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Ocular Functional and Structural Investigations

Functional and structural investigations that assess the integrity of the visual system are of utmost importance for diagnosing and monitoring ophthalmic or neurological disorders that affect vision. These investigations complement the ophthalmic and fundus examinations, allowing precise quantitative baseline and serial assessments. Structural investigations include fundus imaging, fluorescein angiography (FA), optical coherence tomography (OCT) imaging, and orbital ultrasound. Functional investigations include assessment of the visual field…

Functional and Molecular Neuroimaging

Structural imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI) are essential techniques for evaluating various central nervous system (CNS) disorders, providing superb structural resolution and tissue contrast. On the other hand, functional and molecular imaging modalities—such as functional MRI (fMRI), positron emission tomography (PET), and single-photon emission computed tomography (SPECT)—visualize brain functions that are not necessarily related to brain structure, most notably…

Vascular Imaging: Computed Tomographic Angiography, Magnetic Resonance Angiography, and Ultrasound

Computed Tomographic Angiography Computed tomographic angiography (CTA) is a relatively rapid, thin-section, volumetric, helical CT technique performed with a time-optimized bolus of contrast medium to enhance visualization of the cerebral circulation. This approach may be tailored to illustrate various segments of the circulation, from arterial segments to the venous system. The ongoing development of multidetector CT scanners has advanced CTA, with increasing numbers of detectors used…

Structural Imaging Using Magnetic Resonance Imaging and Computed Tomography

Computed Tomography Computed tomography (CT; other terms include computer assisted tomography [CAT]) has been commercially available since 1973. The term tomography (i.e., to slice or section) refers to a process for generating two-dimensional (2D) image slices of an examined organ of three dimensions (3D). CT imaging is based on the differential absorption of x-rays by various tissues. X-rays are electromagnetic waves with wavelengths falling in the…

Intraoperative Monitoring

Neurophysiological intraoperative monitoring (IOM) uses electroencephalography (EEG), electromyography (EMG), and evoked potentials (EPs) during surgery to improve outcome. These techniques warn the surgeon of impending complications in time to intervene and correct problems before they become worse. IOM can also identify motor or language cortex to spare them from resection. A surgeon can rely on monitoring for reassurance about nervous system integrity, allowing the surgery to…

Intracranial Neuromodulation

As early as the 1950s temporary deep brain stimulation (DBS) electrodes were implanted into the septal region. The procedure was performed for pain control and was reported to have beneficial effects ( ). There were various attempts at DBS, with most documented experiences revealing its usefulness in test stimulation prior to ablative brain lesions ( ). In 1987, when Alim-Louis Benabid was operating on a chronic…

Extracranial Neuromodulation

At the beginning of the 1980s, Merton and Morton developed the first method of noninvasive brain stimulation, transcranial electrical stimulation (TES), and this had obvious clinical application. They used a single, brief, high-voltage electric shock and produced a relatively synchronous muscle response, the motor evoked potential (MEP). The latency of MEPs was compatible with activation of the fast-propagating corticospinal tract. It was immediately clear that this…

Clinical Electromyography

Clinical electromyography is a distinct medical discipline that plays a pivotal role in the diagnosis of peripheral nerve and neuromuscular disorders ( ). The designations clinical electromyography (EMG) , electrodiagnostic (EDX) examination , and electroneuromyography (ENMG) are used interchangeably to encompass the electrophysiological study of peripheral nerve, neuromuscular junction, and muscle; the terms needle electromyography and needle electrode examination are reserved for the specific testing that…

Electroencephalography and Evoked Potentials

The techniques of applied electrophysiology are of practical importance in diagnosing and managing certain categories of neurological disease. Modern instrumentation permits the selective investigation of the functional aspects of the central and peripheral nervous systems. The electroencephalogram (EEG) and evoked potentials are measures of electrical activity generated by the central nervous system (CNS). Despite the introduction of positron emission tomography (PET), functional magnetic resonance imaging (fMRI),…

Investigations in the Diagnosis and Management of Neurological Disease

The history and examination are key to making the diagnosis in a patient with neurological disease (see Chapter 1 ). However, ancillary testing is very important in diagnosis and management. Testing for specific disorders is addressed in detail in later chapters in Part III. This chapter provides a general overview of the principles that underlie obtaining investigations beyond the neurological examination. Investigations beyond the history and…

Lower Back and Lower Limb Pain

Lower back pain is one of the most common reasons for neurological and neurosurgical consultation. In many of the patients who present with lower back pain, the pain either developed or was exacerbated as a result of occupational activity. Lower limb pain is a common accompaniment to lower back pain but can occur independently. The list of considerations in the differential diagnosis of lower back and…

Arm and Neck Pain

Evaluation of the patient with arm and/or neck pain is based on a meticulous history and clinical examination. A useful approach is to consider the diagnosis in terms of pain-sensitive structures in the neck and upper limbs. These structures may be part of the nervous system or may involve joints, muscles, and tendons. Neurological causes of pain should be considered based on the innervation of the…

Sensory Abnormalities of the Limbs, Trunk, and Face

Clinical evaluation of sensory deficits is inherently more difficult than evaluation of motor deficits because of the subjective nature of the examination. Nevertheless, it is important to identify sensory deficits in order to localize lesions. Anatomy and Physiology Peripheral Pathways Activation of sensory end organs produces a generator potential in the afferent neurons. If the generator potential reaches threshold, an action potential is produced that is…

Hypotonic (Floppy) Infant

A floppy, or hypotonic, infant is a common scenario encountered in the clinical practice of child neurology. It can present significant challenges in terms of localization and is associated with an extensive differential diagnosis ( Box 30.1 ). As with any clinical problem in neurology, attention to certain key aspects of the history and examination allows correct localization within the neuraxis and narrows the list of…

Muscle Pain and Cramps

General Features of Pain Pain is an uncomfortable sensation with sensory and emotional components. Short episodes of pain or discomfort localized to muscle are a near universal experience. Common causes of short-term muscle discomfort are unaccustomed exercise, trauma, cramps, and systemic infections. Pain localized to muscle may be due to noxious stimuli in muscle or referral from other structures including skin, nerves, connective tissue, joints, and…

Proximal, Distal, and Generalized Weakness

Muscle weakness may be due to disorders of the central nervous system (CNS) or peripheral nervous system (PNS). The PNS includes the primary sensory neurons in the dorsal root ganglia, nerve roots, peripheral nerves, neuromuscular junctions, and muscles. Although not strictly peripheral, the primary motor neurons (anterior horn cells) in the brainstem and spinal cord are also conventionally included as part of the PNS. The neurological…

Paraplegia and Spinal Cord Syndromes

Paraplegia and quadriplegia may result from a variety of systemic and primary central nervous system medical conditions as well as trauma at all segmental levels of the spinal cord ( Box 27.1 ). A spinal cord syndrome may develop from extramedullary and intramedullary pathological processes. Initial symptoms may be gradual in onset and progressive, including pain, dysesthesia, or subtle upper or lower extremity weakness. In other…

Hemiplegia and Monoplegia

Hemiplegia and monoplegia are more likely to be due to discrete focal lesions than diffuse lesions, so these presentations are especially suited to clinical-anatomical localization. Similarly, imaging studies are likely to be revealing with hemiplegia or monoplegia, but the focus of imaging must be directed by clinical suspicion. Hemiplegia and monoplegia are motor symptoms and signs; however, associated sensory abnormalities are essential to localization, so these…

Gait Disorders

The maintenance of an upright posture and the act of walking are among the first and ultimately most complex motor skills humans acquire. From an early age, walking skills are modified and refined. In later years, the interplay between voluntary and automatic control of posture and gait provides a rich and complex repertoire of motion that ranges from walking and running to complex sports and dancing.…

Diagnosis and Assessment of Parkinson Disease and Other Movement Disorders

The term movement disorders is often used synonymously with basal ganglia or extrapyramidal diseases . However, neither of the two latter terms adequately encompasses all the disorders included under the broad umbrella of movement disorders. Movement disorders are neurological motor disorders manifested by slowness or poverty of movement (bradykinesia or hypokinesia, such as that seen in parkinsonian disorders) at one end of the spectrum and abnormal…