Gerstmann syndrome is a rare neurological disorder characterized by a notebook of clinical manifestations, including counting disorder, agraphy, apraxia, spatial orientation disorder (“right”, “left”). These symptoms are detected by special neuropsychological testing. The final diagnosis is made based on the results of CT, MRI, and brain angiography. Pharmacotherapy is carried out with nootropic, neuroprotective, vascular drugs. Neoplasms, vascular anomalies are subject to surgical treatment.
ICD 10
F81.2 Specific disorder of arithmetic skills
General information
Gerstmann syndrome (angular gyrus syndrome) was first mentioned by the French doctor J. Badalem in 1888 A detailed study of the pathology was carried out by the neurologist Joseph Gerstman in 1924-1930. Previously, the synonymous name — angular syndrome was used. Among the patients there are people of different age categories, no sex differences in the incidence rate were found. Gerstmann syndrome has also been described in children with learning disabilities. Incomplete variants of the lesion of the angular gyrus are often found, limited to 2-3 symptoms, full forms are extremely rare.
Causes
Gerstman’s clinical tetrad occurs when the angular gyrus of the dominant hemisphere is damaged, located in the posterior parietal region on the border with the temporal and occipital lobes. The damage can be traumatic in nature, be a consequence of various pathological processes of cerebral localization or diffuse nature. The main etiofactors of the disease in clinical neurology are:
- Vascular disorders. These include stenosis or aneurysm of the carotid artery, damage to the middle cerebral artery, and other disorders of the cerebral blood supply in the area of the angular gyrus. Gerstmann syndrome is observed in an ischemic stroke clinic of the appropriate localization.
- Cerebral tumors. The location of the tumor is crucial. Possible germination of the angular gyrus by tumor cells, its compression by a nearby neoplasm.
- Degenerative diseases of the brain. Gerstmann syndrome is observed in some cases of multiple sclerosis, progressive multifocal leukoencephalopathy, cortical atrophy. Demyelination, atrophy of the nervous tissue of the angular gyrus entail the loss of the functions performed by it.
- Traumatic brain injuries. Mechanical damage, compression of brain tissues by the resulting post-traumatic hematoma leads to the disintegration of various cortical zones with the development of the disease.
- Intoxication. Alcoholism, carbon monoxide poisoning, lead intoxication lead to toxic-hypoxic damage to brain tissues. The selective localization of the disorders that causes the Gerstman tetrad of this etiology remains unclear.
- Iatrogenia. Rare cases of the syndrome were noted as a complication of cerebral angiography, endovascular elimination of arteriovenous malformation, acetazolamide therapy.
Pathogenesis
In the dominant hemisphere, the angular gyrus is the intersection of the pathways connecting the visual center located in the occipital lobe, the temporal speech zone of Wernicke and the motor center of the upper limb. Variable etiological factors that cause damage, demyelination, and atrophic changes in this area lead to the disintegration of these centers.
The ability to understand speech, writing, and counting is the result of the joint work of visual, speech, and motor analyzers and suffers from a violation of the connections between them. The disorder of simultaneous synthesis of information entering the brain from the peripheral parts of the analyzers entails a partial violation of gnosis, affecting the perception of the fingers of the hand, the concepts of “right” and “left”. The incomplete variant of pathology is due to the partial preservation of some connections sufficient to provide a separate function.
Histopathological data are variable. Vascular ischemic lesions are characterized by neuron necrosis. For neoplasms, invasive growth or compression lesion of the angular region is typical. Necrotizing granulomatous inflammation of small and medium-sized subarachnoid vessels, expansion of perivascular spaces with multiple cystic lesions is possible.
Symptoms
The classic notebook of signs of Gerstmann syndrome is: acalculia, dysgraphy, right-left disorientation, finger agnosia. Acalculia is manifested by the inability to perform elementary arithmetic calculations while maintaining an understanding of numbers. Acalculia is always associated with semantic aphasia. The patient’s speech is simplified, filled with agrammatism. It is difficult to perceive complex elements of speech: speech turns, cause-and-effect constructions.
The disorder of writing is characterized by multiple errors, paragraphs, omissions of words. Agnosia is expressed in difficulties with the differentiation of the fingers of the hand: patients cannot show the named finger on their own hand and name the finger of the researcher shown to them. The patient does not understand where the “right” and “left” are, which also leads to a violation of the body scheme in the form of the inability to divide the parts of his own body into right and left. A distinctive feature is the presence of these symptoms against the background of the cognitive safety of the patient.
A number of clinicians distinguish Gerstman’s development cider, detected in children at the beginning of school. Such students are distinguished by poor handwriting, spelling problems and lack of ability to master simple mathematical skills. Often they have difficulties not only with writing, but also with reading words.
Diagnostics
The diagnosis of Gerstmann syndrome is established when a complex of characteristic symptoms is detected during a thorough neurological and neuropsychological examination. Finger agnosia is detected in the dominant hand. Evaluating the results of the study, it is necessary to take into account the presence of tactile sensitivity disorders. Right-left orientation testing is performed separately, including the patient’s instructions in written and oral form.
To identify dysgraphy, the patient is asked to write down individual words and sentences independently, from the proposed text, under dictation. Arithmetic testing diagnoses the safety of visual-auditory recognition of digits, the inability to perform calculations.
Patients with Gerstmann syndrome must undergo an instrumental examination to determine the nature of the pathological process that caused the syndrome. The list of ongoing studies includes the following neuroimaging methods:
- CT scan of the brain. It allows to diagnose intracranial volumetric formations, structural anomalies, post-traumatic hematomas. The ischemic focus is visualized as a low-density area. In patients with chronic subdural hematoma, extraaxial hypodensive accumulation of fluid is detected.
- Brain MRI. It is more informative in the diagnosis of ischemic disorders, degenerative processes of the angular gyrus. Allows you to estimate the prevalence of the process. Multiple sclerosis is characterized by the presence of plaques on MRI images, leukoencephalopathy — abnormal hyperintensive foci on T2-weighted images.
- Brain angiography. It is carried out if the vascular etiology of Gerstmann syndrome is suspected. Diagnoses vascular anomalies, vascular wall lesion, stenosis. Areas of decreased cerebral blood flow correspond to the localization of ischemic foci according to MRI data.
Differential diagnosis
Components of Gerstmann syndrome can be symptoms of mental disorder and cognitive impairment. The exclusion of mental illnesses, such as schizophrenia, psychopathy, psychosis, dementia, is carried out by a psychiatrist.
In children’s patients, it is necessary to differentiate the Gerstman phenomenon with a violation of intellectual development. A distinctive feature of the latter is the disorder of all cognitive functions equally, the inability to think figuratively, a decrease in the ability to make decisions, poor speech. Special attention is paid to the differentiation of etiological types of Gerstmann syndrome, since it is of decisive importance in the choice of therapeutic tactics.
Treatment
Therapy depends on the etiology of the process. Along with pharmacotherapy, corrective treatment aimed at improving writing, counting, and gnostic functions is necessary. In some cases, neurosurgical surgery is required to eliminate the pathological focus. The medication prescribed by a neurologist may include:
- Vascular therapy. Includes products that improve cerebral blood flow. Drugs of the thrombolytic group, vasodilators, improving microcirculation are used.
- Neuroprotective therapy. Neuroprotectors increase the resistance of neurons to pathological conditions resulting from the action of any etiological factor. They allow to preserve the metabolism and functional activity of the nervous tissue.
- Nootropic treatment. It is carried out with the use of pharmaceuticals that stimulate the work of neurons and the functioning of interneuronal messages. Improves the cognitive abilities of the patient.
- Detoxification. Toxic brain damage requires urgent detoxification measures in the form of intravenous drip administration of solutions and sorbents. Timely elimination of the effects of the toxic factor prevents the development of irreversible changes in the angular region.
Surgical treatment
Indications for surgery are cerebral tumors, vascular malformations, posttraumatic hematomas. Most operations are carried out as planned, after careful weighing of the need for intervention. In the postoperative period, drug treatment with neuroprotectors and nootropics is carried out. Rehabilitation is mandatory, including regular classes to restore praxis, writing, and the ability to count.
Prognosis and prevention
The outcome of Gerstmann syndrome depends on its etiology, the age of the patient, and the timeliness of professional treatment. The rapid elimination of intoxication leads to the restoration of cerebral functions. Chronic intoxication, irreversible degenerative processes gradually lead to the aggravation of the disease. However, timely and regular treatment can slow down the progression of pathology. The result of surgical treatment is a partial restoration of abilities. Correctional therapy is more successful in children, it allows to improve counting, writing, and reduce apraxia.
Prevention of Gerstmann syndrome includes the exclusion of mutagenic factors leading to the development of neoplasms, proper nutrition and regular motor activity to prevent vascular diseases, injury prevention.