Archive for November, 2009

“Wireless” Polysomnography?!

Tuesday, November 24th, 2009

Patient being hooked-up with electrodes for a wireless polysomnography on the Sapphire PSG sleep diagnostic system

Hook-up of electrodes for a wireless polysomnography on the Sapphire PSG sleep diagnostic system

At first glance, what do you see in this photo of my friend?

Wires. This struck me as odd (very odd), because my friend was undergoing a wireless polysomnography (sleep test used in sleep disorder diagnosis). To be fair, I already knew that a wireless polysomnography did not mean a polysomnography without wires/electrodes on the patient, nevertheless, I could not help but react at how the term "wireless polysomnography" did not match what I was seeing!

In this article, I want to briefly discuss:

  • A typical polysomnography (PSG)
  • Wireless polysomnography (what makes it wireless while I am seeing all those wires)
  • Some benefits of wireless PSG

    • Polysomnography:

    The patient is hooked-up with sensors to monitor body functions like heart rhythm, brain, eye, and muscle movement, etc during sleep. The sensors plug into a patient-unit also called the jackbox. The jackbox connects to an amplifier, which then connects to the wiring system. The entire sleep lab is hard-wired so that the PSG data travels through the cables from the patient room into the control room, where a sleep technician can monitor the PSG data on a computer.

    Wireless Polysomnography:

    The patient is hooked-up with the standard sensors. The sensors plug into a patient-unit (which integrates the jack-box and amplifiers). The patient-unit wirelessly transmits data to a receiver in the control room where the sleep technician can monitor the PSG data on a computer. But why is this a big deal?

    Benefits of wireless PSG

    While wireless polysomnography is not flawless, it offers distinct advantages:

  • Un-tethered patient - convenient:
    During a typical polysomnography, the patient will need assistance from the technician to unplug the jackbox from the amplifier every time he/she needs to use the restroom or get a drink of water during the night. A wireless polysomnography allows for easy mobility since the patient-unit is not tethered to the wiring cables of the control room.
  • No hard wiring – cost effective:
    Wireless PSG completely eliminates the cost of running cables throughout the facility with its ability to transmit data through multiple walls. Also, there are typically fewer components with wireless devices and lower risk of individual component failure.
  • Portable PSG – cost-effective, convenient:
    With wireless polysomnography, the entire PSG system can be packed into a brief-case of sorts. Setups outside of the lab become more feasible. For example, mobile diagnostic studies in hotels (which is more cost-effective than a sleep lab set-up), hospitals, nursing homes, or patient homes mean that a comprehensive sleep diagnostic service can come to the patient instead of the patient coming to the lab for a PSG. This cuts transportation costs which can be significant for patients who cannot travel unassisted.
  • Expanding the reach of sleep services:
    Overcrowded sleep labs will only have to deal with more complex patients who require in-lab testing, while other patients can be tested off-site. Each patient population can then receive a faster diagnosis and therefore faster treatment initiation, cutting out the need for long waits or investing in additional beds for the sleep lab.

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    Sleep Bling

    Tuesday, November 10th, 2009

    Sapphire PSG (Full PSG): Sleep Bling. What are you wearing tonight?

    Sapphire PSG (Full PSG): Sleep Bling. What are you wearing tonight?

    What are you wearing tonight?

    Sleep Bling :: Sapphire PSG™

    • Wireless
    • Type I
    • 22 channel
    • Full PSG Sleep Platform

    This compact, wireless PSG system integrates the headbox, amplifiers, transducers and data telemetry into one handheld unit. Eliminating the need for separate amplifiers, cables and networking equipment allows for fast set-up and rearrangement. Data storage on a removable SD memory card allows the PSG system to be used for unattended studies or provides immediate data back up. The simplicity of the full PSG system makes it uniquely suited for the traditional sleep lab, as well as non-traditional settings such as inpatient monitoring, “hotel sleep labs” and home testing. With state-of-the-art wireless hardware and CleveMed´s own user-friendly PSG software, Sapphire PSG system manages patient data, data acquisition, scoring and reporting. Six of the 22 channels are EEG channels, fulfilling the requirements for the PSG guidelines. In addition, with two different frequency options built into the sleep monitor system, you are able to choose one best suited to your environment.

    Read more about Sapphire PSG and why it is your ideal PSG System .

    Concept by Joseph Lamont, RPSGT

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    Posted in Sleep Disorders | 3 Comments »

    Gait and Balance Assessment and Therapy in Parkinson’s Disease

    Tuesday, November 3rd, 2009

    Parkinson’s disease is a neurodegenerative disease of the central nervous system and is primarily characterized by cardinal motor symptoms such as tremor, bradykinesia (slowness of movement), and rigidity. Lower extremity symptoms such as gait and balance disturbances (initiating movement, freezing of movement, improper movement form), especially in advanced patients, can be very debilitating, leading to decreased mobility and independence, decreased quality of life, and an increased falling/hip fracture risk [1]. A positive PD diagnosis occurs when a minimum of two cardinal symptoms present themselves. However, less attention is given to gait and balance abnormality as it typically develops in the advanced stages of PD.

    Standard clinical assessment of gait and balance based on a 0 (no severity) – 4 (high severity) scale is performed using a subset of the Unified Parkinson’s Disease Rating Scale (UPDRS) motor section. Tasks typically consist of foot stomping while seated, gait assessment while walking, arising from chair with arms crossed over the chest, and balance assessment while being pulled backwards. As gait is particularly sensitive to ON-OFF therapy state changes in PD and incorporates upper extremity function such as arm swing as well as rigidity and bradykinesia in lower extremities, gait analysis may be a reliable method of assessing overall motor function over time in PD [2].

    When diagnosed with PD, the first line of treatment typically consists of L-Dopa medication to alleviate motor symptoms. However over time, drug effectiveness decreases, requiring the patient to increase dosage. Frequent and stronger side effects such as dyskinesias (uncontrolled arm movement) and unpredictable “on”/”off” episodes are cause for more invasive therapeutic intervention. Deep brain stimulation (DBS) has been widely recognized as an appropriate treatment option when medication no longer adequately alleviates motor symptom severity. Several therapy targets have been established for PD. Subthalamic nucleus (STN) and Globus Pallidus Interna (GPi) stimulation are recognized treatments for sustained improvement in tremor, rigidity, and bradykinesia [3, 4]. However the effects on gait disturbance are less understood. During DBS lead placement and post-evaluation, neurologists adjust several settings: electrode contact configuration and stimulation parameters (frequency, pulse width, and amplitude). Studies show that while high-frequency/high voltage stimulation improves cardinal symptoms, patients exhibit increased frequency of freezing episodes. However, stimulation at lower frequencies has demonstrated improved gait [5].

    New PD gait therapies are being researched and developed and existing interventions further established. Another DBS target, the pedunculopontine nucleus (PPN), located near the brain stem plays an important role in locomotion function in animal models, specifically initiation and modulation of gait [6-8]. Patients with advanced stages of PD only exhibit mild improvement of freezing with standard medication such as L-Dopa [9, 10]. Preliminary studies of PPN surgeries off-medication marked a significant improvement of the UPDRS motor exam section III, specifically gait and postural qualities. In addition, the combination of STN and PPN DBS resulted in a further significant improvement. Despite promising results, PPN surgical intervention is currently in its infancy as little is known about the nucleus’ function in humans and how well animal model testing translates to human clinical trials [7].

    1. Cattaneo, D., et al., Risks of falls in subjects with multiple sclerosis. Arch Phys Med Rehabil, 2002. 83(6): p. 864-7.
    2. Salarian, A., et al., Gait assessment in Parkinson’s disease: toward an ambulatory system for long-term monitoring. IEEE Trans Biomed Eng, 2004. 51(8): p. 1434-43.
    3. Hamani, C., et al., Bilateral subthalamic nucleus stimulation for Parkinson’s disease: a systematic review of the clinical literature. Neurosurgery, 2005. 56(6): p. 1313-21; discussion 1321-4.
    4. Krack, P., et al., Five-year follow-up of bilateral stimulation of the subthalamic nucleus in advanced Parkinson’s disease. N Engl J Med, 2003. 349(20): p. 1925-34.
    5. Moreau, C., et al., STN-DBS frequency effects on freezing of gait in advanced Parkinson disease. Neurology, 2008. 71(2): p. 80-4.
    6. Garcia-Rill, E., et al., Locomotion-inducing sites in the vicinity of the pedunculopontine nucleus. Brain Res Bull, 1987. 18(6): p. 731-8.
    7. Pahapill, P.A., et al., The pedunculopontine nucleus and Parkinson’s disease. Brain, 2000. 123 ( Pt 9): p. 1767-83.
    8. Skinner, R.D., et al., Locomotor projections from the pedunculopontine nucleus to the spinal cord. Neuroreport, 1990. 1(3-4): p. 183-6.
    9. Pullman, S.L., et al., Dopaminergic effects on simple and choice reaction time performance in Parkinson’s disease. Neurology, 1988. 38(2): p. 249-54.
    10. Starkstein, S.E., et al., Evoked potentials, reaction time and cognitive performance in on and off phases of Parkinson’s disease. J Neurol Neurosurg Psychiatry, 1989. 52(3): p. 338-40.

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    Posted in Movement Disorders | 3 Comments »