Thursday, 24 November 2011

Spasticity vs rigidity vs hypertonicity

Hypertonicity: increased resistance to passive lengthening of a muscle. The underlying reason for the hypertonicity is not part of the definition. Hypertonicity could be due to a neural drive problem such as spasticity or rigidity or it could be due to increased resistance due to non contractile element changes in the musculotendinous unit such as contracture.

Spasticity is velocity dependent increased resistance to passive lengthening of the muscle: The faster you stretch the muscle the greater the resistance. Spasticity is clearly neural in nature and is  associated with the upper motor syndrome (UMN). Involvement of the corticospinal tract is often associated with the upper motor unit syndrome and spasticity. There are a number of clinical features that are also associated with spasticity that are part of the upper motor syndrome and some authors consider these features part of spasticity: associated reactions, hypereflexia, flexor synergy in the upper limb and extensor synergy in the lower limb. However including these phenomena as part of spasticity muddies the water so it is better to limit spasticity to velocity dependent resistance.

is increased neural activity throughout the range of muscle excursion and is not velocity dependent: present in both agonist and antagonist. This neural impairment is often associated with basal ganglia disease such as Parkinson’s disease. Lead pipe rigidity describes a constant resistance where when moving a joint resistance is felt and maintains the joint in the altered position. In cogwheel rigidity one feels the resistance rhythmically vary when applying a passive movement. It is thought to be the product of an underlying resting tremor which is masked by the rigidity but can be felt on passive movement.

In TBI you can get all sorts of combinations of neural impairments including spasticity and rigidity. Spasticity in TBI can also be very severe and may well be a somewhat different phenomena to what one sees in conditions like stroke or MS.

NB: Many thanks to gcoe from the physio forum for these definitions!

Saturday, 19 November 2011

The Pinky and the BRAIN

FRONTAL LOBE "Emotional control centre & home to our personality"
  • Motor function/initiation
  • Problem solving/judgement/decision making/reasoning
  • Social and sexual behaviour/impulse control
  • Spontaneity
  • Memory
  • Language

PARIETAL LOBE "What we feel & how we perceive"

1st functional area: Sensation and Perception
  • Integrates sensory information to form a single perception
2nd functional area: Spatial coordinate system 
  • Represents world around us
3rd Somatosensory cortex:
  • Processing of nerve impulses related to: touch, pain, temp, taste, pressure etc (information from mechanoreceptors, chemoreceptors, nociceptors)
TEMPORAL LOBE 'Primary Organisation of Sensory Input'
  • Hearing, Memory, Meaning, Language
  • Interpreting and processing auditory stimuli
  • Play a role in emotion and learning
  • Recognition of words
  • Memory of verbal material
OCCIPITAL LOBE 'Eyes in the back of our head'
  • Brain's ability to recognise objects
  • Vision

    Saturday, 12 November 2011

    Fish Oil (Omega 3) What's the deal?

    One of the most widely talked about supplements by fitness geeks and couch potatoes alike is fish oils. The ratio between omega 6 and omega 3 is out of balance with most in the Western world, said to be between 15-16.7 : 1  (Simopoulos, 2002) when ideally it should be more like 2:1 (the better the ratio the better the health benefits!)

    EFAs are 'essential fatty acids' named as such because we can't produce them in our bodies meaning we need to include them in diet. So we do need both omega 6 and 3 but you've probably got enough 6 from what you already eat (safflower oil, sunflower oil, corn oil) these guys will regularly crop up on the ingredients list of processed foods and are not limited to just plant sources! If you're eating beef from a cow that's grain fed, you got yourself some omega 6 right there (as opposed to the ideal grass fed animals who are higher in omega 3).

    EPA - Eicosapentaenoic acid
    DHA - Docosahexaenoic acid

    These are essential fatty acid components of omega 3 that provide some of the many health benefits derived from fish oil intake. These include:

    1) Improved insulin sensitivity in muscle cells / Decreased insulin sensitivity in fat cells - suggesting that nutrient intake from food would be inclined to protein storage rather than being stored in adipose tissue. This would potentially increase metabolic rate and lean mass (Berardi and Mejia, 2005).

    2) Reduced risk of cardiovascular disease, cancer, diabetes (Simopoulos, 2002)

    3) Improved fetal brain development - the addition of DHA to a pregnant woman's diet may be beneficial for the fetal brain development (Hoffman, 2011)

    EPA and DHA are important components of retina and brain tissue and can help to form neuro-transmitters

    The health benefits are not just limited to the diseases above. Simopoulos (2002) showed in a study that the improved omega 6 to 3 ratio could have beneficial effects on other pathologies. A ratio of 2.5:1 reduced rectal cell proliferation in patients with colorectal cancer compared to a ratio of 4:1 that did not prove to have the same effect. In inflammatory diseases such as rheumatoid arthritis a ratio of 2-3:1 supressed inflammation. A ratio of 5:1 had positive implications on asthma sufferers whereas a ratio of 10:1 showed adverse effects.

    A 'perfect ratio' does not therefore stand out as the diseases listed above are multifactorial and cannot all be improved a universal ratio it would seem. However, the general consensus seems to be that a lower and more balanced ratio of omega 6 to 3 has positive health outcomes whereas a higher omega 6 to 3 can have adverse effects on the body. What's more is taking fish oil as a supplement has no health risks and will only serve to benefit your health (Berardi and Mejia, 2005). So it's a no-brainer guys, if you're not on this stuff already, start taking it or at least start eating more oily fish!

    Does flaxseed have the same benefits as taking fish oil?  

    Apparently not. There are plant sources of omega 3s such as flax, hempseed and walnut oil contain alpha-linoleic acid*. Your body can convert this into EPA and DHA but there is said to be very limited metabolic conversion of dietary alpha-linoleic acid to DHA. These plant sources themselves have no DHA content (Omega 3 institute, 2010).

    *Please note that alpha linoleic acid is not the same thing as alpha lipoic acid which is an antioxidant produced in the body that aids glucose conversion into energy.

    Simopoulos, AP (2002) 'The importance of the ratio of omega-6/omega-3 essential fatty acids', Biomed Pharmacother, 56(8):365-79
    Berardi, J; Mejia, M (2005) 'Scrawny to Brawny' , Rodale, USA