• Indications for the Neurometer® CPT sNCT™ Evaluation
• Professional Responsibilities
• Inappropriate Use of the sNCT™ Evaluation
• General Utilization Guidelines
  • Distal Symmetrical Polyneuropathy
  • Asymmetric Polyneuropathy
  • Radiculopathy
  • Compressive and Focal Nerve Lesions
• Specialty Utilization Guidelines
  • Pain Management
  • Endocrinology
  • Nephrology
  • Neurology
  • Physical Medicine and Rehabilitation
  • Neurosurgery
  • Oncology
  • Orthopedic Surgery
  • Podiatry
  • Rhumatology
  • Urology
  • Family Practice/Internal Medicine
  • Chiropractic
  • Physical/Occupational Therapy
• Supplemental Information

Indications for the Neurometer® CPT sNCT™ Evaluation

        The automated, neuroselective sNCT™ evaluation is indicated for any patient with a presumptive diagnosis of sensory nerve dysfunction that requires an objective quantitative assessment. Peripheral sensory nerve impairments may be divided into four major categories: polyneuropathy, radiculopathy, compressive neuropathy and focal nerve lesions. Additional valuable diagnostic information may be obtained to assist in differentiating axonal from demyelinating types of neuropathology. The sNCT evaluation procedure identifies and localizes areas of abnormal function, determines the severity of the abnormality and aids in the diagnosis by guiding and evaluating treatment.

Professional Responsibilities

        The clinical judgement of a licensed doctor is required and appropriate to determine if a patient's symptoms and physical examination merit an sNCT evaluation. The doctor must prescribe the evaluation including the body sites to be tested according to his/her differential diagnosis. Trained (non physician) personnel may perform the test procedure. A clinician's impression should accompany the software generated analysis of the sNCT test results. The neurophysiologic data from the tests should be maintained in the patient's medical record.
        The manufacturer's recommended procedural guidelines must be followed to allow reproducible automated sNCT generated CPT values to be obtained in a standardized double blind fashion with a resolution of +/- 20 æAmperes (p<0.006) and to permit the detection of patient non-compliance.
        The clinician must document why the sNCT evaluation is indicated, the interpretation of the sNCT test results and how the sNCT findings will affect the patient's management. Reasons for a repeat study, including a comparison with the previous test results, must also be documented.
        This examination is a prescription procedure that may only be preformed by or on the order of a licensed healthcare professional. The sNCT evaluation provides the clinician with a means to obtain an objective quantitative differential diagnosis of sensory nerve impairments and to assess and document the efficacy of therapeutic intervention.

Inappropriate Use of the sNCT™ Evaluation

Inappropriate use of the sNCT™ evaluation includes:

1. Indiscriminate testing of patients without a complete physical examination and documentation of sensory abnormalities.
2. Testing patients without documented suspected sensory impairments.
3. Testing patients without establishing and documenting why the test is indicated.
4. Testing an excessive number of sites beyond those necessary to determine a differential diagnosis including, with rare exceptions, testing for both an upper and a lower extremity radiculopathy at the same time on the same patient.
5. Conducting the sNCT evaluation and not incorporating the test result findings into the patient's management.
6. Repeat testing of patients without an examination and documentation of a change in sensory abnormalities or an equivocal response to a therapeutic intervention.
7. Testing which is not reasonable or necessary to diagnose or treat an illness or injury or evaluate to a clinically equivalent response to a therapeutic intervention.
8. Testing conducted as a screening procedure during the routine physical examination of a healthy patient.

General Utilization Guidelines

Distal Symmetrical Polyneuropathy
        Sensory Nerve Conduction Threshold (sNCT™) evaluations are conducted at symptomatic and asymptomatic sites to document abnormal distributions of sensory nerve function and assist in the diagnosis. Diagnoses commonly include the following categories: radiculopathy, compressive/focal lesions and polyneuropathy. Standardized test sites and protocols provide a documented basis consistent with a clinical diagnosis.
        sNCT evaluations from the tips of the ring fingers may be indicated when abnormal measures are obtained from the tests on the great toes to determine the presence of polyneuropathy in the upper extremity. If sNCT findings from these sites are normal, then no further testing is required. If sNCT findings are uniformly anesthetic at a site, then more proximal testing on a site where sNCT measures are obtainable is appropriate. When proximal testing is conducted on the same nerve additional billing is inappropriate.
(Note:  Proximal testing determines the extent of the neuropathy, aids in performing a differential diagnosis and enables the physician to quantify changes in the patient's condition in a follow-up evaluation.)

Asymmetric Polyneuropathy
        Asymmetric polyneuropathy is diagnosed through bilateral, proximal and distal sNCT evaluations. Sites evaluated include the peroneal nerve (distal limb nerve), lateral antebrachial cutaneous (mid-limb nerve) and C2 dermatome (proximal segment nerve).
(Note:  Asymmetric polyneuropathies are primarily immune mediated and associated with conditions such as Chronic Inflammatory Demyelinating Polyneuropathy (CIDP).)

Radiculopathy
        Radiculopathic sensory impairments are evaluated by testing two different nerves within the same dermatome or testing the same nerve in two different dermatomes. Unless a distal polyneuropathy is suspected, proximal testing within the same dermatome distribution is unnecessary. When proximal testing conducted on the same nerve additional billing is inappropriate.
        Upper extremity cervical radiculopathy is diagnosed through bilateral sNCT evaluations at sites including the following distal finger/dermatome test sites: thumb (C6), index finger (C7), and the little finger (C8). Lower extremity lumbar/sacral radiculopathy is diagnosed through bilateral sNCT evaluations at sites including the following distal toe/dermatome test sites: medial great toe (L4), dorsal middle toe (L5) and lateral little toe (S1).
(Note:  On rare occasions, radiculopathies may involve upper cervical (neck, cervical) dermatomes or thoracic (mid-back) dermatomes. sNCT evaluation of these types of radiculopathies typically include bilateral testing of two adjacent dermatome test sites.)

Compressive and Focal Nerve Lesions
        Focal nerve lesions, such as those induced by a traumatic injury, are evaluated and confirmed by determining a normal sensory function proximal to the suspected lesion and abnormal function distally. For example, evaluation of carpal tunnel syndrome is performed by testing the median nerve proximal and distal to the carpal tunnel - at the palmar cutaneous branch of the median nerve and the distal digital branches of the median nerve, respectively. Upon obtaining measures consistent with the suspected condition, the distal digital branches of the ulnar nerve at the little finger are evaluated to rule out a distal polyneuropathy mimicking or co-existing with carpal tunnel syndrome.
(Note:  The sNCT evaluation can be performed immediately following an acute nerve injury. A delay in performing the sNCT evaluation may result in a lost opportunity for a therapeutic intervention.)

Specialty Utilization Guidelines

Pain Management
        Patients being treated for chronic pain are administered sNCT evaluations when neurologic sensory signs or symptoms require an objective quantitative evaluation for a diagnosis or assessment. Conditions can include spinal cord injuries, polyneuropathies, radiculopathies, focal or compressive nerve lesions.
        The differential diagnosis of a sensory impairment from another etiology such as soft tissue injury, sprain or strain injury, vascular insufficiency, somatic referred pain, or psychogenic origin must be considered when sNCT test results are within normal limits. sNCT test results within normal limits do not preclude the necessity for medical care, but merely establish a basis for the differential diagnosis and treatment plan.

Endocrinology
        Endocrinologists use the sNCT examination procedure to evaluate metabolic polyneuropathies commonly observed in clinical endocrinology. Annual sNCT evaluations for patients at risk for polyneuropathy (e.g. diabetes, hypothyroidism) are recommended to objectively assess the presence or absence of a polyneuropathy or evaluate its progression. Particular concern is given to evaluating protective sensation. Normal sNCT evaluation results indicate that no further sNCT testing beyond the annual exam is necessary unless a change in the clinical condition suggesting sensory dysfunction warrants a repeat evaluation.
        Patients with certain types of endocrine disorders (e.g. diabetes) are susceptible to developing compressive neuropathies and radiculopathies and testing for these conditions may be required based upon the clinical impression that the differential diagnosis of a patient's sensory impairment includes these conditions.

Nephrology
        Nephrologists use the sNCT procedure to evaluate patients with kidney disease to assist in determining when to commence dialysis therapy. The evaluation is prescribed when clinical examination findings suggest development of an impairment in distal sensory function and an objective evaluation is required to confirm the diagnosis of polyneuropathy.
        Typically, the distal great toe test site is tested bilaterally and if a polyneuropathy is detected then dialysis therapy may be considered to reverse the condition and prevent its progression. Normal sNCT evaluation results indicate that no further sNCT testing beyond the annual exam is necessary unless a change in the clinical condition suggesting sensory dysfunction warrants a repeat evaluation.
        Nephrologists also prescribe the sNCT evaluation to be administered to end stage renal disease patients to provide an index of the long-term adequacy of dialysis therapy. Additionally, the sNCT evaluation may be prescribed to be administered to the fingers of end stage renal disease patients to screen for the development of Carpal Tunnel Syndrome (CTS). Specifically, the bilateral distal phalanges of the index finger and little finger are routinely tested on a quarterly basis for this purpose. Fifty percent of patients receiving dialysis for three years or more develop CTS without experiencing the normal painful symptoms due to concurrent upper extremity polyneuropathy. Left untreated, patients may suffer up to an 80% loss of function in the affected hand.

Neurology
        Neurologists use the sNCT examination procedure to objectively evaluate sensory dysfunction associated with a variety of conditions, such as symmetric or asymmetric inherited and acquired sensory polyneuropathies, and to distinguish whether they are myelinopathies or axonopathies. sNCT evaluations are used to objectively evaluate a suspected sensory impairment and assess disease progression and the efficacy of therapeutic intervention. Follow-up evaluations are generally only required when: 1) There is a clinical question as to whether the patients sensory pathology is deteriorating or 2) There is a clinical question as to whether the patients sensory impairment is responding to therapeutic intervention after six weeks of therapy.
        The sNCT examination procedure may be prescribed for neuroselective assessment and monitoring of CNS sensory function following cerebral vascular events and other types of CNS pathology (e.g. multiple sclerosis or spinal cord pathology that effects cutaneous sensory function). The sNCT evaluation is usually prescribed for the extremities - the affected extremity and a matched control extremity. The electrodiagnostic evaluation does not have to be repeated unless there is a clinical suspicion of a deterioration of the patient's sensory complaints which requires an objective quantitative neuroselective evaluation.
        The sNCT examination procedure may also be used to confirm or evaluate a suspected radiculopathy or focal nerve lesion, such as a carpal tunnel syndrome and to determine the most appropriate therapeutic intervention. Normal sNCT evaluation results indicate that no further sNCT testing is necessary unless a change in the clinical condition suggesting sensory dysfunction warrants a repeat evaluation.

Physical Medicine and Rehabilitation
        Physiatrists use the sNCT evaluation procedure to evaluate suspected sensory impairments based on clinical examination and determine the most appropriate therapeutic intervention. An initial sNCT evaluation of the patient is generally all that is required unless there is a suspected deterioration of the patient's sensory impairment based on clinical examination findings.
        The sNCT examination may be used with rehabilitation patients to quantify the severity of sensory impairment(s) secondary to brain or spinal cord injuries. Generally, only the affected extremity and a control site need to be tested. The physiatrist may use the sNCT evaluation to confirm or evaluate a suspected radiculopathy or focal nerve peripheral nerve lesions to determine the most appropriate therapeutic intervention. Amputees may require testing of their stump prior to fitting a prosthesis in order to objectively assess protective sensation.

Neurosurgery
        Neurosurgeons use the sNCT evaluation procedure to monitor return of sensation after a nerve repair. The sNCT evaluation is conducted at the skin or mucosal site innervated by a repaired or transplanted nerve at three month intervals following surgery. Once sNCT measures are obtainable from the site, thereby indicating successful repair, no further testing is required. If by the ninth month no measures are obtainable, then this may indicate formation of a neuroma or that the surgery was unsuccessful and that the nerve function is not recovering.

Oncology
        Oncologists use the sNCT evaluation procedure to assess the polyneuropathy of cancer and the neurotoxic side-effects of chemotherapeutic agents in order to assist in developing and modifying treatment plans/goals. The sNCT procedure is indicated prior to treating a cancer patient using chemotherapy with known neurotoxic side effects, to establish a baseline of sensory function. Bilateral testing is generally conducted at the great toe test site and a cephalic test site. Testing is conducted on a bi-weekly basis unless there is a clinical manifestation of an acute sensory impairment which requires an immediate evaluation.

Orthopedic Surgery
        Orthopedic surgeons use the sNCT evaluation to assess sensory nerve functional integrity associated with injuries resulting in sensory dysfunction (e.g. radiculopathies and focal/compressive nerve injuries). The sNCT evaluation is conducted to determine the severity of clinically detected sensory impairments and assist in decisions regarding surgical intervention. Follow-up sNCT evaluations are only necessary if new sensory impairments develop which require an objective quantitative neuroselective evaluation.

Podiatry
        Podiatrists use the sNCT evaluation to assist in the differential diagnosis and quantitative evaluation of conditions resulting in sensory dysfunction in the foot such as polyneuropathy, radiculopathy, neuroma, focal nerve lesion and tarsal tunnel syndrome. Generally, two to three nerves are tested bilaterally to perform the electrodiagnostic evaluation of the foot. Once the podiatrist has treated the neuropathologic condition causing sensory dysfunction in the foot and the symptoms are resolved, no further sNCT evaluations are required for that condition. Podiatrists don't generally treat polyneuropathy or radiculopathy, so additional testing of the foot for these conditions would not be necessary and the patient would instead be referred to the appropriate healthcare provider.

Rhumatology
        Rheumatologists use the sNCT evaluation procedure to assess sensory impairments secondary to immunological etiology, in contrast to other types of apparent clinical neuropathy (e.g. CTS, polyneuropathy). Rheumatologists treat apparent sensory dysfunction (e.g. pain limited loss of motion with arthritis) but do not treat focal or metabolic neuropathies.

Urology
        Urologists use the sNCT evaluation procedure to assist in the differential diagnosis of neurogenic verses psychogenic or other impotence. Typically, the ring finger is tested bilaterally and the penis is tested at one or two sites - the glans and the proximal dorsal shaft. Normal sNCT evaluation results indicate that no further sNCT testing is necessary unless a change in the clinical condition suggesting sensory dysfunction warrants a repeat evaluation.

Family Practice/Internal Medicine
        The primary care provider uses the sNCT evaluation procedure to assist in the differential diagnosis of polyneuropathy, compressive/focal neuropathy and radiculopathy. The procedure is only administered when clinical findings suggest a sensory impairment requiring an objective quantitative assessment for verification purposes. Typically, the test is only conducted once on a patient unless there is the development of new impaired sensory symptoms which warrant a new evaluation.
        Annual sNCT evaluations for patients at risk for polyneuropathy (e.g., diabetes, hypothyroidism) are recommended to objectively assess the presence or absence of a polyneuropathy. Once sensory abnormalities are detected, annual follow-up examinations may be indicated to quantify the progression of the polyneuropathy.

Chiropractic
        Chiropractors use sNCT evaluation to assist in the differential diagnosis and quantitative evaluation of conditions resulting in sensory dysfunction. Chiropractic patients may be administered the sNCT evaluation when sensory neurologic signs or symptoms are detected which require an objective quantitative evaluation for differential diagnostic and or assessment purposes. Results of the sNCT evaluation by be used to assist in establishing a treatment protocol or if a referral is indicated. The absence of abnormal measures indicates that no further testing is needed.
        The sNCT evaluation may be repeated to establish the outcome of therapeutic intervention and to determine maximum medical improvement. If a clinical evaluation is equivocal in determining the efficacy of therapeutic intervention with respect to the sensory symptomatology, a repeat examination may be conducted following four to six weeks of therapy. An extenuating circumstance, such as an exacerbation of an existing condition or the development of new sensory neurological impairments, may warrant a repeat sNCT evaluation.

Physical/Occupational Therapy
        The sNCT evaluation provides the physical and occupational therapist with an objective, quantitative means to assess and document the efficacy of therapeutic intervention.

Supplemental Information

        The automated sensory Nerve Conduction Threshold (sNCT™) electrodiagnostic evaluation generates neuroselective Current Perception Threshold (CPT) measures. This functional electrodiagnostic procedure is employed to diagnose pathology of the peripheral nerve, spinal cord or brain. The test can be conducted at any cutaneous or mucosal body site to determine the conduction thresholds from the large and small myelinated fibers and the unmyelinated sensory nerve fibers with a resolution of +/- 20 µAmperes (p<0.006). Pathological findings include abnormally low sensory thresholds reflecting hyperesthetic conditions, abnormally elevated sensory thresholds reflecting a hypoesthetic conditions and unobtainable sensory thresholds representing anesthetic conditions. Threshold measures are evaluated by comparing them to clinically established normative values. Automated sNCT testing permits the distribution of sensory impairments to be mapped out and identification of the specific type(s) of nerve fibers, i.e. myelinated or unmyelinated, to which the pathology is confined.

Modified 07/20/04.
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