Examination of the Patient with Dizziness or Imbalance.

Dizziness and imbalance are common and challenging chief complaints carrying high morbidity, due to their association with falls, injuries, and loss of quality of life. The physical examination represents an opportunity to collect objective clinical data that facilitate an understanding of symptoms that might otherwise be enigmatic and ineffable. This review focuses on the examination techniques used routinely by physicians who provide specialized care for patients with dizziness and imbalance.

Dizziness.

Dizziness is a common symptom encountered by all physicians. Dizziness and related symptoms are frequently linked to 1 or more of a list of contributors that includes benign paroxysmal positional vertigo, Ménière disease, migraine, acute peripheral vestibulopathy, cerebral ischemia, and anxiety disorders. Awareness of these common clinical patterns increases the likelihood of making a rapid, accurate diagnosis.

Bayesian optimal adaptation explains age-related human sensorimotor changes.

The brain uses information from different sensory systems to guide motor behavior, and aging is associated with simultaneous decline in the quality of sensory information provided to the brain and deterioration in motor control. Correlations between age-dependent decline in sensory anatomical structures and behavior have been demonstrated in many sensorimotor systems, and it has recently been suggested that a Bayesian framework could explain these relationships. Here we show that age-dependent changes in a human sensorimotor reflex, the vestibuloocular reflex, are explained by a Bayesian optimal adaptation in the brain occurring in response to death of motion-sensing hair cells. Specifically, we found that the temporal dynamics of the reflex as a function of age emerge from ( r = 0.93, P < 0.001) a Kalman filter model that determines the optimal behavioral output when the sensory signal-to-noise characteristics are degraded by death of the transducers. These findings demonstrate that the aging brain is capable of generating the ideal and statistically optimal behavioral response when provided with deteriorating sensory information. While the Bayesian framework has been shown to be a general neural principle for multimodal sensory integration and dynamic sensory estimation, these findings provide evidence of longitudinal Bayesian processing over the human life span. These results illuminate how the aging brain strives to optimize motor behavior when faced with deterioration in the peripheral and central nervous systems and have implications in the field of vestibular and balance disorders, as they will likely provide guidance for physical therapy and for prosthetic aids that aim to reduce falls in the elderly. NEW & NOTEWORTHY We showed that age-dependent changes in the vestibuloocular reflex are explained by a Bayesian optimal adaptation in the brain that occurs in response to age-dependent sensory anatomical changes. This demonstrates that the brain can longitudinally respond to age-related sensory loss in an ideal and statistically optimal way. This has implications for understanding and treating vestibular disorders caused by aging and provides insight into the structure-function relationship during aging.

Increased risk of death in community-dwelling older people with white matter hyperintensities on MRI.

BACKGROUND: Previous studies in subjects with a history of stroke have shown that white matter hyperintensities (WMH) on MRI are associated with increased risk of death. However, it has not been determined whether WMH are independently related to death in community-dwelling older people without stroke. METHODS: In a sample of community-dwelling people over 75 years with no history of stroke or other neurological diseases, WMH on brain MRI T2-weighted sequences were classified as grade 0, grade 1, or grade 2. Grade 2 WMH were identified in 36 subjects. Age- and sex-matched grade 0 and grade 1 WMH groups were selected for comparison to the grade 2 WMH group. All subjects underwent an initial clinical evaluation and were followed for a median of 11.8 years (interquartile range=10.7 to 12.2 years). Cox proportional-hazards analysis was used to determine the independent association between WMH and time to death from any cause. RESULTS: In an unadjusted analysis, grade 2 WMH was associated with death from any cause (hazard ratio=1.98; 95% confidence interval=1.06, 3.70). After adjustment for hypertension, high cholesterol, diabetes, and coronary artery disease, grade 2 WMH remained significantly associated with death (hazard ratio=2.31; 95% confidence interval=1.21, 4.40) in these age- and sex-matched groups. CONCLUSIONS: Severe WMH increase the risk of death, even in community-dwelling elderly without stroke or other neurological disease, independent of other covariates including hypertension, age, and coronary artery disease.

Sudden deafness as a sign of stroke with normal diffusion-weighted brain MRI.

Sudden deafness without associated neurological signs and symptoms is typically attributed to a viral inflammation of the labyrinth. Sudden deafness as a heralding manifestation of basilar occlusion has rarely been described. A 60-year-old male with hypertension presented with an acute onset of isolated sudden deafness with vertigo. On admission, initial brain MRI, including diffusion-weighted images, was normal. Two days after the onset of symptoms, the patient presented with an exacerbation of vertigo. A follow-up MRI scan revealed new infarcts involving the right middle cerebellar peduncle, right dorsolateral pons and right anterior cerebellum. In this patient, the acute onset of isolated sudden deafness with vertigo may have been a heralding manifestation of the pontocerebellar infarction.

Hearing symptoms in migrainous infarction.

BACKGROUND: In case reports, migraine headaches have been associated with fluctuating low-frequency hearing loss and sudden, unilateral hearing loss. Auditory symptoms associated with migrainous infarction have not previously been emphasized. OBJECTIVE: To describe migrainous infarction presenting with acute auditory symptoms. DESIGN: Case reports. SETTING: Tertiary care hospitals. PATIENTS: A 40-year-old man with a history of migraine suddenly developed bilateral hearing loss associated with severe, throbbing, occipital headache, tinnitus, vertigo, speech disturbance, and right hemiparesis. An early audiogram showed profound, down-sloping, sensorineural-type hearing loss bilaterally. Sixteen days later, a follow-up pure tone audiogram documented marked improvement in both sides to a pure tone average of 30 dB. Right hemiparesis and dysarthria also improved steadily for 2 months. A 25-year-old woman with a history of migraine with aura suddenly developed hyperacusis, unilateral hearing loss, and migraine headache early in migrainous infarction. Magnetic resonance imaging documented infarcts in the pons and cerebellum. CONCLUSIONS: In these patients, acute auditory symptoms are a part of the prodrome of migrainous infarction. We speculate that these symptoms may have resulted from migraine-associated vasospasm. Migrainous infarction should be considered in the differential diagnosis of acute auditory symptoms, including sudden, bilateral hearing loss.