There exists a "critical period" post-stroke where specific neuronal growth factors are upregulated, such as brain-derived neurotrophic factor (BDNF). In fact, the critical period (5-14 days post-stroke) also involves a downregulation of proposed neural growth-inhibiting factors. This combination provides an excellent opportunity for cortical-neuronal regeneration following a stroke.
The problem is that patients recovering from a stroke are alone 60% of the time, and are inactive (sitting or lying in bed) 75% of the time (1). There is also a lack of stimulation and exercise, as most programs only engage patients for one to two hours of their waking day. Clearly, rehabilitation programs are not capitalizing on the timeliness of one's innate enhanced ability to recover from a stroke.
Further to this, in rehabilitation programs centred on upper-limb impairment rehab, patients engaged in a reaching exercise may only reach about 1/10 the amount, as compared to mice with similar impairments. The mice seem to make a significantly better recovery with increased reaching. It seems that the intensity of the stroke recovery program may play a major role in cortical-neuronal regeneration.
Should there be consideration for increased timeliness, duration, and intensity of stroke rehabilitation programs?
(1) Bernhardt et al. Inactive and Alone: Physical Activity Within the First 14 Days of Acute Stroke Unit Care. Stroke, 2004; 35:1005