PLoS One. 2014 Aug 4;9(8):e103211. doi: 10.1371/journal.pone.0103211.

Gait velocity is an indicator of cognitive performance in healthy middle-aged adults.

Jabourian A1, Lancrenon S2, Delva C2, Perreve-Genet A3, Lablanchy JP4, Jabourian M1.
  • 1Laboratory of Clinical Neurophysiology, Paris, France.
  • 2SYLIA-STAT, Bourg la Reine, France.
  • 3Center of Cardiology, Paris, France.
  • 4Center of Psychiatry, Paris, France.

 

Abstract

Psychomotor retardation, especially motor and cognitive slowing down, has been described many times in the elderly but to our knowledge, has never been examined in healthy middle-aged adults. The present study explores whether walking time may provide an early signal of cognitive performance, using 266 healthy adults ([18-65] years old, mean age: 45.7±12.9 years) who were also subdivided in 2 groups: under or over 50. Walking time (50 meters) and cognitive performances (mini-mental state examination, Benton Visual Retention Test and Rey Complex Figure) were assessed; total psychometric score was the sum of individual test scores. Analyses were controlled for age, gender, education level, height and weight. The mean psychometric scores were within the normal range. A substantial proportion of subjects exhibited low performance in some aspects of visuospatial memory, particularly in the older subset. In the total population, walking time was negatively correlated with all cognitive tests, particularly to total psychometric score (R = -0.817, p<0.0001); the unique contribution of walking time on all cognitive scores was very high (delta R-squared = 0.496). In the older subset, performances on walk and cognition were lower than in the younger subset. Total psychometric score showed the strongest correlation with walking time in the older subset (R = -0.867; p<0.001). In all subsets, walking time was the main explanatory variable of the total psychometric score (delta R-squared: ≤ 49 = 0.361; ≥50 = 0.613). These findings indicate that i) a significant proportion of adults without cognitive complaints exhibit low cognitive performance including visuospatial memory and longer walking time, ii) cognitive functioning is strongly correlated to walking time in healthy middle-aged adults, iii) gait velocity (GV) could be an indicator of cognitive performance in some important cognitive domains. These results warrant further investigation because such data may represent a marker for the detection of middle-aged adults who are at risk for further cognitive decline.

PMID: 25089518

 

Supplements:

Global slowing down and rarefaction of motoric and mental activities have been described by Hippocrate and Arethée of Cesare respectively 4th century BC and the first century AC. Studies were made essentially in melancholia or other depressive disorders but not in cognitive decline. Until recently, cognitive motoric retardation was overlooked or attributed to normal aging process. Prior to early 2000s, walking characteristics were analyzed only in neurologic or locomotion disorders. However, as early as 1995, our research on brain/mental and heart disorders in thousands of patients revealed an important association between cognition and gait velocity.

Medical assessment of these patients included a thorough neurologic and psychiatric examination, a simple clinical bedside procedure detecting and quantifying cognitive and motor retardation (walking speed and three cognitive tests as described in Jabourian et al 2014) and neurocardio electrophysiological testings. Two interconnected discoveries were revealed:

a- Walking speed was a reliable indicator of the cognitive status. This concept was verified and patented (French and US Patent 1996 -1997). Surprisingly this relationship was also high in healthy adults (French and European patent 2010, Jabourian et al 2014).

b- In cardiac arrhythmia patients, 60% presented a cognitive decline, 40% of them were demented. Walking speed, cognitive performance and EEG as well as other sensory and neuropsychiatric signs were evolving in a parallel way either in their decline or in their spectacular and unhoped recovery after the correction of arrhythmia, suggesting the existence of an arrhythmogenic cognitive decline or dementia. Arrhythmogenic dementias are usually underestimated while Alzheimer’s dementia might be overdiagnosed. Diagnosing a cryptic paroxysmal cardiac arrhythmia which causes neuropsychiatric disorders and cognitive decline is not easy. Whereas cerebral chronic hypoperfusion is comprehensible in chronic arrhythmias, it is less in paroxysmal arrhythmias where other causes may be involved, such as modification of neural or metabolic processes or even kindling phenomenon. Research targeting this curable or amenable dementia remains very poor.

Conversely, the concept of walking speed as an indicator or a predictor of dementia in the elderly had been very prosperous. After 2006, it became an avenue for researchers all over the world. It had been analyzed in all its facets and labelled with different logos such as “Motoric Cognitive Risk Syndrom” or “ Motoric Signature of MCI” etc. Whatever the appellation, the huge research made on walking speed and cognition in elderly did confirm and validate the walking test that we had described in 1997.The walking test is now unanimously recognized as a screening test detecting a cognitive decline which needs to be confirmed and quantified with a neurocognitive assessment.

The next step should be the early identification of an aetiopathogenic cause of the cognitive decline, but we do not have the ideal knowledge for it. To date, even the different subtypes of MCIs cannot help prediction of the causes underlying motoric cognitive decline. However, the array of new conceptual and methodological approaches should help the causal diagnosis.

Below are 3 important concepts that we would like to share.

1- Fast walking speed may be an earlier marker of cognitive decline than usual walking speed. Usual walking speed has an important interindividual variability; moreover it remains stable until the eighties. At the opposite, fast walking speed decreases as soon as the fifties and even earlier (Bohannon 1997). Fast walking speed with or without turning or dual tasks involves larger and more sophisticated brain processes than usual walking (Desphande et al. 2009).We have patented a device, immediately indicating to the physicians during a routine medical examination if the cognitive performance is normal, abnormal or questionable (French and European patents, US patents applications).

2- Detection of “Brain at Risk” should be made much earlier in life and in normal population as suggested by Hachinski and Bowler 1993 and many others and supported by our results in Jabourian et al. 2014. Our device testing an individual’s walking speed and cognition described above will be a useful screening tool for epidemiologists and clinicians, even in healthy adults as soon as the fifties and even earlier.

3- Psychiatric assessments and neurocardio electrophysiological investigations should systematically be included in the medical assessment. Indeed, psychiatric as well as electrophysiological signs may be early indicators of mental and cognitive frailties.

 

 MJ fig1

Figure 1

Here is an example of a clinical case illustrating these new and interesting concepts. A 53 year old retired teacher was brought by her family for fits of paranoid delusions associated to several non-accidental and unexplained falls. These episodes lasted few days. She had 5 episodes in 18 months. At the first presentation in 1997, walking speed was low and the copy of the Rey figure showed some mild errors (small rectangle on the left side is wrongly located) (Figure 1). qEEG exhibited a decrease in alpha rhythm power. The paroxysmal character of these associated symptoms suggested the probability of transient cardiac arrhythmia. Rhythmologic investigations were prescribed but not done. 18 months later, she was in a demented state with worsening of qEEG parameters. Figure 2 is illustrative. Eventually, atrial fibrillation with paroxysmal atrioventricular bloc were found. Figure 3 shows the cognitive and motoric recovery after pacemaker implantation.

MJ fig2

Figure 2

MJ fig3

Figure 3

 

In conclusion, fast walking test is the first stage in detecting cognitive decline, even in apparently healthy middle-aged adults. The second step is the quantification of the cognitive decline; it may be mild or more severe. The third stage is the aetiopathogenic diagnosis of the motoric cognitive decline and the detection of curable forms. Among the vascular factors, cardiac arrhythmias have a particular importance. Future research needs the array of new approaches integrating not only neurology but also psychiatry and neurocardio electrophysiology.

 

References

  • Bohannon RW (1997) Comfortable and maximum walking speed of adults aged 20-79 years: reference values and determinants. Age Ageing 26: 15-9.
  • Deshpande N, Metter EJ, Bandinelli S, Guralnik J, Ferrucci L (2009) Gait speed under varied challenges and cognitive decline in older persons: a prospective study. Age and Ageing 38: 509-514.
  • Hachinski VC, Bowler JV (1993) Vascular Dementia. Neurology 43: 2159-2160.
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