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Understanding Your Results

Screen Shot 2018-07-11 at 3.37.02 pmVLA Quadscan Parameters

The VLA Quadscan is able to calculate a number of useful parameters that relate to body composition, cellular health and nutrition. It is important to remember that each patient is unique in terms of their body composition and fluid balance and the relative precision of population-based equations and reference ranges used may vary from patient to patient.

The key application of BIA is monitoring change from baseline in each individual person, and a device such as Quadscan with excellent reproducibility is ideal for this purpose.

Establishing a baseline for each patient and regularly assessing them using the VLA Quadscan will allow us to track your health over time and will provide us with an individual assessment will assist in making treatment and nutritional changes that are individualised for you.

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Body Fat: The total mass of adipose tissue. Just some factors that may increase fat mass in patients are excess calorie consumption, a high carbohydrate, diet, lack of exercise, inflammation, chronic stress and hypothyroidism.

Body Lean Mass: Lean body mass (LBM) is the non-fat tissue of the body – muscle tissue, bone, ICW and ECW.

Dry Lean Weight: Lean weight minus TBW. Dry lean weight includes bone and lean tissue. It does not include the Total Body Water (TBW) or ICW. Dry lean weight is useful to track changes in lean tissue, while reducing the influence of body water changes.

Decreases in Body Lean and Dry Lean Weight may be caused by a number of nutritional and catabolic influences, including protein and calorie malnutrition, lack of exercise, stress, inflammation, ageing and other health concerns.

Total Body Water (TBW): The volume of water within the body. TBW is the volume of water mainly in the lean tissue, but a small amount is found in fat tissue. TBW is the sum of the extracellular water (ECW) and Intracellular water (ICW).

Factors that will increase TBW include hydration – drinking adequate fluid, body composition. TBW will be also be increased in a person who has a higher muscle mass.

Extracellular Water (ECW): Extracellular water (ECW) is the fluid found in the extracellular compartment. ECW includes plasma, lymph, and interstitial fluid.

Factors that may increase ECW are inflammation, increased sodium consumption and toxicity. Factors decreasing ECW include dehydration, diuretics and alcohol.

Intracellular Water (ICW): Intracellular water (ICW) is the fluid found inside the cells of lean tissue. Higher levels of ICW are found in people with a higher muscle mass. Higher levels of ICW are correlated with anabolic cellular processes and better health.

Factors increasing ICW include having a good muscle mass, intracellular electrolytes such as potassium and magnesium, sufficient protein and generally good health. Factors that may decrease ICW include low muscle mass, damage to cellular membranes, dehydration and catabolic factors (such as stress and chronic illness).

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Body Cell Mass: Body Cell Mass (BCM) represents the metabolically active component of the lean body mass – in other words, the protein-rich compartment involved in energy expenditure.

BCM consists of: tissue, organs and Intracellular Water (ICW)

Factors that increase BCM include sufficient protein, resistance exercise or increased ICW (losses of ICW due to dehydration can lead to a reduction of the BCM). If a person gains BCM then it is likely to be due to an increase in lean tissue such as muscle mass and/or an increase in ICW within the BCM.

Factors that will reduce the BCM include a reduction in ICW such as lack of intracellular electrolytes, or processes that lead to a loss of muscle tissue such as inflammation, cachexia, ageing, immobility and illness leading to loss of ICW or poor nutrition.

 

3rd Space Water: Total Body Water is calculated at 50 kHz and also at 200 kHz. Both of these frequencies can give a slightly different reading. The 3rd Space Water is the difference between the TBW at 50kHz and the TBW at 200 kHz. Anything over 2 L may indicate fluid retention, while deficits larger than – 2 L may indicate dehydration.

Nutrition Index: The Nutrition Index is the ratio between the Extra-Cellular Water and Total Body Water (ECW/TBW). Anything that increases the ECW will increase this ratio. Anything that lowers BCM such as malnutrition may reduce the ICW and increase this ratio.

 

The Prediction Marker

The Prediction Marker is the ratio between the Impedance measurement at 200 kHz and 5 kHz. This parameter is unique to the VLA Quadscan, with research and clinical evidence demonstrating it as a useful marker of fluid status and/or cell membrane health. A ratio closer to 1 indicates poor cellular health or extreme fluid overload.

The Prediction Marker reflects the influences of the cell membrane and fluid shifts on the electrical properties of the tissue. At 200 kHz the current is strong enough to penetrate the cell membrane and at 5 kHz the current is too weak to penetrate the cell membrane. However, during illness or poor health, the 5 kHz current is able to more easily penetrate the cell membrane, resulting in a smaller resistance value at 5 kHz. As a result, the difference between the impedance value at 5 kHz and 200 kHz is significantly less, resulting in a higher ratio, and a higher Prediction Marker.

 


Prediction Marker Normally lies between 0.700 and 0.820


 

Clinical use has shown that a normal Prediction marker typically lies between 0.700 and 0.820. Anything over 0.820 can indicate a possible fluid imbalance or underlying condition. The most effective way to use the Prediction Marker is to track it over a period of time. The ideal situation is for the Prediction Marker to be measured prior to treatment and this figure used as a benchmark, then measured again during intervention, post treatment and on all subsequent follow up appointments.

Factors that improve the Prediction Marker are exercise, a healthy balance between ICW and ECW, adequate nutrition, adequate antioxidant status, good nutrition and lack of disease. The Prediction Marker is also noted to be lower in some individuals who engaged in heavy sports or exercise in their childhood or teenage years.

 

Phase Angle

Phase angle (PA) is a term used to describe the geometric or mathematical relationship between the ratio of Resistance and Reactance values calculated at the 50 kHZ frequency. The PA represents both the amount and quality of soft tissue (both muscle and fat, although predominantly muscle), although it has also been shown to be an indicator of membrane integrity and water distribution between the intra- and extracellular space and as such is seen as an indicator of health and nutrition.

Higher PA values reflect a larger cellular mass, better cell membrane integrity and better cell function. An average PA in normal healthy people is usually between 5 and 8, however values above 9.5 can be reached in athletes.

In a healthy cell more nutrients and salts enter the cell, therefore the ICW increases. The healthier the cell the healthier the cell membrane. Healthy cell membranes are poor conductors but good capacitors (remember: capacitance is the ability to retain current). The greater the cell’s capacitance, the greater the reactance and PA.

 


An average Phase Angle in normal healthy people is usually between 5 and 8

Athletes can have a Phase Angle of over 9.5 !!


 

When the cell has less ability to store an electrical current, the capacitance of the cell membrane is lower, leading to a lower reactance. A lower reactance will lead to a reduced PA and is indicative of diminished cellular integrity. PA can be improved by increasing the amount of intact cellular membranes (eg. increasing muscle mass through good nutrition and exercise) or by improving cellular health.

Phase angle values vary amongst different populations, an abnormal phase angle in an adult has been proposed to be anything lower than 4.3.

 

What Factors Can Affect Phase Angle?

Age: Phase Angle decreases as we age, often due to the loss of muscle mass and body water and decline in cellular health.

Gender: Men have higher phase angles than women due to the higher amount of muscle mass. Therefore increasing muscle mass is key.

BMI: Phase Angle increases with increasing BMI, due to the increased number of muscle and fat cells. Interestingly, this association is only observed in BMI values <30 kg/m2; in severely obese subjects with BMI >40 kg/ m2, an inverse correlation is found, proposed to be due to the detrimental effects of a large fat mass on cellular health.

Health Status: Disease, inflammation, malnutrition and fluid overload have also been found to lower PA, and as such PA is recognised as a parameter that can be used to assess cellular function.

Factors that may improve the PA include exercise, adequate essential fatty acids, good nutrition, cellular health and mitochondrial function.

 

Bioelectrical Impedance Vector Analysis

Bioelectrical impedance vector analysis (BIVA) is another way to assess the BIA data. The resistance and reactance values are standardised by dividing them by body height, and plotted in the form of a vector graph or impedance graph.

The patient’s impedance vector is then plotted against what is known as a tolerance ellipse, these are reference percentiles (50%, 75%, and 95%) that compare the individual against a healthy reference population of the same gender and race. Healthy individuals are usually located within the 75th tolerance ellipse.

 

How is the BIVA Graph Interpreted?

The position and length of the vector against the tolerance ellipse provides information about hydration status, body cell mass and cell integrity. A migration sideways of the vector (short axis) indicates a decrease or increase of cellular mass (membranes and soft tissues). The length of the vector (longer axis) indicates hydration status from fluid overload (decreased resistance, short vector) to dehydration (increased resistance, longer vector). Vectors that lie outside the tolerance ellipses usually indicate obesity, malnutrition, illness or disease severity.

 

What is the Benefit of the BIVA Graph?

The main benefit of using a BIVA graph is that it does not rely on the use of empirical equations to calculate body composition, instead relying on the raw impedance data.

The graph does not give a numerical estimation of the amount of fat, lean tissue or fluid, instead providing a visual representation of the overall composition. This may be particularly useful in patients who are poorly hydrated or seem to be outside the ‘normal body composition range’, where predictive equations demonstrate less accuracy – eg. in obese or extremely lean subjects.

The movement in the vector position over time can be particularly useful to provide a single point of reference to track health improvements.

 

If you like this article be sure to visit the Spinal Centre website at www.thespinalcentre.com.au and view more content by Dr. Hooper and the Spinal Rehabilitation Team.

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