Among all the clinical indications for which radiologists, nuclear medicine physicians,
neurologists, neurosurgeons, psychiatrists (and others examining disorders of
the brain) order and read brain PET scans, demand is greatest for those pertaining
to dementia and related disorders. This demand is driven by the sheer prevalence of
those conditions, coupled with the fact that the differential diagnosis for causes of
cognitive impairment is wide and often difficult to distinguish clinically.
Restless Legs Syndrome (RLS)
Patients with this sensory-motor disorder report an irresistible urge to move the legs, or sometimes the upper extremities, that is often associated with a creepycrawling or aching dysesthesias deep within the affected limbs. For most patients with RLS, the dysesthesias and restlessness are much worse in the evening or night compared to the daytime and frequently interfere with the ability to fall asleep. The symptoms appear with inactivity and are temporarily relieved by movement.
Drugs Acting on Motor Systems
spinal disorders. Benzodiazepines enhance the effectiveness of the inhibitory transmitter GABA (p. 226) at GABAA receptors. Baclofen stimulates GABAB receptors. !2-Adrenoceptor agonists such as clonidine and tizanidine probably act presynaptically to inhibit release of excitatory amino acid transmitters. The convulsant toxins, tetanus toxin (cause of wound tetanus) and strychnine diminish the efficacy of interneuronal synaptic inhibition mediated by the amino acid glycine (A).
Harrison's Internal Medicine Chapter 27. Aphasia, Memory Loss, and Other Focal Cerebral Disorders
Aphasia, Memory Loss, and Other Focal Cerebral Disorders: Introduction
The cerebral cortex of the human brain contains ~20 billion neurons spread over an area of 2.5 m2. The primary sensory areas provide an obligatory portal for the entry of sensory information into cortical circuitry, whereas the primary motor areas provide final common pathways for coordinating complex motor acts.
The primary sensory and motor areas constitute 10% of the cerebral cortex.
The Parietofrontal Network for Spatial Orientation: Neglect and Related Conditions
Adaptive orientation to significant events within the extrapersonal space is subserved by a large-scale network containing three major cortical components. The cingulate cortex provides access to a limbic-motivational mapping of the extrapersonal space, the posterior parietal cortex to a sensorimotor representation of salient extrapersonal events, and the frontal eye fields to motor strategies for attentional behaviors (Fig. 27-2).
The term parasomnia refers to abnormal behaviors or experiences that arise from or occur during sleep. A continuum of parasomnias arise from NREM sleep, from brief confusional arousals to sleepwalking and night terrors. The presenting complaint is usually related to the behavior itself, but the parasomnias can disturb sleep continuity or lead to mild impairments in daytime alertness. Two main parasomnias occur in REM sleep: REM sleep behavior disorder (RBD), which will be described below, and nightmare disorder.
Increasing numbers of children are recognised as experiencing an autistic
spectrum disorder, and educational provision for most of these children is found
within a mainstream school. Autistic spectrum disorders (ASDs) are also
sometimes referred to as pervasive development disorders because they pervade
so many areas of life and are intrinsic to that individual’s development.
Studies of human movement have proliferated in recent years, and there have been many studies of spinal pathways in humans, their role in movement, and their dysfunction in neurological disorders. This comprehensive reference surveys the literature related to the control of spinal cor
Falls are a common event, particularly among the elderly. Modest changes in balance function have been described in fit older subjects as a result of normal aging. Subtle deficits in sensory systems, attention, and motor reaction time contribute to the risk, and environmental hazards abound.
Epidemiologic studies have identified a number of risk factors for falls, summarized in Table 24-3. A fall is not a neurologic problem, nor reason for referral to a specialist, but there are circumstances in which neurologic evaluation is appropriate.
The GIT motility constituents such as migrating
motor complex in the stomach and the one way peristaltic movements in small
intestine are significantly influenced by the bacterial colonization. Moreover, the
decrease of intestinal motility may cause a small intestinal bacterial overgrowth
Children with disabilities are at risk for experiencing problems in many aspects
of their lives, including becoming independent in daily living skills, meeting
academic expectations, learning to communicate, maintaining emotional and
behavioral regulation, adapting to the social demands of society, and developing
Several studies have shown that deficient uptake or excessive break down
of membrane phospholipids may be associated with neurodegenerative and
psychiatric disorders. The purpose of the present study was to examine the
effects of postnatal iron administration in lipid composition and behavior
and whether or not the established effects may be altered by subchronic
administration of the neuroleptic compounds, clozapine and haloperidol.
Chest pain with dysphagia occurs in DES and related motor disorders. Chest pain resembling DES may occur in esophageal obstruction due to a large bolus. A prolonged history of heartburn and reflux preceding dysphagia indicates peptic stricture. A history of prolonged nasogastric intubation, ingestion of caustic agents, ingestion of pills without water, previous radiation therapy, or associated mucocutaneous diseases may provide the cause of esophageal stricture. If odynophagia is present, candidal, herpes, or pill-induced esophagitis should be suspected.
Lateral (top) and medial (bottom) views of the cerebral hemispheres. The numbers refer to the Brodmann cytoarchitectonic designations. Area 17
.corresponds to the primary visual cortex, 41–42 to the primary auditory cortex, 1– 3 to the primary somatosensory cortex, and 4 to the primary motor cortex. The rest of the cerebral cortex contains association areas.
Not Otherwise Specified [NOS]). We also review functional brain
imaging studies of patients with various forms of conversion disorder (e.g. psychogenic
motor or sensory changes, psychogenic blindness, pseudoseizures) as well as
depersonalization disorder. As hypnotizability traits have been postulated to be associated
with a higher tendency for developing dissociative symptoms, we briefly refer to functional
imaging studies of hypnosis.
Among the swallowing disorders, dysphagia is the most prevalent and dangerous due
to the fact it can lead to tumor formation. The classification of swallowing disorders
into obstructive and non-obstructive including e.g. lower motor neuron dysfunction,
autoimmune disease and achalasia were discussed in this chapter. The authors also
referred to motility disorders in diabetic neuropathy, alcoholism, psychiatric illness
and scleroderma – an autoimmune disease that causes weakening of the tissues of the
Lower Motor Neuron Weakness
This pattern results from disorders of cell bodies of lower motor neurons in the brainstem motor nuclei and the anterior horn of the spinal cord, or from dysfunction of the axons of these neurons as they pass to skeletal muscle (Fig. 232). Weakness is due to a decrease in the number of muscle fibers that can be activated, through a loss of α motor neurons or disruption of their connections to muscle. Loss of γmotor neurons does not cause weakness but decreases tension on the muscle spindles, which decreases muscle tone and attenuates the stretch reflexes...
Hemiparesis results from an upper motor neuron lesion above the midcervical spinal cord; most such lesions are above the foramen magnum. The presence of other neurologic deficits helps to localize the lesion. Thus, language disorders, cortical sensory disturbances, cognitive abnormalities, disorders of visual-spatial integration, apraxia, or seizures point to a cortical lesion. Homonymous visual field defects reflect either a cortical or a subcortical hemispheric lesion.
Paraneoplastic myelitis may present with upper or lower motor neuron symptoms, segmental myoclonus, and rigidity. This syndrome can appear as the presenting manifestation of encephalomyelitis and may be associated with SCLC and serum anti-Hu, anti-CV2/CRMP5, or anti-amphiphysin antibodies. Paraneoplastic myelopathy can also produce several syndromes
characterized by prominent muscle stiffness and rigidity.
James Parkinson described Parkinson’s disease in his memorable Essay on the Shaking Palsy in 1817. Since then,
and particularly in recent years, there has been tremendous progress in our understanding of this complex and fascinating
neurological disorder. Briefly, we have learned that it is not only manifest by motor symptoms but also
that there is a whole range of non-motor features, including autonomic, psychiatric, cognitive and sensory impairments.
We now know how to distinguish better clinically between Parkinson’s disease and the various parkinsonian