Brain’s stroke recovery journey

Experts classify the brain’s stroke recovery journey into phases;

  • First 24 hours (hyperacute phase)
  • First 7 days (acute phase)
  • First 3 months (early sub-acute phase)
  • Four – six months (late sub-acute phase)
  • Six months after (chronic phase)

Although experts cage the stroke recovery into phases the whole process is continous but not linear. That means its recovery process is faster in the first three months. Afterwards, it goes into a plateau. In short, the brain’s stroke recovery journey is time-dependent. Experts say this broad time periods vary greatly from person to person. In other words, some may recover the lost movements much faster than others.


Stroke recovery is time-dependent.


The brain’s stroke recovery journey is time-dependent. Therefore, stroke carers should assist in the brain’s hour of need.

Brain’s stroke recovey journey: First 24 hours

Within a few minutes of the stroke attack, the directly affected brain cells who get choked due to lack of oxygen begin to die at a rate of 32,000 neurons per second. However, at the same time, the attack itself alerts neighbouring cells due to reduced oxygen supply. They soon begin rescue efforts. Researchers name this dynamic neighbourhood area “penumbra”. They continue to work hard to recover the jobs previously done by their neighbours who are already dead. Figure 1, which appears in Nature.com illustrates how the penumbra evolves with time.


figure1

Figure 1: How a stroke and its penumbra evolves with time after a block to the middle cerebral artery in mice; source: Nature.com authored by Rudy R.F. et al. (2019) under the license of CC BY 4.0.


First 24 hours: Neighbors’ rescue efforts

Researchers have found that the neighbours in the penumbra would start creating new dendrites, sprouting axons, and even new synapses within the first few hours of the attack. These efforts continue three months, after which the cells slow down their recovery efforts significantly. These new structures become essential for faster recovery. However, evidence also exists that some axon sprouting hamper the ideal recovery; it interfers with the brain’s reorganization efforts. More importantly, behaviour patterns can modify axonal sprouting.

Brain’s stroke recovery journey: First 7 days

On the fifth day of the attack, as much as two-thirds of the brain’s recovery attempts seem to be over. This is because research has shown that two-thirds of movements and sensations that remain six months after the attack appear as early as on the fifth day.

Brain’s stroke recovery journey: First 3 months

However, it has also shown that the brain recovers another 10 per cent between the sixth and 30th day of the attack.

In other words, at the end of the first month, our beloved brain regains 86 per cent of the lost movements and sensations that remain at the end of the sixth month of the attack.

Brain’s stroke recovery journey: First 4-6 months

The salvage attempts of movements and sensations fade away and become minimal after the 90th day.

These facts are not new; researchers uncovered this behaviour of the brain about thirty years ago.

This is how they did it.

In 1989, a team of researchers led by Pamela Duncan closely followed six months a group of 104 US individuals who experienced a stroke for the first time as a result of a block in their carotid arteries. All were in their 40s and above at the time. They grouped the study participants into four groups according to their initial severity level: mild, moderate, moderately severe, and severe. Then, they measured and compared their movements and sensation levels 5 days later, 30 days later, and, finally at the end of 6 months.

The researchers elegantly summarized their findings in the following graph.

Its X-axis represents days after stroke and the Y-axis is the score that quantifies the ability to move arms and legs.

The four horizontal lines that run from left to right – day zero to day 180 (six months) – represent four groups of people who came to the hospital with different causality levels following the attack. The top line indicates the mild casualty group and the lines below to it with worsening casualty levels – moderate, moderate-severe, and severe.

As you can see, the score – the movements – reached closest to its maximum level (86 per cent of the 6-month level) within 30 days – the first month – after the attack and then flattens out.

Keep in mind that this was not the first and last study that reported these findings; similar findings have been reported consistently.

How these findings become useful for stroke carers?

The most important use is that the six-month recovery after the attack can be predicted as early as its fifth day and much better after 30 days. So, you can plan ahead what you may need to assist the affected later. Therefore, this knowledge becomes very useful for stroke carers who help to regain arm & hand movements after stroke.

You can read Pamela Duncan et al’s full paper published in the Stroke Journal through this link: https://www.ahajournals.org/doi/pdf/10.1161/01.STR.23.8.1084

References

  1. Bernhardt J, Hayward KS, Kwakkel G, Ward NS, Wolf SL, Borschmann K, et al. Agreed definitions and a shared vision for new standards in stroke recovery research: The stroke recovery and rehabilitation roundtable taskforce. Int J Stroke. 2017;12(5):444–50. Accessed through this link; https://journals.sagepub.com/doi/full/10.1177/1747493017711816
  2. Duncan P W et al. (1992): Measurement of Motor Recovery After Stroke, Accessed through this link:https://www.ahajournals.org/doi/pdf/10.1161/01.STR.23.8.1084

Author: Prasantha De Silva

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