Gerstmann syndrome

# Overview
Gerstmann syndrome is a rare neurological disorder that is characterized by a tetrad of symptoms which include finger agnosia, agraphia, acalculia, and left - right disorientation. Also known as Angular gyrus syndrome as it occurs due to lesion or pathology involving the angular gyrus of the inferior parietal lobule extending to the subcortical white matter in the dominant hemisphere. Developmental Gerstmann syndrome, a variant described in children is a neurodevelopmental disorder, includes the tetrad along with constructional dyspraxia as the fifth clinical symptom. (It should not be confused with Gerstmann-Straussler syndrome, which is a transmissible spongiform encephalopathy.)

# Pathophysiology
The clinical feature of Gerstmann syndrome can be explained by lesions involving specific areas of brain, but there has been several disagreements among the researchers about the true existence of syndrome and its exact localization.
It was observed that the symptoms were due to defective transformation or mental manipulation of images which was supported by many researchers. Studies also noted that a defect in horizontal transition i.e. mental spatial rotation accounted for left - right disorientation, finger agnosia, acalculia and their simultaneous occurrence was not coincidental, but a part of clinical syndrome.
Finger agnosia and acalculia were localized to supramarginal gyrus close to parietal sulcus and lesion extending to superior parietal gyrus caused apraxic agraphia. Some studies also reported the involvement of Left middle frontal lobe in Gerstmann syndrome It was proposed that a focal lesion in the left parietal white matter, involves the various crossing fibre tract, thus disconnecting the separate cortical networks, causing the pure form of Gerstmann syndrome i.e without aphasia. The etiology of developmental gerstmann syndrome is unknown and several hypotheses were proposed but none of them were confirmed.

# Causes
As the syndrome was localized to specific areas in the brain, any lesion or pathology involving those areas can cause Gerstmann syndrome. These include but not limited to
- Tumors
- Ischemic stroke involving MCA region
- MCA aneurysm
- Cortical atrophy
- Multiple sclerosis
- Chronic Subdural hematoma
- SLE
- Lead, CO poisoning
- Traumatic brain injury
- Alcoholism
- Anaphylactic shock
- Brain Abscess
The etiology of developmental Gerstmann syndrome is unknown. It was thought to be associated with perinatal brain injury, but the syndrome was also observed in children without any signs of brain injury

# Primary symptoms
Gerstmann syndrome is characterized by four primary symptoms:
- Dysgraphia/agraphia
- Dyscalculia/acalculia
- Finger agnosia
- Left-right disorientation

# Causes
This disorder is often associated with brain lesions in the dominant (usually left) side of the  angular and  supramarginal gyri near the  temporal and parietal lobe junction.  There is significant debate in the scientific literature as to whether Gerstmann Syndrome truly represents a unified, theoretically motivated syndrome.  Thus its diagnostic utility has been questioned by neurologists and neuropsychologists alike.

# In adults
In adults, the syndrome may occur after a stroke or in association with damage to the parietal lobe.
In addition to exhibiting the above symptoms, many adults also experience aphasia, which is a difficulty in expressing oneself when speaking, in understanding speech, or in reading and writing.

# In children
There are few reports of the syndrome, sometimes called developmental Gerstmann syndrome, in children. The cause is not known. Most cases are identified when children reach school age, a time when they are challenged with writing and math exercises. Generally, children with the disorder exhibit poor handwriting and spelling skills, and difficulty with math functions, including adding, subtracting, multiplying, and dividing. An inability to differentiate right from left and to discriminate among individual fingers may also be apparent. In addition to the four primary symptoms, many children also suffer from constructional apraxia, an inability to copy simple drawings. Frequently, there is also an impairment in reading. Children with a high level of intellectual functioning as well as those with brain damage may be affected with the disorder.

# Treatment
There is no cure for Gerstmann syndrome. Treatment is symptomatic and supportive. Occupational and speech therapies may help diminish the dysgraphia and apraxia. In addition, calculators and word processors may help school children cope with the symptoms of the disorder.

# Prognosis
In adults, many of the symptoms diminish over time. Although it has been suggested that in children symptoms may diminish over time, it appears likely that most children probably do not overcome their deficits, but learn to adjust to them.

# Sources
- Template:NINDS