For any item to be covered by Medicare, it must 1) be eligible for a defined
Medicare benefit category, 2) be reasonable and necessary for the diagnosis or
treatment of illness or injury or to improve the functioning of a malformed
body member, and 3) meet all other applicable Medicare statutory and
regulatory requirements.

The purpose of a Local Coverage Determination (LCD) is to provide information
regarding "reasonable and necessary" criteria based on Social Security Act 
1862(a)(1)(A) provisions.

In addition to the "reasonable and necessary" criteria contained in this LCD
there are other payment rules, which are discussed in the following documents,
that must also be met prior to Medicare reimbursement:

  * The LCD-related Standard Documentation Requirements Article, located at the bottom of this policy under the Related Local Coverage Documents section.
  * The LCD-related Policy Article, located at the bottom of this policy under the Related Local Coverage Documents section.
  * Refer to the Supplier Manual for additional information on documentation requirements.
  * Refer to the DME MAC web sites for additional bulletin articles and other publications related to this LCD.

For the items addressed in this LCD, the "reasonable and necessary" criteria,
based on Social Security Act 1862(a)(1)(A) provisions, are defined by the
following coverage indications, limitations and/or medical necessity.

An external upper limb tremor stimulator of the peripheral nerves of the wrist
(K1018) and related supplies and accessories (K1019) will be denied as not
reasonable and necessary.

GENERAL

A Standard Written Order (SWO) must be communicated to the supplier before a
claim is submitted. If the supplier bills for an item addressed in this policy
without first receiving a completed SWO, the claim shall be denied as not
reasonable and necessary.

For Durable Medical Equipment, Prosthetics, Orthotics and Supplies (DMEPOS)
base items that require a Written Order Prior to Delivery (WOPD), the supplier
must have received a signed SWO before the DMEPOS item is delivered to a
beneficiary. If a supplier delivers a DMEPOS item without first receiving a
WOPD, the claim shall be denied as not reasonable and necessary. Refer to the
LCD-related Policy Article, located at the bottom of this policy under the
Related Local Coverage Documents section.

For DMEPOS base items that require a WOPD, and also require separately billed
associated options, accessories, and/or supplies, the supplier must have
received a WOPD which lists the base item and which may list all the
associated options, accessories, and/or supplies that are separately billed
prior to the delivery of the items. In this scenario, if the supplier
separately bills for associated options, accessories, and/or supplies without
first receiving a completed and signed WOPD of the base item prior to
delivery, the claim(s) shall be denied as not reasonable and necessary.

An item/service is correctly coded when it meets all the coding guidelines
listed in CMS HCPCS guidelines, LCDs, LCD-related Policy Articles, or DME MAC
articles. Claims that do not meet coding guidelines shall be denied as not
reasonable and necessary/incorrectly coded.

Proof of delivery (POD) is a Supplier Standard and DMEPOS suppliers are
required to maintain POD documentation in their files. Proof of delivery
documentation must be made available to the Medicare contractor upon request.
All services that do not have appropriate proof of delivery from the supplier
shall be denied as not reasonable and necessary.

**Background**

A task force of the International Parkinson and Movement Disorder Society has
defined tremors as an involuntary, rhythmic, oscillatory movement of a body
part.1 The task force also proposed a definition for essential tremor (ET) as
a tremor syndrome of at least 3 years duration, excluding isolated head or
isolated voice tremors, in the absence of inherited dystonia, ataxia, or
parkinsonism.1 Based on a 2014 epidemiological study, the estimated number of
ET cases in the United States was 7 million (6.38 to 7.63 million),
corresponding to approximately 2.2% of the population, making it one of the
most common movement disorders.2 The prevalence of ET increases with age, with
reported rates of 4% or higher in people over the age of 60 years.3 An
exponential increase is seen with advancing age, with rates reaching in excess
of 20% in those 95 years and older.3 The aim of this summary of evidence was
to determine if external upper limb tremor stimulator therapy, also known as
transcutaneous afferent patterned stimulation (TAPS) therapy, reduces ET
symptoms immediately and 60-minutes after a therapy session, and if tremor
stimulation therapy reduces ET symptoms in the longer term ( 3 months).

**Food and Drug Administration (FDA) Approval**

Cala Trio (External upper limb tremor stimulator):

<https://www.accessdata.fda.gov/cdrh_docs/pdf17/DEN170028.pdf>

<https://www.accessdata.fda.gov/cdrh_docs/pdf20/K203288.pdf>

**Literature Analysis**

A randomized, double-blinded, sham-controlled pilot trial, by Lin, et al.,4
compared the efficacy of either median and radial nerve stimulation with a
non-invasive, wrist-worn, peripheral nerve stimulation device (n = 10), or a
sham device (n = 13) for the symptomatic relief of hand tremors in
participants with ET. Efficacy was measured using a change in the Tremor
Research Group's Essential Tremor Rating Assessment Scale (TETRAS) Archimedes
spiral drawing task post-stimulation compared with pre-stimulation, after a
single treatment session. In the treatment group, blinded rater scores
significantly improved post-stimulation (1.77 + 0.21) compared to pre-
stimulation (2.77 + 0.22; p = 0.01). In the sham group, scores did not change
significantly following stimulation (2.37 + 0.22) compared to pre-stimulation
(2.62 + 0.14; p = 0.37). The response to treatment corresponded to an
estimated hand tremor amplitude reduction of 60% + 8.4% and was significantly
greater in the treatment than in the sham group (p = 0.02). Limitations of the
study included the small cohort, short duration, limited details on the study
methodology, and possible confounding of results due to pharmacologic
treatments in use.

A multi-center double-blinded, randomized, sham-controlled trial, by Pahwa, et
al.,5 evaluated the safety and effectiveness of a wrist-worn peripheral nerve
stimulation device in 77 patients with ET (treatment n = 40, sham n = 37). The
primary outcome of the study was improvement in tremor severity in the hand as
measured by the TETRAS task 6 Archimedes spiral score following stimulation
compared to sham stimulation based on a single in office session. The study
failed to reach its primary endpoint; there was not a significantly larger
improvement in the Archimedes spiral rating with stimulation treatment
compared to sham (p = 0.26). There were statistically significant improvements
in some secondary endpoints compared to sham including the individual forward
postural hold upper limb tremor task (TETRAS task 4) sub-score (p = 0.004),
the combined upper limb tremor task (TETRAS task 4) score (p = 0.017), and the
total TETRAS performance score (p = 0.015). Subject-rated improvements in
activities of daily living (ADL) were significantly greater in 4 out of 7 ADL
tasks in the treatment group compared with sham. A greater percentage of ET
patients (88%) reported improvement in the stimulation group as compared to
the sham group (62%) (p = 0.019) based on the clinical global impression-
improvement (CGI-I) ratings. The study limitations included the small sample
size, single treatment session, and sham device effects, which were not
subtracted from the active scores.

The objective of a single-session, open-label study, by Yu, et al.,6 was to
determine the time profile of therapeutic benefit from TAPS therapy for up to
60 minutes following a stimulation session in 15 patients (mean age 72.2 
8.6) with ET. Four hand tremor-specific tasks (postural hold, spiral drawing,
finger-to-nose reach, and pouring) from the Fahn-Tolosa-Marin Clinical Rating
Scale (FTM-CRS) were performed and assessed prior to, during, and 0-, 30- and
60-minutes following TAPS therapy. Mean FTM-CRS rating improved with TAPS
therapy, with the peak tremor reduction occurring 30 minutes following the end
of stimulation. Twelve of 15 patients had improvement in mean clinical rating
at least 60 minutes following the end of stimulation (p = 4.6e-9).
Accelerometer-measured tremor power improved with TAPS therapy across all
tasks; the postural hold task had the greatest reduction in tremor power, with
a median peak 5.9-fold improvement (83% reduction) in tremor power occurring
30 minutes following the end of stimulation. Median peak improvements for the
other tasks were 2.4-fold (57% reduction) for spiral drawing, 1.6-fold (38%
reduction) for finger-to-nose reach, and 2.5-fold (59% reduction) for pouring.
Eleven (11) of 15 patients had at least 60 minutes of benefit for postural
hold, spiral drawing, and finger-to-nose reach tasks (p = 9.8e-8), while 10 of
14 patients had at least 60 minutes of benefit for the pouring task (p =
5.8e-7). Limitations of this study include the small sample size, the open-
label design, the short duration of follow-up (single-session), heterogenity
in baseline ET severity, and 5 of 15 participants remained on their standard-
of-care ET medication during the study, which may have confounded the results.

A prospective, multi-center, single-arm, open-label clinical trial, by
Isaacson, et al.,7 evaluated the safety and efficacy of TAPS therapy in 205
patients over a 3-month period using a wrist-worn neuromodulation device. The
study included 3 in-clinic visits consisting of a screening and enrollment
visit, and a 1- and 3-month follow-up visit. Between visits, patients were
instructed to use the device 2x/day for 40 minutes. The clinician rated TETRAS
dominant hand score and patient-rated Bain & Findley Activities of Daily
Living (BF-ADL) were the co-primary efficacy endpoints, while improvement in
tremor power between the pre- and post-stimulation postural holds (measured by
accelerometer) was the secondary efficacy endpoint. On average, patients
completed at least one stimulation session per day for 78% of the days they
were enrolled in the study and completed 68% of their total instructed
stimulation sessions. The TETRAS dominant hand scores improved from baseline
to the third study visit from a mean (standard deviation (SD)) of 12.6 (2.7)
to 9.8 (3.5) (mean difference -2.8 (2.8), p < 0.0001). There was also a
statistically significant improvement in the combined BF-ADL dominant hand
score from a baseline mean (SD) of 18.4 (3.8) to 13.4 (4.4) (mean difference
-5.0 (4.3), p < 0.0001). Accelerometer recordings before and after 21,806
treatment sessions showed that 92% of patients experienced improvement in
tremor power, with 54% of patients experiencing 50% improvement; mean tremor
power decreased from 1.1  0.3 (m/s2)2 pre-stimulation to 0.3  0.1 (m/s2)2
post-stimulation (p < 0.0001). No device-related serious adverse events (AEs)
were reported, and 18% of patients experienced non-serious device-related AEs.
Limitations of the study included its open-label, single-arm design, high
drop-out rate, lack of sham control, and unblinded clinical raters. Although
the data did produce statistically significant results, the authors noted a
large variability in the magnitude of effect on different tasks.

A retrospective, post-market surveillance study, by Brillman, et al.,8 aimed
to evaluate real-world usage and effectiveness of TAPS delivered by a non-
invasive, wrist-worn, neuromodulation device in 321 patients (mean age 71
years) for the management of hand tremors associated with ET. Effectiveness
was assessed by measurement of tremor power (i.e., frequency and amplitude of
tremor motion to characterize tremor severity), via device-prompted postural
hold tremor accelerometry measurements, immediately before and after a session
of stimulation. Habituation of therapy was assessed in patients using the
device for at least 1 year by evaluating effectiveness of therapy in their
first 90 days of use compared to effectiveness after 90 days of use. Usage was
defined as the average number of sessions, of at least 20 minutes duration,
per week, and was gathered from data collected from integrated device logs. A
total of 216 participants provided data that met effectiveness analysis
criteria; immediately after TAPS therapy, 93% of patients had some reduction
in tremor severity, with 59% of patients experiencing at least 50% reduction.
Patients with the most severe pre-therapy tremors experienced the greatest
reduction of tremor severity after stimulation (89% reduction). For patients
who used TAPS therapy for greater than 1 year (n = 89), there was no
significant habituation to therapy noted. Usage analysis identified total
usage periods ranging from 90 to 633 days, with patients using the device 5.4
times per week, on average. Of the 69 participants (representing 21.5% of
total patients) who returned a voluntary survey, 84% reported improvement in
at least one key activity (i.e., eating, drinking, or writing), 65% reported
improvement in overall quality of life, and 65% indicated a preference for
TAPS therapy over both medication and surgical intervention for tremor
management. The investigators recommended additional studies to better define
TAPS dosing (i.e., number of sessions per week) and delivery. The study was
limited by the retrospective design, lack of control for confounding, and the
amount of missing or excluded data. Additionally, because postural hold data
was only obtained immediately after a stimulation session, the duration of
treatment effect is not known.

**Evidence Based Guidelines**

The American Academy of Neurology (AAN) first developed an evidenced based
guideline for the treatment of Essential Tremor in 2005, which was updated in
2011 and reaffirmed in 2022. These guidelines do not offer a recommendation
for or against the use of the Cala Trio.9

##

**Professional Society Recommendations**

No relevant Professional Society Recommendations were identified

**Other**

**International Essential Tremor Foundation (IETF) - Essential Tremor in Adult
Patients**10

**Summary of Consensus Guide (in relevant part):**

_**Figure 1. Overview of Management of Essential Tremor**_

_**Step 1** \- Examination to establish presence of tremor _

_**Step 2** - Rule out other causes of tremor, such as medications,
Parkinson's disease, dystonia, etc. _

_**Step 3** \- First-line pharmacological approaches: propranolol, primidone,
or a combination. Optional add-ons: Cala Trio and/or other non-invasive
devices _

_**Step 4** - Cala Trio and/or other non-invasive devices (if not added during
Step 3). Second-line and third-line pharmacological approaches: topiramate,
gabapentin, other beta blockers, or benzodiazepines_

_**Step 5** - DBS [Deep Brain Stimulation], FUS [Focused Ultrasound], or other
surgical approaches _

_At any time during steps 3-5:_

  *     *       * _Assistive devices can be used_
      * _Discussions with patients regarding social stigmas, and for severe cases, social security/disability support_

The aim of this summary of evidence was to determine if external upper limb
tremor stimulator therapy, also known as TAPS therapy, reduces ET symptoms
immediately and 60-minutes after a therapy session, and if tremor stimulation
therapy reduces ET symptoms in the longer term ( 3 months). Studies that were
reviewed were analyzed for risk of bias (ROB). For randomized control trials
(RCTs), ROB was assessed using the Cochrane Collaboration's tool for assessing
risk of bias.11 To evaluate the ROB in non-randomized studies, the ROB in Non-
Randomized Studies of Interventions (ROBINS-I) tool was used.12 The Grading of
Recommendations, Assessment, Development, and Evaluation (GRADE) approach was
used as a method of grading the certainty of evidence, which can range from
high to very low, and is defined as follows:13

High | Further research is very unlikely to change our confidence in the
estimate of effect  
---|---  
Moderate | Further research is likely to have an important impact on our
confidence in the estimate of effect and may change the estimate  
Low | Further research is very likely to have an important impact on our
confidence in the estimate of effect and is likely to change the estimate  
Very Low | Any estimate of effect is very uncertain  
  


**Certainty of Evidence  
** **Outcomes:**

Symptom reduction immediately after stimulation: Low  
Symptom reduction 60 minutes after stimulation: Very Low  
Symptom reduction longer-term use (3 months): Very Low  
Symptom reduction long-term use (greater than 3 months): Very Low

**Conclusion**

Based on review of the currently available clinical literature, there is very
low to low certainty evidence that external upper limb tremor stimulator
therapy (i.e., TAPS therapy) for ET leads to a statistically or clinically
significant reduction in tremor symptoms in the short- or long-term. The two
RCTs comparing TAPS therapy to sham were limited by their small sample sizes
and inconsistency of results, with the larger of the two trials not meeting
its primary endpoint of reduction in tremor symptoms measured by the TETRAS
Archimedes spiral score. Two non-randomized studies were limited by
heterogeneity in baseline patient characteristics (i.e., ET severity and
medication continued through the trial), high dropout rates, and potential
risk of bias in outcome measurement due to the open-label design. Finally, a
real-world evidence study examining the longer-term effectiveness of TAPS was
limited by the substantial amount of missing or excluded data, lack of control
for confounding, and potential bias in patient selection. Of additional note,
the IETF consensus guide was written by three (3) authors and reviewed by IETF
and the editorial team at Guideline Central; however, the guide does not
contain graded recommendations for or against therapeutic options for ET and
did not follow (or did not disclose) a formal methodology, such as Grading of
Recommendations, Assessment, Development, and Evaluation (GRADE).13 As noted
in CMS _Program Integrity Manual_ (Pub. 100-08) Chapter 13, Section 13.2.3
Clinical Guidelines, Consensus Documents and Consultation (in relevant part):
"Acceptance by individual health care providers, or even a limited group of
health care providers, does not indicate general acceptance of the item or
service by the medical community."

In summary, the evidence is insufficient to determine if external upper limb
tremor stimulator therapy improves health outcomes or is reasonable and
necessary in Medicare beneficiaries for the treatment of ET. The Durable
Medical Equipment (DME) Medicare Administrative Contractors (MACs) are aware
that the evidence base remains in evolution. In accordance with CMS _Program
Integrity Manual_ (Pub. 100-08) Chapter 13, Section 13.3.2, peer-reviewed
publication of clinical trial results can be considered in the future.