Ulegyria
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Ulegyria is a
diagnosis Diagnosis (: diagnoses) is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in a lot of different academic discipline, disciplines, with variations in the use of logic, analytics, and experience, to determine " ...
used to describe a specific type of cortical scarring in the deep regions of the sulcus that leads to distortion of the
gyri In neuroanatomy, a gyrus (: gyri) is a ridge on the cerebral cortex. It is generally surrounded by one or more sulcus (neuroanatomy), sulci (depressions or furrows; : sulcus). Gyri and sulci create the folded appearance of the brain in huma ...
. Ulegyria is identified by its characteristic "mushroom-shaped" gyri, in which scarring causes shrinkage and atrophy in the deep sulcal regions while the surface gyri are spared. This condition is most often caused by
hypoxic-ischemic brain injury Cerebral hypoxia is a form of hypoxia (reduced supply of oxygen), specifically involving the brain; when the brain is completely deprived of oxygen, it is called ''cerebral anoxia''. There are four categories of cerebral hypoxia; they are, in o ...
in the
perinatal period Prenatal development () involves the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal deve ...
. The effects of ulegyria can range in severity, although it is most commonly associated with
cerebral palsy Cerebral palsy (CP) is a group of movement disorders that appear in early childhood. Signs and symptoms vary among people and over time, but include poor coordination, spasticity, stiff muscles, Paresis, weak muscles, and tremors. There may b ...
,
mental retardation Intellectual disability (ID), also known as general learning disability (in the United Kingdom), and formerly mental retardation (in the United States), Rosa's Law, Pub. L. 111-256124 Stat. 2643(2010).Archive is a generalized neurodevelopmental ...
and
epilepsy Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...
. N.C. Bresler was the first to view ulegyria in 1899 and described this abnormal
morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...
in the brain as “mushroom-gyri." Although ulegyria was first identified in 1899, there is still limited information known or reported about the condition.


Anatomy

The physical features of ulegyria consist of small radial scars which occupy the cortical
sulci Sulci or Sulki (in Greek , Stephanus of Byzantium, Steph. B., Ptolemy, Ptol.; , Strabo; , Pausanias (geographer), Paus.), was one of the most considerable cities of ancient Sardinia, situated in the southwest corner of the island, on a small isla ...
. Overall, the physical structure of affected areas in the brain is described as a “mushroom”-like shape in which the
gyri In neuroanatomy, a gyrus (: gyri) is a ridge on the cerebral cortex. It is generally surrounded by one or more sulcus (neuroanatomy), sulci (depressions or furrows; : sulcus). Gyri and sulci create the folded appearance of the brain in huma ...
are unusually large and the sulci become wider deeper in the cortex. N.C. Bresler, the first person to view a brain with ulegyria in 1899, coined the phrase mushroom gyri. He also named the disorder, basing it off the Latin root ''ule'', meaning scar. This mushroom-like structure is the result of the lower parts of the ulegyria-affected area being more prone to deterioration, while the upper gyri are usually spared. However, the entire affected area shrinks and presents brown coloration as a result of ulegyria. In addition, “islands” of neurons that are relatively unaffected can exist between ulegyria affected neurons. Ulegyria can develop bilaterally or unilaterally, though the former is more commonly diagnosed. Ulegyria can affect many parts of the brain including the
cerebral cortex The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. It is the largest site of Neuron, neural integration in the central nervous system, and plays ...
,
parasagittal The sagittal plane (; also known as the longitudinal plane) is an anatomical plane that divides the body into right and left sections. It is perpendicular to the transverse and coronal planes. The plane may be in the center of the body and divid ...
areas and posterior regions of the brain, such as the parietal and
occipital lobe The occipital lobe is one of the four Lobes of the brain, major lobes of the cerebral cortex in the brain of mammals. The name derives from its position at the back of the head, from the Latin , 'behind', and , 'head'. The occipital lobe is the ...
s. These areas are situated either near artery rich regions or near a major
cerebral artery The cerebral arteries describe three main pairs of arteries and their branches, which perfuse the cerebrum of the brain. The three main arteries are the: * ''Anterior cerebral artery'' (ACA), which supplies blood to the medial portion of the bra ...
. For instance, specifically in
neonatal In common terminology, a baby is the very young offspring of adult human beings, while infant (from the Latin word ''infans'', meaning 'baby' or 'child') is a formal or specialised synonym. The terms may also be used to refer to Juvenile (orga ...
children, ulegyria-affected areas are found near the
posterior cerebral artery The posterior cerebral artery (PCA) is one of a pair of cerebral arteries that supply oxygenated blood to the occipital lobe, as well as the medial and inferior aspects of the temporal lobe of the human brain. The two arteries originate from the d ...
or near the artery rich region between the middle and posterior regions of the brain, often referred to as watershed regions. Neurons affected by ulegyria exhibit properties that differ from normally functioning neurons. For instance, ulegyria affected neurons experience
gliosis Gliosis is a nonspecific reactive change of glial cells in response to damage to the central nervous system (CNS). In most cases, gliosis involves the proliferation or hypertrophy of several different types of glial cells, including astrocytes ...
in which
glial cells Glia, also called glial cells (gliocytes) or neuroglia, are non-neuronal cells in the central nervous system (the brain and the spinal cord) and in the peripheral nervous system that do not produce electrical impulses. The neuroglia make up ...
, specifically
astrocytes Astrocytes (from Ancient Greek , , "star" and , , "cavity", "cell"), also known collectively as astroglia, are characteristic star-shaped glial cells in the brain and spinal cord. They perform many functions, including biochemical control of end ...
, build up near and around neurons. Ulegyria affected neurons also display decreases in their
white matter White matter refers to areas of the central nervous system that are mainly made up of myelinated axons, also called Nerve tract, tracts. Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distr ...
content, showing signs of sclerosis, which is characterized by the deterioration of
myelin Myelin Sheath ( ) is a lipid-rich material that in most vertebrates surrounds the axons of neurons to insulate them and increase the rate at which electrical impulses (called action potentials) pass along the axon. The myelinated axon can be lik ...
in neurons. However, in regions of
grey matter Grey matter, or gray matter in American English, is a major component of the central nervous system, consisting of neuronal cell bodies, neuropil ( dendrites and unmyelinated axons), glial cells ( astrocytes and oligodendrocytes), synapses, ...
, large dense aggregates of myelin are present. Ulegyria affected neurons also display metabolic disorders which could be linked to the disease
phenylketonuria Phenylketonuria (PKU) is an inborn error of metabolism that results in decreased metabolism of the amino acid phenylalanine. Untreated PKU can lead to intellectual disability, seizures, behavioral problems, and mental disorders. It may also r ...
and disruptions in the
urea cycle The urea cycle (also known as the ornithine cycle) is a cycle of biochemical reactions that produces urea (NH2)2CO from ammonia (NH3). Animals that use this cycle, mainly amphibians and mammals, are called ureotelic. The urea cycle converts highl ...
.
Hypoglycemia Hypoglycemia (American English), also spelled hypoglycaemia or hypoglycæmia (British English), sometimes called low blood sugar, is a fall in blood sugar to levels below normal, typically below 70 mg/dL (3.9 mmol/L). Whipple's tria ...
and hypoxia are also thought to accompany the symptoms of ulegyria-affected neurons as well.


Causes

Ulegyria develops as a result of a brain injury called
cerebral ischemia Brain ischemia is a condition in which there is insufficient bloodflow to the brain to meet metabolic demand. This leads to poor oxygen supply in the brain and may be temporary such as in transient ischemic attack or permanent in which there is ...
surrounding the time of an infant's birth. Oftentimes, fetal hypoxic-ischemic brain injuries occur as a result of a pregnancy complications such as placental abruption, cord accident, or cardiovascular stress due to a difficult delivery. A lack of oxygen to the brain contributes to the formation of
lesions A lesion is any damage or abnormal change in the tissue of an organism, usually caused by injury or diseases. The term ''Lesion'' is derived from the Latin meaning "injury". Lesions may occur in both plants and animals. Types There is no de ...
usually near the three main
cerebral arteries The cerebral arteries describe three main pairs of artery, arteries and their branches, which perfusion, perfuse the cerebrum of the brain. The three main arteries are the: * ''Anterior cerebral artery'' (ACA), which supplies blood to the medial ...
, located near the
parietal lobe The parietal lobe is one of the four Lobes of the brain, major lobes of the cerebral cortex in the brain of mammals. The parietal lobe is positioned above the temporal lobe and behind the frontal lobe and central sulcus. The parietal lobe integra ...
and
occipital lobes The occipital lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The name derives from its position at the back of the head, from the Latin , 'behind', and , 'head'. The occipital lobe is the visual processing ...
of the
brain The brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for ...
. The cause of perinatal brain injuries includes: :1.
cerebral ischemia Brain ischemia is a condition in which there is insufficient bloodflow to the brain to meet metabolic demand. This leads to poor oxygen supply in the brain and may be temporary such as in transient ischemic attack or permanent in which there is ...
:2.
cerebral hemorrhage Intracerebral hemorrhage (ICH), also known as hemorrhagic stroke, is a sudden bleeding into the tissues of the brain (i.e. the parenchyma), into its ventricles, or into both. An ICH is a type of bleeding within the skull and one kind of stro ...
:3. ascending
intrauterine infections A vertically transmitted infection is an infection caused by pathogenic bacteria or viruses that use mother-to-child transmission, that is, transmission directly from the mother to an embryo, fetus, or baby during pregnancy or childbirth. It can ...
. Some risk factors for perinatal brain injuries include: low birth weight,
preterm birth Preterm birth, also known as premature birth, is the Childbirth, birth of a baby at fewer than 37 weeks Gestational age (obstetrics), gestational age, as opposed to full-term delivery at approximately 40 weeks. Extreme preterm is less than 28 ...
, poor
perinatal Prenatal development () involves the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal deve ...
cardiorespiratory fitness Cardiorespiratory fitness (CRF) refers to the ability of the circulatory and respiratory systems to supply oxygen to skeletal muscles during sustained physical activity. Scientists and researchers use CRF to assess the functional capacity of the ...
, and
artificial ventilation Artificial ventilation or respiration is when a machine assists in a metabolic process to exchange gases in the body by pulmonary ventilation, external respiration, and internal respiration. A machine called a ventilator provides the person air ...
.


Cerebral ischemia

Cerebral ischemia occurs when the brain is not receiving adequate oxygen to continue normal functions. When this occurs, the body makes restoring oxygenated blood flow to life-sustaining organs a priority. The brain alters the diameter of major blood vessels to redistribute blood to key organs such as the brain,
heart The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrie ...
, and
adrenal glands The adrenal glands (also known as suprarenal glands) are endocrine glands that produce a variety of hormones including adrenaline and the steroids aldosterone and cortisol. They are found above the kidneys. Each gland has an outer cortex which ...
. If
sympathetic nervous system The sympathetic nervous system (SNS or SANS, sympathetic autonomic nervous system, to differentiate it from the somatic nervous system) is one of the three divisions of the autonomic nervous system, the others being the parasympathetic nervous sy ...
activation does not produce any improvement, oxygen levels will continue to fall and disruptions to
metabolism Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the co ...
, other cellular processes, and overall functioning will ensue. Another serious result of inefficient blood flow is that cells do not receive adequate amounts of
glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...
. An immediate effect of low intracellular glucose is reduced ATP production in the cell. This effectively inactivates the Na-K pump, leading to the uptake of calcium ions by the cell. Continued influx of calcium serves to constitutively activate downstream effectors, including
lipases In biochemistry, lipase ( ) refers to a class of enzymes that catalyzes the hydrolysis of fats. Some lipases display broad substrate scope including esters of cholesterol, phospholipids, and of lipid-soluble vitamins and sphingomyelinases; how ...
,
proteases A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products. They do ...
, and
endonucleases In molecular biology, endonucleases are enzymes that cleave the phosphodiester bond within a polynucleotide chain (namely DNA or RNA). Some, such as deoxyribonuclease I, cut DNA relatively nonspecifically (with regard to sequence), while many, t ...
, whose actions eventually destroy the cell skeleton. Intracellular calcium concentrations are increased further due to the opening of
glutamate Glutamic acid (symbol Glu or E; known as glutamate in its anionic form) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a Essential amino acid, non-essential nutrient for humans, meaning that ...
-regulated
ion channels Ion channels are pore-forming membrane proteins that allow ions to pass through the channel pore. Their functions include establishing a resting membrane potential, shaping action potentials and other electrical signals by gating the flow of ...
. Ischemia causes
anoxic Anoxia means a total depletion in the level of oxygen, an extreme form of hypoxia or "low oxygen". The terms anoxia and hypoxia are used in various contexts: * Anoxic waters, sea water, fresh water or groundwater that are depleted of dissolved ox ...
cell
depolarizations In biology, depolarization or hypopolarization is a change within a cell (biology), cell, during which the cell undergoes a shift in electric charge distribution, resulting in less negative charge inside the cell compared to the outside. Depolar ...
and it is this increase in
membrane potential Membrane potential (also transmembrane potential or membrane voltage) is the difference in electric potential between the interior and the exterior of a biological cell. It equals the interior potential minus the exterior potential. This is th ...
at the presynaptic cell that triggers the release of
glutamate Glutamic acid (symbol Glu or E; known as glutamate in its anionic form) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a Essential amino acid, non-essential nutrient for humans, meaning that ...
, an excitatory neurotransmitter. Glucose deprivation in the brain for any amount of time has the potential to pose serious consequences, and the amount of time the brain spends under these anoxic conditions is directly related to accumulation of irreversible damage to protein biosynthesis pathways. Protein synthesis all over the body is severely inhibited and essentially comes to a standstill while the brain is suffering from acute
oxygen deprivation Asphyxia or asphyxiation is a condition of deficient supply of oxygen to the body which arises from abnormal breathing. Asphyxia causes generalized hypoxia, which affects all the tissues and organs, some more rapidly than others. There are ma ...
. Once oxygen sufficiently saturates the tissues again, protein biosynthesis returns to normal in non-vulnerable areas but remains at below normal levels in other areas. Insufficient protein synthesis in the brain is especially troubling in the fetal brain given the amount of growth and development that normally occurs. Areas particularly vulnerable to the damaging effects of hypoxic episodes include: the superior
brainstem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is conti ...
, the
cerebellum The cerebellum (: cerebella or cerebellums; Latin for 'little brain') is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as it or eve ...
,
white matter White matter refers to areas of the central nervous system that are mainly made up of myelinated axons, also called Nerve tract, tracts. Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distr ...
and subcortical structures supplied by the branches of deep and superficial penetrating blood vessels. Vulnerable areas where protein synthesis is interrupted usually indicate impending
cell death Cell death is the event of a biological cell ceasing to carry out its functions. This may be the result of the natural process of old cells dying and being replaced by new ones, as in programmed cell death, or may result from factors such as di ...
in
neurons A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural net ...
. When oxygen levels return,
oxygen radicals In chemistry, a radical, also known as a free radical, is an atom, molecule, or ion that has at least one unpaired valence electron. With some exceptions, these unpaired electrons make radicals highly chemically reactive. Many radicals sponta ...
,
nitric oxide Nitric oxide (nitrogen oxide, nitrogen monooxide, or nitrogen monoxide) is a colorless gas with the formula . It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes den ...
and an imbalance of
neurotransmitters A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a synapse. The cell receiving the signal, or target cell, may be another neuron, but could also be a gland or muscle cell. Neurotransmitters are rele ...
cause further damage and lead to cellular death through
apoptosis Apoptosis (from ) is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. Biochemistry, Biochemical events lead to characteristic cell changes (Morphology (biol ...
. Neuron cell death is responsible for
gliosis Gliosis is a nonspecific reactive change of glial cells in response to damage to the central nervous system (CNS). In most cases, gliosis involves the proliferation or hypertrophy of several different types of glial cells, including astrocytes ...
and results in the mushroom appearance of areas and is characteristic of ulegyria.


Cerebral hemorrhage

A
cerebral hemorrhage Intracerebral hemorrhage (ICH), also known as hemorrhagic stroke, is a sudden bleeding into the tissues of the brain (i.e. the parenchyma), into its ventricles, or into both. An ICH is a type of bleeding within the skull and one kind of stro ...
is the result of immature blood vessels of a brain
lesion A lesion is any damage or abnormal change in the tissue of an organism, usually caused by injury or diseases. The term ''Lesion'' is derived from the Latin meaning "injury". Lesions may occur in both plants and animals. Types There is no de ...
bursting. The
germinal matrix In anatomy, the germinal matrix is a highly cellular and highly vascularized region in the brain out from which cells migrate during brain development. The germinal matrix is the source of both neurons and glial cells and is most active between 8 an ...
is a part of the brain that normally disappears as the fetal brain develops but during this process it is not unusual for changes in vessel volume to cause a vessel to burst. According to recent microscopic studies, the most common location for a cerebral hemorrhage is where the medullary veins drain to the terminal vein in the sub-
ependymal The ependyma is the thin neuroepithelial ( simple columnar ciliated epithelium) lining of the ventricular system of the brain and the central canal of the spinal cord. The ependyma is one of the four types of neuroglia in the central nervous sys ...
region. It has been hypothesized that because pre-term babies don't have fully developed sympathetic nervous systems, they cannot react as well to low oxygen saturation levels caused by the cerebral hemorrhage. Although babies born at full-term are still susceptible to this, they are likely to respond better and thus, tend to have better outcomes in response to low-oxygen events.


Ascending intrauterine infections

Recent research has found a connection between
intrauterine infections A vertically transmitted infection is an infection caused by pathogenic bacteria or viruses that use mother-to-child transmission, that is, transmission directly from the mother to an embryo, fetus, or baby during pregnancy or childbirth. It can ...
and inflammation in the mother and an increased likelihood of
perinatal Prenatal development () involves the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal deve ...
brain damage in the fetus. This study suggested that intrauterine infections in the mother could affect
glial cells Glia, also called glial cells (gliocytes) or neuroglia, are non-neuronal cells in the central nervous system (the brain and the spinal cord) and in the peripheral nervous system that do not produce electrical impulses. The neuroglia make up ...
and
toll-like receptors Toll-like receptors (TLRs) are a class of proteins that play a key role in the innate immune system. They are single-pass membrane protein, single-spanning receptor (biochemistry), receptors usually expressed on sentinel cells such as macrophages ...
(TLRs) which are important in moderating the inflammatory response in the fetal brain. When
glial cells Glia, also called glial cells (gliocytes) or neuroglia, are non-neuronal cells in the central nervous system (the brain and the spinal cord) and in the peripheral nervous system that do not produce electrical impulses. The neuroglia make up ...
and TLRs are negatively affected they are not able to react to developing inflammation in the brain as well. The connection between ascending intrauterine infections and perinatal brain damage is a developing research theory but a more detailed explanation of the connection is not yet known.


Signs and symptoms

Ulegyria was found in about 1/3 of patients with defects caused by circulatory disease in the
perinatal period Prenatal development () involves the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal deve ...
. Most clinical observations of the condition report mental retardation, cerebral palsy, and seizures as the main defects. However, milder cases have been reported in which patients that exhibit ulegyria develop relatively normally. The main movement disorders associated with ulegyria that are classified as cerebral palsy are
choreoathetosis Choreoathetosis is the occurrence of involuntary movements in a combination of chorea (irregular migrating contractions) and athetosis (twisting and writhing). It is caused by many different diseases and agents. It is a symptom of several disease ...
,
dystonia Dystonia is a neurology, neurological Hyperkinesia, hyperkinetic Movement disorders, movement disorder in which sustained or repetitive muscle contractions occur involuntarily, resulting in twisting and repetitive movements or abnormal fixed po ...
, and
ataxia Ataxia (from Greek α- negative prefix+ -τάξις rder= "lack of order") is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in e ...
. It is suspected that ulegyria leads to
epilepsy Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...
because malformation of the cortex obstructs the differentiation of neurons, glial cells, and
synapses In the nervous system, a synapse is a structure that allows a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or a target effector cell. Synapses can be classified as either chemical or electrical, depending o ...
. Parietal-
occipital The occipital bone () is a cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone lies over the occipital lobes of the cere ...
lobe
epilepsy Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...
, which is often synonymous with
posterior cortex Posterior cortex usually means the posterior (back) part of the complete cerebral cortex and includes the occipital, parietal, and temporal cortices. In other words, the posterior cortex includes all the cerebral cortex without the frontal corte ...
epilepsy (PCE), is the form of the disease seen in most cases involving ulegyria. This type of epilepsy is very rare, making up about 5% of all reports of epilepsy. This form of the disease involves symptoms that would be expected from damage to the parietal and occipital lobes: seizures with visual hallucinations, visuospatial dysfunction, tingling, numbness, pain, and a burning sensation. In addition to ulegyria, tumors and
cortical dysplasia Focal cortical dysplasia (FCD) is a congenital abnormality of brain development where the neurons in an area of the brain failed to migrate in the proper formation ''in utero''. ''Focal'' means that it is limited to a focal zone in any lobe. Foca ...
constitute the major causes of PCE. Most of the epilepsy seen in conjunction with ulegyria is classified as medically refractory, meaning it is not responsive to treatment. Patients usually present symptoms of epilepsy at an early age. The severity of epilepsy has been shown to depend on this age of onset as well as the quantity of cortical lesions; earlier onset of epilepsy and a larger extent of lesions tends to mean more severe seizures.


Similar conditions

Ulegyria is often confused with a similar distortion of the
cortex Cortex or cortical may refer to: Biology * Cortex (anatomy), the outermost layer of an organ ** Cerebral cortex, the outer layer of the vertebrate cerebrum, part of which is the ''forebrain'' *** Motor cortex, the regions of the cerebral cortex i ...
known as
polymicrogyria Polymicrogyria (PMG) is a condition that affects the development of the human brain by multiple small gyri ( microgyri) creating excessive folding of the brain leading to an abnormally thick cortex. This abnormality can affect either one region of ...
. Polymicrogyria is characterized by excessive folding of the surface
gyri In neuroanatomy, a gyrus (: gyri) is a ridge on the cerebral cortex. It is generally surrounded by one or more sulcus (neuroanatomy), sulci (depressions or furrows; : sulcus). Gyri and sulci create the folded appearance of the brain in huma ...
and a thickening of the
cerebral cortex The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. It is the largest site of Neuron, neural integration in the central nervous system, and plays ...
, rather than the sulcal scarring that is typical of ulegyria. In addition to morphological differences, the period in which polmicrogyria and ulegyria emerge is also different. Polymicrogyria typically forms while the embryo's
central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity o ...
is maturing. Ulegyria is acquired later in development during the
perinatal period Prenatal development () involves the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal deve ...
after
neuronal migration The development of the nervous system, or neural development (neurodevelopment), refers to the processes that generate, shape, and reshape the nervous system of animals, from the earliest stages of embryonic development to adulthood. The field ...
has already occurred. It is also suspected that polymicrogyra is genetically linked, whereas ulegyria is caused by environmental factors—namely lack of oxygen. Polymicrogyria can lead to similar conditions that are linked to ulegyria such as
mental retardation Intellectual disability (ID), also known as general learning disability (in the United Kingdom), and formerly mental retardation (in the United States), Rosa's Law, Pub. L. 111-256124 Stat. 2643(2010).Archive is a generalized neurodevelopmental ...
,
cerebral palsy Cerebral palsy (CP) is a group of movement disorders that appear in early childhood. Signs and symptoms vary among people and over time, but include poor coordination, spasticity, stiff muscles, Paresis, weak muscles, and tremors. There may b ...
, and
epilepsy Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...
. It has been observed that patients with polymicrogyria are not receptive to
epilepsy surgery Epilepsy surgery involves a neurosurgery, neurosurgical procedure where an area of the brain involved in seizures is either resected, ablative brain surgery, ablated, disconnected or stimulated. The goal is to eliminate seizures or significantly ...
. However, responses of patients with ulegyria to similar surgeries are still not fully known, which makes distinction of these two disorders significant. In vivo neuroimaging techniques, namely
MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and rad ...
, have been instrumental in making this distinction. An MRI image of ulegyria is identified by mushroom shaped gyri, deformities in white matter, and localization mainly in the posterior cerebral region. Polymicrogyria is typically recognized by a scalloped appearance at the bordering region between grey and white matter. Although these distinctions have been made with many patients, there is still some difficulty in defining distinct boundaries between these two similar conditions.


Detection

Primarily, the main method of detecting ulegyria is through the use of
MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and rad ...
screening for epilepsy. Normally an MRI of an ulegyria affected region will reveal groups of deteriorated neurons with gliosis present. In addition, unaffected gyri are also present in especially bilateral watershed regions indicating delayed effects of perinatal hypoxic damage. However, there are three main criteria for diagnosing ulegyria using MRI in addition to the features mentioned above: :1.The presence of a poorly demarcated lesion :2.
Atrophy Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations (which can destroy the gene to build up the organ), malnutrition, poor nourishment, poor circulatory system, circulation, loss of hormone, ...
and thinning of the cortex resulting in the characteristic “mushroom” like shape of ulegyria. :3. Presence of white matter signal abnormalities as a result of FLAIR signaling (fluid attenuated inversion recovery). Another sign of ulegyria that is visible on an MRI scan is the presence of a widened subarachnoid space, signifying cortex atrophy. FLAIR signaling can help visualize the depths of the parietal-occipital sulci, which also allows ulegyria-affected gyri to be identified. Though there is still confusion in differentiating ulegyria and polymicrogyria in patients, MRI allows for the proper identification in the majority of the cases. In addition, most of the current research regarding ulegyria is focused on improving this identification. Furthermore, MRI can diagnose whether ulegyria presence is unilateral or bilateral. Electroencephalography,
EEG Electroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. The bio signals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neoc ...
, can also be used to screen for ulegyria, though MRI is still preferred. This is mainly done for epilepsy patients as abnormalities in EEG recordings indicate the presence of ulegyria in the area of the brain being tested. For example, when EEG tests in epileptic patients show deviations in the frontal and central-parietal regions, ulegyria can be considered to be present in that area.


Treatment

Presently, there is no well-defined treatment for ulegyria mainly because of the irreversible
ischaemic Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems ...
damage done to neurons of an affected area. However, conditions associated with ulegyria, such as
epilepsy Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...
and
cerebral palsy Cerebral palsy (CP) is a group of movement disorders that appear in early childhood. Signs and symptoms vary among people and over time, but include poor coordination, spasticity, stiff muscles, Paresis, weak muscles, and tremors. There may b ...
, can be treated using the appropriate treatment. For instance, seizures caused by epilepsy, due to the presence of ulegyria in the
occipital lobe The occipital lobe is one of the four Lobes of the brain, major lobes of the cerebral cortex in the brain of mammals. The name derives from its position at the back of the head, from the Latin , 'behind', and , 'head'. The occipital lobe is the ...
, can be controlled using
antiepileptic Anticonvulsants (also known as antiepileptic drugs, antiseizure drugs, or anti-seizure medications (ASM)) are a diverse group of pharmacological agents used in the treatment of epileptic seizures. Anticonvulsants are also used in the treatmen ...
drugs in some patients. In other patients, such as those who suffer from ulegyria in the
posterior cortex Posterior cortex usually means the posterior (back) part of the complete cerebral cortex and includes the occipital, parietal, and temporal cortices. In other words, the posterior cortex includes all the cerebral cortex without the frontal corte ...
, drugs are not effective and
surgery Surgery is a medical specialty that uses manual and instrumental techniques to diagnose or treat pathological conditions (e.g., trauma, disease, injury, malignancy), to alter bodily functions (e.g., malabsorption created by bariatric surgery s ...
of the area causing epilepsy is needed. These treatments treat only the conditions but have no effect on the condition of ulegyria itself.


References

{{Reflist, colwidth=35em Cerebrum Neuropathology