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1.
J Alzheimers Dis ; 47(1): 185-96, 2015.
Article in English | MEDLINE | ID: mdl-26402767

ABSTRACT

BACKGROUND: Falls and fractures due to impaired balance in patients with Alzheimer's disease (AD) have an adverse effect on the clinical course of the disease. OBJECTIVE: To evaluate balance impairment in AD from the viewpoint of vestibular functional impairment. METHODS: The subjects were 12 patients with AD, 12 dementia-free elderly adults, and 12 younger adults. Vestibular function was assessed using a stepping test, caloric nystagmus, and a visual suppression (VS) test. RESULTS: The stepping test was abnormal in 9 of the 12 patients in the AD group. An abnormal stepping test was not associated with self-reported dizziness or tendency to fall. Significant VS abnormalities were present in the AD group. The suppression rate of VS was lower in AD patients with either a tendency to fall or constructional apraxia than in AD patients without either. The velocity of the rapid phase of caloric nystagmus before the VS test was similar in the AD group and the elderly control group. Significant abnormalities of both caloric nystagmus and VS were not present in either the elderly or the younger control groups. CONCLUSION: AD could involve impairments in the vestibular control of balance. The VS test is useful for assessing the tendency to fall in AD. Impairment of VS in AD might arise from cerebral vestibular cortex impairment rather than comorbid peripheral vestibular disorders.


Subject(s)
Alzheimer Disease/complications , Vestibular Diseases/etiology , Acoustic Stimulation , Age Factors , Aged , Aged, 80 and over , Alzheimer Disease/diagnostic imaging , Alzheimer Disease/drug therapy , Antipsychotic Agents/therapeutic use , Brain/diagnostic imaging , Brain/pathology , Female , Humans , Iofetamine/metabolism , Male , Nystagmus, Physiologic/physiology , Postural Balance , Psychiatric Status Rating Scales , Statistics, Nonparametric , Tomography, Emission-Computed, Single-Photon , Vestibular Diseases/diagnosis , Young Adult
2.
Neurotoxicol Teratol ; 37: 33-8, 2013.
Article in English | MEDLINE | ID: mdl-23454008

ABSTRACT

BACKGROUND: Drinking well water contaminated with the organoarsenic compound diphenylarsinic acid (DPAA) causes central nervous system (CNS) disorders that improve within several years after last drinking such water. Subjective symptoms such as lightheadedness and dizziness appear to persist, however, suggesting CNS damage. We evaluated CNS damage due to DPAA by detecting abnormal eye movements. METHODS: Subjects comprised 29 victims of exposure to DPAA in whom this substance had been detected in the nails. Investigations were performed more than 3years following cessation of DPAA exposure. Abnormal eye movements were monitored using electronystagmography. We analysed unpaired t-test between exposure subjects who exhibited upbeat nystagmus and those who did not. Upbeat nystagmus parameters were measured, and mean values were calculated. Associations between the properties of upbeat nystagmus and maximum concentrations of DPAA among DPAA exposure were also investigated. RESULTS: Upbeat nystagmus was common among exposure victims, occurring in 23 of 29 subjects (79.0%). The subjects with upbeat nystagmus had significantly higher ratio than those without upbeat nystagmus in the points of subjective symptoms and DPAA concentration of drinking water (p<0.01). The slow-phase amplitude of upbeat nystagmus enlarged with increasing DPAA concentrations, showing a significant positive correlation (p<0.05). These findings suggest that the level of exposure to DPAA affects the properties of nystagmus. High-frequency pathological square-wave jerks (SWJ) were seen in 14 of 29 patients (48.0%), and mean SWJ frequency was 112.4±16.7/min. CONCLUSIONS: Detection of abnormal ocular movements may be useful in evaluating residual/persistent/chronic CNS damage due to organoarsenic poisoning.


Subject(s)
Arsenic Poisoning/etiology , Arsenicals , Central Nervous System/drug effects , Nystagmus, Pathologic/etiology , Water Pollutants, Chemical/toxicity , Adolescent , Adult , Aged , Aged, 80 and over , Arsenic Poisoning/metabolism , Arsenic Poisoning/pathology , Arsenicals/pharmacokinetics , Case-Control Studies , Central Nervous System/pathology , Electronystagmography , Female , Humans , Japan , Male , Middle Aged , Nails/chemistry , Nystagmus, Pathologic/metabolism , Nystagmus, Pathologic/pathology , Tissue Distribution , Water Pollutants, Chemical/pharmacokinetics , Young Adult
3.
J Clin Neurosci ; 19(11): 1597-9, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22954790

ABSTRACT

Cell groups of the paramedian tract, which are located in the paramedian region of the lower brainstem, are eye-movement-related neurons that project to the cerebellar flocculus. Their inactivation produces downbeat nystagmus, which resembles eye movement disorders resulting from lesions of the cerebellar flocculus in animal experiments. Therefore, paramedian tract cells are assumed to fulfill an important function in ocular movement control, such as gaze-holding and maintaining vestibular balance. This paper presents a 50-year-old female who manifested downbeat nystagmus due to damage to the paramedian tract cells caused by a localized ischemic lesion in the medulla oblongata. We found that a paramedian medullary lesion-induced nystagmus, similar to that observed following floccular lesions, clearly indicates that a subgroup of paramedian tract cells projecting to the flocculus was impaired. This finding has important implications in considering a brainstem-cerebellar feedback loop involved in vestibulo-oculomotor controls, such as vestibular balance. Although there have been a few reports of downbeat nystagmus caused by lesions in the midline region of the lower brainstem, to our knowledge none report the occurrence of nystagmus due to a strictly localized medullar lesion, such as the one described here.


Subject(s)
Brain Stem Infarctions/complications , Brain Stem Infarctions/pathology , Medulla Oblongata/pathology , Nystagmus, Pathologic/etiology , Cerebellum/blood supply , Cerebellum/pathology , Electronystagmography , Eye Movements , Female , Fixation, Ocular/physiology , Humans , Magnetic Resonance Imaging , Middle Aged
4.
Intern Med ; 51(16): 2213-6, 2012.
Article in English | MEDLINE | ID: mdl-22892506

ABSTRACT

We report a 74-year-old woman who presented with recurrent isolated abducens nerve paresis. Cranial magnetic resonance imaging revealed that the right abducens nerve was sandwiched between the right internal carotid artery and a persistent trigeminal artery (PTA) variant, which might have led to neurovascular compression of the abducens nerve, resulting in abducens nerve damage. Normal variants of PTA, which are cerebellar arteries originating from a precavernous portion of the internal carotid artery, must be carefully observed as such variants can potentially cause a neurovascular compression of the abducens nerve.


Subject(s)
Abducens Nerve Diseases/etiology , Nerve Compression Syndromes/complications , Paresis/etiology , Trigeminal Nerve , Abducens Nerve Diseases/physiopathology , Aged , Diplopia/etiology , Electronystagmography , Eye Movements , Eye Pain/etiology , Female , Humans , Magnetic Resonance Angiography , Nerve Compression Syndromes/physiopathology , Paresis/physiopathology , Recurrence
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