Electrophysiologic testing is an essential part of the evaluation of Anterior interosseous nerve syndromes. Nerve conduction studies may be normal or show pronator quadratus latency.⁠⁠

Electromyography (EMG) is generally most useful and will reveal abnormalities in the flexor pollicis longus, flexor digitorum profundus I and II and pronator quadratus muscles.⁠⁠

The role or MRI and ultrasound imaging in the diagnosis of Kiloh-Nevin syndrome is unclear.⁠

If asked to make the "OK" sign, patients will make a triangle sign instead.

This 'Pinch-Test' exposes the weakness of the Flexor pollicis longus muscle and the flexor digitorum profundus I leading to weakness of the flexion of the distal phalanges of the thumb and index finger. This results in impairment of the pincer movement and the patient will have difficulty picking up a small item, such as a coin, from a flat surface.

EMG test is often performed together with another test called nerve conduction study, which measures the conducting function of nerves. NCV study shows loss of nerve conduction in the distal segment (3 to 4 days after injury). According to NCV study, in axonotmesis there is an absence of distal sensory-motor responses.

Electromyography (EMG) is a medical test performed to evaluate and record the electrical activity (electromyogram) produced by skeletal muscles using an instrument called electromyograph. In axonotmesis, EMG changes (2 to 3 weeks after injury) in the denervated muscles include:

1. Fibrillation potentials (FP)

2. Positive sharp waves

Radiculopathy is a diagnosis commonly made by physicians in primary care specialities, chiropractic, orthopedics, physiatry, and neurology. The diagnosis may be suggested by symptoms of pain, numbness, and weakness in a pattern consistent with the distribution of a particular nerve root. Neck pain or back pain may also be present. Physical examination may reveal motor and sensory deficits in the distribution of a nerve root. In the case of cervical radiculopathy, Spurling's test may elicit or reproduce symptoms radiating down the arm. In the case of lumbosacral radiculopathy, a Straight leg raise maneuver may exacerbate radiculopathic symptoms. Deep tendon reflexes (also known as a Stretch reflex) may be diminished or absent in areas innervated by a particular nerve root.

For further workup, the American College of Radiology recommends that projectional radiography is the most appropriate initial study in all patients with chronic neck pain. Two additional diagnostic tests that may be of use are magnetic resonance imaging and electrodiagnostic testing. Magnetic resonance imaging (MRI) of the portion of the spine where radiculopathy is suspected may reveal evidence of degenerative change, arthritic disease, or another explanatory lesion responsible for the patient's symptoms. Electrodiagnostic testing, consisting of NCS (Nerve conduction study) and EMG (Electromyography), is also a powerful diagnostic tool that may show nerve root injury in suspected areas. On nerve conduction studies, the pattern of diminished Compound muscle action potential and normal sensory nerve action potential may be seen given that the lesion is proximal to the Posterior root ganglion. Needle EMG is the more sensitive portion of the test, and may reveal active denervation in the distribution of the involved nerve root, and neurogenic-appearing voluntary motor units in more chronic radiculopathies. Given the key role of electrodiagnostic testing in the diagnosis of acute and chronic radiculopathies, the American Association of Neuromuscular & Electrodiagnostic Medicine has issued evidence-based practice guidelines, for the diagnosis of both cervical and lumbosacral radiculopathies. The American Association of Neuromuscular & Electrodiagnostic Medicine has also participated in the Choosing Wisely Campaign and several of their recommendations relate to what tests are unnecessary for neck and back pain.

A variety of methods may be used to diagnose axillary nerve palsy. The health practitioner may examine the shoulder for muscle atrophy of the deltoid muscle. Furthermore, a patient can also be tested for weakness when asked to raise the arm. The deltoid extension lag sign test is one way to evaluate the severity of the muscle weakness. During this test, the physician stands behind the patient and uses the patient's wrist to elevate the arm. Then, the patient is told to hold this position without the doctor's assistance. If the patient cannot hold this position on their own and an angular drop occurs, the angular lag is observed as an indicator of axillary nerve palsy. When the shoulder is at its maximum extension, only the posterior area of the deltoid muscle and the axillary nerve are working to raise the arm. Therefore, no other muscles can provide compensation, which allows the test to be an accurate measure of the axillary nerve’s dysfunction.

Additional testing includes electromyography (EMG) and nerve conduction tests. However, these should not be done right after the injury because results will be normal. These tests must be executed weeks after the initial injury and onset of symptoms. An MRI (magnetic resonance imaging) or X-Ray may also be done by a doctor.

Plexopathy symptoms often resemble spinal cord disorders. A neurosurgical consultation is usually undertaken to ensure proper diagnosis, management, and treatment. Patients with chronic symptoms will likely be advised to follow up with outpatient care from either their health care provider or specialist.

There are several tests done to diagnose hemifacial spasm. Diagnosing a case of hemifacial spasm begins with a complete neurological exam, including an Electromyography (EMG – a test that measures and records electrical activity generated in muscle at rest and in response to muscle contraction), Magnetic resonance imaging (MRI – a test that uses magnetic waves to make pictures of structures inside the head), Computed tomography (CT scan – a type of x-ray that uses a computer to make pictures of structures inside the head), and Angiography (an x-ray exam of the blood vessels when they are filled with a contrast material).

Studies have shown that the most effective method of hemifacial spasm screening is MRI. In one study only 25% of the CT scans showed the abnormality in hemifacial spasm patients, whilst more than half of the MRI imaging demonstrated a vascular anomaly. MRI imaging should be the initial screening procedure in the assessment of patients with hemifacial spasm.

The first steps in the evaluation and later management of plexopathy would consist of gathering a medical history and conducting a physical examination by a healthcare clinician. Motor function defect patterns detected within either the upper or lower extremities help with diagnosis of the disorder.

X-rays of the cervical spine, chest, and shoulder are usually ordered if symptoms point to acute Brachial plexopathy. If the physical history reveals a history of diabetes, collagen vascular disease, or symptoms of infection, the physician may order a series of blood tests including a complete blood count (CBC) and a comprehensive metabolic panel (CMP).

Surgical decompression can give excellent results if the clinical picture and the EMG suggest a compression neuropathy.

In brachial plexus neuritis, conservative management may be more appropriate.

Spontaneous recovery has been reported, but is said to be delayed and incomplete.

There is a role for physiotherapy and this should be directed specifically towards the pattern of pain and symptoms. Soft tissue massage, stretches and exercises to directly mobilise the nerve tissue may be used.⁠

The diagnosis depends on appropriate patient history backed by imaging studies like X ray and MRI. Lumbosacral spine radiographs help in the identification of the skeletal abnormality. MRI helps in confirmation.

Bernese periacetabular osteotomy resulted in major nerve deficits in the sciatic or femoral nerves in 2.1% of 1760 patients, of whom approximately half experienced complete recovery within a mean of 5.5 months.

Sciatic nerve exploration can be done by endoscopy in a minimally invasive procedure to assess lesions of the nerve. Endoscopic treatment for sciatic nerve entrapment has been investigated in deep gluteal syndrome; "Patients were treated with sciatic nerve decompression by resection of fibrovascular scar bands, piriformis tendon release, obturator internus, or quadratus femoris or by hamstring tendon scarring."

Diagnosis of a cerebrospinal fluid leak is performed through a combination of measurement of the CSF pressure and a computed tomography myelogram (CTM) scan of the spinal column for fluid leaks. The opening fluid pressure in the spinal canal is obtained by performing a lumbar puncture, also known as a spinal tap. Once the pressure is measured, a radiocontrast agent is injected into the spinal fluid. The contrast then diffuses out through the dura sac before leaking through dural holes. This allows for a CTM with fluoroscopy to locate and image any sites of dura rupture via contrast seen outside the dura sac in the imagery.

Magnetic resonance imaging is less effective than CT at directly imaging sites of CSF leak. MRI studies may show pachymeningeal enhancement (when the dura mater looks thick and inflamed), sagging of the brain, pituitary enlargement, subdural hygromas, engorgement of cerebral venous sinuses, and other abnormalities. For 20% of patients, MRIs present as completely normal. There is disagreement over whether MRI should be the study of choice. MRIs performed with the patient seated upright (vs. laying supine) are not better for diagnosing CSF leaks, but are more than twice as effective at diagnosing cerebellar tonsillar ectopia, also known as Chiari malformation. Cerebellar tonsillar ectopia shares many of the same symptoms as CSF leak, but originates either congenitally or from trauma, including whiplash strain to the dura.

An alternate method of locating the site of a CSF leak is to use heavily T2-weighted MR myelography. This has been effective in identifying the sites of a CSF leak without the need for a CT scan, lumbar puncture, and contrast and at locating fluid collections such as CSF pooling. Another highly successful method of locating a CSF leak is intrathecal contrast and MR Myelography.

Diagnosis can be made solely on the basis of history and physical examination in people who present with only facial asymmetry. For those who report neurological symptoms such as migraine or seizures, MRI scan of the brain is the imaging modality of choice. A diagnostic lumbar puncture and serum test for autoantibodies may also be indicated in people who present with a seizure disorder of recent onset.

The diagnosis may be confirmed by an EMG examination in 5 to 7 days. The evidence of denervation will be evident. If there is no nerve conduction 72 hours after the injury, then avulsion is most likely..

The most advanced diagnostic method is MR imaging of the brachial plexus using a high Tesla MRI scanner like 1.5 T or more. MR helps aid in the assessment of the injuries in specific context of site, extent and the nerve roots involved. In addition, assessment of the cervical cord and post traumatic changes in soft tissues may also be visualised.

The diagnosis is based on symptoms and signs alone and objective testing is expected to be normal. This syndrome may be clinically tested by flexing the patients long finger while the patient extends the wrist and fingers. Pain is a positive finding.

The chief complaint of this disease is usually pain in the dorsal aspect of the upper forearm, and any weakness described is secondary to the pain. Tenderness to palpation occurs over the area of the radial neck. Also, the disease can be diagnosed by a positive "middle finger test", where resisted middle finger extension produces pain. Radiographic evaluation of the elbow should be performed to rule out other diagnoses.

A computed tomography (CT) scan is another examination method often used for the diagnosis of Tarlov cyst. Unenhanced CT scans may show sacral erosion, asymmetric epidural fat distribution, and cystic masses that are have the same density with CSF. CT Myelogram is minimally invasive, and could be employed when MRI cannot be performed on patient.

Two most commonly used and effective examination method for Tarlov Cysts are MRI and CT. Both CT and MRI are good imaging procedures that allow the detection of extradural spinal masses such as Tarlov cysts. Magnetic resonance neurography is an emerging imaging technology based on MRI that highlights neurologic tissue. Often cysts are under reported and under diagnosed as radiologists and neurosurgeons have been traditionally taught to ignore these cysts. Patients frequently experience difficulty in diagnosis, however this is changing as Tarlov cysts have now been recognized by NORD as a rare disease.

Microvascular decompression appears to be the most popular surgical treatment at present. Microvascular decompression relieves pressure on the facial nerve, which is the cause of most hemifacial spasm cases. Excellent to good results are reported in 80% or more cases with a 10% recurrence rate. In the present series approximately 10% had previously failed surgery. Serious complications can follow microsurgical decompressive operations, even when performed by experienced surgeons. These include cerebellar haematoma or swelling, brain stem infarction (blood vessel of the brain stem blocked), cerebral infarction (ischemic stroke resulting from a disturbance in the blood vessels supplying blood to the brain), subdural haematoma and intracerebral infarction (blockage of blood flow to the brain). Death or permanent disability (hearing loss) can occur in 2% of patients of hemifacial spasm.

While conservative approaches for rehabilitation are ideal, some patients will not improve and surgery is still an option. Patients with large cervical disk bulges may be recommended for surgery, however most often conservative management will help the herniation regress naturally. Procedures such as foraminotomy, laminotomy, or discectomy may be considered by neurosurgeons and orthopedic surgeons.

Signals from the sciatic nerve and it branches can be blocked, in order to interrupted transmission of pain signal from the innervation area, by performing a regional nerve blockade called a sciatic nerve block.

Genetic counseling is often recommended to provide more information about fetal CPCs, to answer questions and concerns, and to outline available options such as amniocentesis or a blood test from the mother. There is a possible association between ultrasound-detected fetal CPCs and Trisomy 18. It is not correlated to the presence of Trisomy 21 (Down syndrome).

Generally the risks are very low if there are no other risk factors. If no additional abnormalities are detected by a thorough "level II" ultrasound, the likelihood the fetus has trisomy 18 is very low.

A meta-analysis of 8 studies between 1990 and 2000 with choroid plexus cysts that were identified in second-trimester (an incidence of 1.2%). The incidence of the cysts in women younger than 35 was 1% (n=1017). The study found no cases of trisomy 18 in fetuses with cysts whose mother was younger than 35. The study concluded that "there is no evidence that detection of isolated choroid plexus cyst in women who are <35 years of age increases the risk of trisomy 18".

Other factors which may have a bearing on the baby's chances of developing chromosome problems include:

- mother's age at the expected date of delivery

- the results of serum screening; XAFP triple testing or quad screening

- evidence of other "fetal findings" seen at the time of the ultrasound that may suggest a chromosome problem

Criteria for CSF abnormalities:

- Increased opening pressure (> 200mm of H2O)

- Increased Leukocytes (>4/mm3)

- Elevated protein (>50 mg/dL)

- Decreased glucose (<60 mg/dL)

Tumor Markers:

- Carcinoembryonic antigin (CEA)

- alpha-fetoprotein

- beta-human chorionic gonadotropin

- carbohydrate antigen19-9

- creatine-kinase BB

- isoenzyme

- tissue polypeptide antigen

- beta2-microglobulin,

- beta-glucoronidase

- lactate dehydrogenase isoenzyme-5

- vascular endothelial growth factor

These markers can be good indirect indicator of NM but most are not sensitive enough to improve cytogical diagnosis.

Avoiding false-negative

- Draw CSF from symptomatic or radiographically demonstrated disease.

- Draw large amount of CSF (>10.5mL).

- Don't delay processing of specimen.

- Obtain at least 2 samples. The first sample has diagnostic sensitivity of 54% but with repeated sampling, diagnostic sensitivity is increased to 91%.

Ideal procedure for diagnosis:

Lumbar puntures --> cranial MRI --> spinal MRI --> radioisotope CSF flow --> ventricular or lateral cervical spine CSF analysis (if previous step yields no definitive answer)

The distinct innervation of the hand usually enables diagnosis of an ulnar nerve impingement by symptoms alone. Ulnar nerve damage that causes paralysis to these muscles will result in a characteristic ulnar claw position of the hand at rest. Clinical tests such as the card test for Froment's sign, can be easily performed for assessment of ulnar nerve. However, a complete diagnosis should identify the source of the impingement, and radiographic imaging may be necessary to determine or rule-out an underlying cause.

Imaging studies, such as ultrasound or MRI, may reveal anatomic abnormalities or masses responsible for the impingement. Additionally, imaging may show secondary signs of nerve damage that further confirm the diagnosis of impingement. Signs of nerve damage include flattening of the nerve, swelling of the nerve proximal to site of injury, abnormal appearance of nerve, or characteristic changes to the muscles innervated by the nerve.

The diagnosis of NM is based on the detection of malignant cells in the CSF, the demonstration of leptomeningeal tumor cell deposits on neuroimaging, or both. CSF examination is the most useful diagnostic tool for NM. Patients with suspected NM should undergo one or two lumbar punctures, cranial magnetic resonance imaging (MRI), spinal MRI, and a radioisotope CSF flow study to rule out sites of CSF block. If the cytology remains negative and radiological studies are not definitive, consideration may be given to ventricular or lateral cervical spine CSF analysis based on the suspected site of predominant disease. Consideration of signs, symptoms, and neuroimaging can help with the placement to where CSF is drawn. Median time of diagnosis from initial primary cancer diagnosis is between 76 days and 17 months. NM diagnosis has been increasing and will continue to increase due to better primary care and longer survival time of cancer patients.

Difficulties in Diagonsis:

NM is multifocal and CSF at a particular site may show no abnormalities if the pathological site is far away. Only 50% of those suspected with NM are actually diagnosed with NM and only the presence of malignant cells in the CSF is diagnosis conclusive.

Techniques:

- MRI: Meningeal findings are described with the following characteristics: Nodular meningeal tumor, meningeal thickening >3 mm and a subjectively strong contrast enhancement. A smooth contrast enhancement of the meninges was judged to be typical for inflammatory, nonneoplastic meningitis.

- CSF cytology: is performed after drawing the CSF by lumbar puncture.

- Cytogenetic: measures chromosomal content of cells and fluorescence in situ hybridization which detects numerical and structural genetic aberrations as a sign of malignancy. This is especially useful for liquid tumors such as leukemia and lymphoma. Some of the techniques that achieve this are flow cytometry and DNA single-cell cytometry. However, cytogenetic only assist in diagnosis and is less preferred.

- Meningeal Biopsy: may be performed when all of the above criteria is inconclusive. Biopsy is only effective when performed at the region where there's enhancement on the MRI.