a novel method that could record nystagmus anywhere and anytime. This system is very easy for any doctor to record and save the nystagmus in the dark. As a result, we have been able to make a true diagnosis even if patients had nystagmus transiently. We expect that this recording system may lead in the future to a more fulfilling medical practice in the case of patients with vertigo.
The measurement of subjective visual vertical (SVV) is clinically used as a method to assess the degree of dysfunction in the otolith, primary vestibular nerves, and central graviceptive pathways. We measured the SVV in patients with vestibular neuritis (VN) and unilateral sudden deafness (uSD). The purpose of this study was to demonstrate the characteristics of SVV in patients with VN and uSD, and determine the relation between the SVV and other neuro-otological examinations, including vestibular evoked myogenic potentials (VEMP) and the caloric test. The SVV was measured in 25 patients suffering from VN (9 women, 16 men aged from 27 to 76 years) and 30 patients suffering from uSD (16 men and 14 women aged from 21 to 76). The SVV was tilted>2o in VN (64.0%) and in uSD (23.3%). Among the abnormal SVV patients (SVV>2o), the tilt was directed toward the affected ear in all VN patients and in 75% of uSD patients. Concerning the caloric test and VEMP in VN patients, there were no significant relationships between the percentages of abnormal SVV and the degree of canal paresis and VEMP. In uSD patients, abnormal VEMP patients tended to show an abnormal SVV. Our results suggest that the shift of the SVV was strongly affected not only by superior vestibular nerve lesions, but also by inferior vestibular lesions.
We devised a new analysis technique to display the nystagmus as an arrow based on the material for the standard examination of equilibrium. Three-dimensional eye movement image analysis was performed automatically using the public domain software ImageJ and a personal computer. The direction, amplitude and frequency of nystagmus were calculated from the result of horizontal, vertical and torsional components. The amplitude and frequency were classified into three phases based on the material for the standard examination of equilibrium. Using this technique, it was possible to display properties of the nystagmus as an arrow in detail on the computer.