IPSJ SIG Technical Report

Quick Screening Mild Cognitive Impairment and
Dementia using Quantitative Evaluation of Motor
Control Function
Kyota Aoki1

Kenji Niijima2

Tsutomu Yoshioka3

Abstract: The Visual synchronization task (VST) evaluates the motor control function, generates evaluation
parameters, and takes only 25 seconds to complete. Evaluation parameters of the VST were tested as predictors of micro cognitive impairment (MCI) and dementia. The mean rotation speed parameter decreased inorder of control, MCI, and dementia groups. With the mean rotation speed parameters of right hand in thefirst period (represented as AveP3rR1), p-value of t-test between the control group and the dementia groupis 8.37 × 10−13 , and AUC is 0.863. Between the control and dementia groups with 0.765 as a cut-oﬀ valueof the AveP3rR1, specificity is 0.84 and sensitivity is 0.77. Using the mean rotation speed of the right handin the first period as the evaluating parameter, the VST can be measured in less than 15 seconds, whichenables an easy screening for MCI.
Keywords: Dementia, Micro cognitive impairment (MCI), quick diagnosis, motor control function evaluation
method, precise quantitative evaluation

1.

Introduction

This study proposes probable parameters for screeningof brain disorders including dementia and micro cognitive
impairment (MCI) using the motor control function evaluation method called visual synchronization tasks (VST).
Japan has an increasingly aging society, in which 28.1% of
the population is composed of elderly people [1], [2]. Dementia is the most common age-related neurodegenerative disease and therefore, the health, social and economic impact
resulting from dementia will continue to increase alongside
the longevity of the population. The prevalence rate of dementia is estimated to be around 10% in the elderly people
in Japan. Alzheimer’s disease is most common cause of dementia and currently an irreversible process with treatmentsthat only slow the progression of the condition [3].
Minimal mental state examination (MMSE) is the mostcommonly used scale for the detection of Alzheimer’s disease and other dementia [4], while the VST evaluates many
aspects of brain functions [5], [6], [7], [8], and is eﬀective
index for the development of brain function in elementary
school students [9], [10], [11]. It has also been shown that
the VST is an eﬀective indicator of brain function decline inolder people [12], [13].
This paper discusses the eﬀects of MCI and dementia on
motor control function measured by the VST [5]. The mo1
2
3

Utsunomiya, Tochigi 320-0061, Japan
Niijima Internal Medicine Clinic, Shimotsuke, Tochigi 3290507, Japan
Soft CDC Corp., Utsunomiya, Tochigi 320-0861, Japanc 1993 Information Processing Society of Japan⃝

tor control function evaluation method is safe, simple, andnon-invasive; it does not require special equipment that attaches to the patient’s body and is conducted in 25 seconds
in the seated position, without the requirement of global
movements. The method is easy to complete. It needs only
25 seconds, and is performed in seated position. No global
movements are needed.
In this paper, we will introduce the measurement method,patients, and control group construction. Then, the analysis
and proper parameters to evaluate the eﬀect of MCI and dementia will be reported and discussed using the experimental data. And last, the findings and impact of our findings
will be highlighted.

2.

Method2.1 Measurement session
One measurement session was conducted to evaluate theeﬀect of dementia is using the VST. The brain performanceis evaluated and compared to the motor control function aspart of the VST.
A VST can be completed in 25 S. Fig. 1 shows the structure of a visual synchronization task. One VST is constructed in two stages. In the first stage, stimulus movement
is displayed and in the second stage, no stimulus movement
is displayed. The subject rotates their hands as the stimulus
movement with and without displayed stimulus movement.
The proposed method enables the fast screening of thebrain dysfunctions including MCI and the dementia. The
VST can determine MCI probability at very low cost andIPSJ SIG Technical Report

The mean age of the participants included in the trials was
71.2 years old.
The dementia group included 70 trials and 21 participants. The mean age of the participants in these trials was
83.8 years old.

Fig. 1

Structure of the visual synchronization task
(Relations between stimulus and analysis periods).

may be useful as an initial screen for MCI and dementia.

3.

Basic measurement parameters

3.1 Evaluation parameters
At each stimulus cycle of the VST, non-smoothness measure (NSM), the phase of the participant’s movement synchronized with the stimulus movement, and the power ofthe participant’s movement synchronized with the stimulus
movement were calculated. The Power of three cycles inratio (P3r) was obtained at each of the three continuous
stimulus cycles and was calculated as follows: The moving
speed P 3r (Power of 3 cycles in Ratio) was defined as (1).
P 3r is the power of stimulus in lower 3 components in ratio.
P 3r =P 33
P 31 + P 32 + P 33

(1)

In (1), P 3n represents the power of the n/3 Hz component
at each of the three continuous stimulus cycles. When a participant follows the stimulus movement completely, there isno slower movements. P 31 and P 32 are zero and therefore,
P 3r is 1.0.
3.2 Evaluation parameters at each period
The first and second stages together have a total of four
periods. At each period, statistical parameters for NSM,
the phase in which the participant’s movement synchronizedwith the stimulus movement, and the power of the participant’s movement synchronized with the stimulus movement,that are listed below.
• Mean• Median• Lower quartile• Minimum• Fluctuation range• Standard deviation
Only the mean was calculated for P3r.
3.3 MCI and Dementia groups
VST trials were conducted with permission from the Utsunomiya University Ethical Council.
The participants of 100 VST trials had undergone the
MMSE (Minimal Mental State Examination). The participants with MMSE total under 28 and over 23 were includedin the MCI group. Those with MMSE scores equal or under
23 were included in the dementia group.
The MCI group included 30 VST trials and 6 participants.

c 1993 Information Processing Society of Japan⃝

3.4 Control population
From the VST participants, those within normal limits,with only high blood pressure, and Hyperlipidemia were selected as the candidate control group, which included 763
VST trials and 172 participants. From their medical records,
about 60% of the subjects had no neurological problems andtherefore, were selected as healthy subjects.
3.4.1 Age
Motor control function degrades with the aging process[12], [13]. The candidate control group included more relatively young people than the MCI group. To compensate
the diﬀerence in age, the participants under 58 years old
were removed from the candidate control group, resulting
candidate control group included 374 trials. The group’s
average age was 71.5 years old, which was similar to themean ages of the MCI group and included 143 participants.
The number of within normal limit (WNL) participants was
15 and included 47 trials. The number of high blood pressure participants was 90 and included 240 trials. There were38 Hyperlipidemia participants who comprised 87 trials.
3.4.2 Diﬀerence of rotation between both hands
Healthy peoples have no diﬃculties rotating their hands instimulus 1 Hz supination/pronation movements, with both
hands synchronized. In healthy peoples, the diﬀerences in
the movements between both hands are small and therefore,
the large diﬀerences between the rotations of both hands indicates problems with the measurements or the executionsof the trials. Outliers were removed based on the movement
diﬀerences between hands. Diﬀerences in the rotation powers synchronizing the 1 Hz stimulus movements (represented
P 33 in (1)) between hands in the first period are shown in
the left panel of Fig. 2. In a box plot of this paper, the box
is drawn from Q1(first quartile) to Q3(third quartile) witha horizontal line drawn in the middle to denote the median.
The whiskers extend to the most extreme data point which
is no more than 1.5 times the inter quartile range from thebox.
In the candidate control group, the trials out 3σ from themedian were removed. This process was repeated until thegroup was fixed, resulting in 335 trials and 140 participants.
The standard derivation of the diﬀerences in rotation powers between both hands in the first period of the resulting
candidate control group was 1159.4, with a mean of 438.7.
The same steps were repeated in the second and third
periods, resulting in 300 trials and 132 participants. The
standard derivation of the diﬀerences of rotation speeds ofboth hands in the first period of the resulting candidate control group was 1427.0, with mean of 626.6 and a median of
380.1. The diﬀerences of the rotation powers in the first
period distribution is shown in the right panel of Fig. 2.

3

IPSJ SIG Technical Report

Fig. 3Fig. 2The change of the distributions of the diﬀerences of rotation powers between hands in the first period in 341 pairsof a candidate control group and the distributions after
the processing.
(The candidate control group before the processing is on
the left, and the one after the processing is on the right.)

The average ages of the candidate control group was 71.5
years old and the number of WNL participants was 14 andincluded 39 trials. The number of participants with highblood pressure was 84 and included 199 trials, while there
were 34 participants with hyperlipidemia, who participatedin 62 trials.
3.4.3 Outliers removals for mean P3r of the righthand in the first period
Health people able to rotate their hands in a synchronizedmanner to stimulus images. In these cases, the mean P3r of
the right hand in the first period (AveP3rR1) represented
the speed of rotations based on the stimulus rotations andwas kept relatively high. The mean AveP3rR1 of the candidate control group was 0.783, with a standard derivation is0.139.
The candidate control group included some outliers;
therefore, the candidate control group was reduced with
AveP3rR1. The number of pairs in the candidate control
group was 270, with a mean of 0.82 and a standard derivation of 0.086.
3.4.4 Outliers removals for mean NSM of theright hand in the first period
With the stimulus images, healthy peoples enables to rotate their hands synchronizing the stimulus images. In thesecases, the NSM (non smoothness measure) that represents
the degree of non-synchronization with the stimulus rotations and was relatively low.
The mean was 0.464 and had a standard derivation of
0.103.
To remove outliers from the group, the candidate control
group was reduced so that it had a mean NSM to that of
the first period. The number of trials in the resulting groupwas 251, which included 122 participants.
3.4.5 Outliers removals for mean P3r of the righthand in the first period again
With the stimulus images, healthy peoples enables to rotate their hands synchronizing the stimulus images. In thecases, the AveP3rR1 are kept relatively high. In the firstc 1993 Information Processing Society of Japan⃝The distributions of ages in the control, MCI, and dementia groups.

period of the VST, a stimulus image is proposed.
Some outliers were left in the candidate control group.
Therefore, the candidate control group was reduced as theprevious step with the mean of P3rs in the first period.
The statistical values before the processing are listed below. The mean was 0.830. The standard derivation is 0.076.
Apparently the group included some outliers.
The statistical values after the processing are listed below.
The number trials was 244.The number of participants was
121. The mean of the mean of P3rs of the first period of thegroup was 0.836. The standard derivation was 0.069.
The candidate control group included 300 trials and 244
trials after processing. About 19% of the initial trials in thecandidate control group were removed and reveals a ratiothat was smaller than the 40% that were estimated fromthe daily clinical study. We used this reduced candidate
control group for all further analyses.
The distributions of the ages of the groups are shown in
Fig. 3. The age distributions both of the control and MCI
groups were nearly same while that of the dementia group
was older than the control and MCI groups.

4.

Screening parameters for MCI detection

The boundary between healthy individuals and those with
MCI is not clear. The screening target population consisted of healthy individuals, MCIs, and dementias. Evenif a screening method had enough power to identify probable MCI, if it overlooks dementia is not reliable. Therefore,
we aimed to develop parameters could detect dementia withhigh probability and screen for probable MCI from healthypeoples.
4.1 Parameter evaluation criteria
121 valid healthy participants and 21 valid dementia participants were used for statistical analysis. However, six
valid MCI participants were not enough for simple statistical evaluation. Therefore, between the healthy and dementia groups, the statistical diﬀerences were evaluated using a
T-test and ROC (receiver operating characteristic) analysis.
The distribution status of the control and test groups werevisualized using a box plot.
Between healthy group and dementia group, p-value andAUC (area under curve) used as indicators of screening

IPSJ SIG Technical Report

power. Among the healthy, MCI, and dementia groups, thegradual distribution changes reflected the stability of theresults, which indicated using a box plot.
4.2 Candidate parameter selection
The AUC and p-value of all parameters between the control and the dementia groups are listed in Table 1. They
are plotted in Fig. 4.

Fig. 4

AUC and p-values between the control and the dementia
groups.

In Table 1, the first three characters represent the typeof statistics. ”Ave” represents the mean in a period, ”min”
indicates the minimum in a period. The diﬀerence and standard derivation of the results are indicated by ”Dif” and”Qua”, respectively.
The second three characters represent the type of parameter, including the non-smoothness measure (NSM), rotation
power synchronized with the stimulus movement (PWP),
the rotation speed defined by formula (1) (P3r), and therotation power synchronized with three continuous stimulus
movement cycles (P3P).
The last two characters represent left(L) or right(R) hand,
while the first, second, third, and fourth periods are indicated with 1, 2, 3, or 4, respectively.
The p-value and the AUC were inversely correlated with
one another (Fig. 4). From the distribution, the parametersthat had p-values that were smaller than 1e − 10 and an
AUC that was larger than 0.85 were examined in detail.
The selected parameters included AveP3rL2, AveP3rL3,
AveP3rR2, AveP3rL1, and AveP3rR1, which represented
the rotation speed in the first, second, and third periods.
4.3

Discussions based on The distributions ofhealthy, MCI, and dementia groups
Fig. 5 shows a box diagram of the means of the rotationc 1993 Information Processing Society of Japan⃝

Table 1

AUCs and p-values of a t-test between the control groupand dementia group and AUCs of the MCI group.
Parameter
AveP3rL2
AveP3rL3
AveP3rR2
AveP3rL1
AveP3rR3
AveP3PL3
AveP3PR3
AveP3rR1
AveP3PL2
minPWPL1
AveP3PR2
minPWPR1
AveP3PL1
AveP3PR1
minPWPR2
DifPWPL1
AvePWPR1
StdPWPL1
minPWPL2
DifPWPR1
DifPWPR2
StdPWPR1
StdPWPR2
AvePWPR3
QuaNSMR1
QuaPWPR1
AvePWPR2
MedNSMR1
QuaPWPR2
QuaPWPL1
QuaPWPL2
StdPWPL2
MedPWPR1
AveNSMR1
DifPWPL2
QuaNSMR3
minNSMR3AvePWPL2
QuaNSML1
minNSMR1
MedNSML1
AvePWPL1
AveNSML2
MedPWPL1
MedNSMR2MedPWPR2
AveNSML1
minNSMR2
DifNSML1
MedNSML2
MedPWPL2
StdNSML1
AveP3rL4
minNSML1
StdNSMR2
DifNSML2
AveP3PL4
StdNSML2
AveNSMR2
QuaNSMR2MedNSMR2
QuaNSMR2
minNSML2
QuaNSML2
MedNSMR3
AveNSMR3
DifNSMR1
StdNSMR1
AveP3rR4
AveP3PR4
AveNSMR4
StdNSMR3
DifNSMR3
AveNSMR2

DementiaAUC
0.885
0.892
0.858
0.868
0.847
0.820
0.824
0.863
0.820
0.810
0.824
0.827
0.806
0.822
0.787
0.858
0.758
0.856
0.757
0.825
0.818
0.824
0.825
0.759
0.852
0.746
0.775
0.854
0.771
0.737
0.737
0.786
0.722
0.882
0.777
0.799
0.755
0.729
0.842
0.767
0.846
0.701
0.818
0.699
0.796
0.720
0.862
0.728
0.826
0.804
0.701
0.825
0.167
0.775
0.811
0.824
0.167
0.821
0.757
0.770
0.753
0.749
0.692
0.741
0.812
0.821
0.837
0.834
0.164
0.163
0.743
0.771
0.770
0.822

Dementia
p-value
2.2×10−16
2.2×10−16
2.7×10−16
1.0×10−15
5.9×10−15
1.3×10−13
1.6×10−13
8.4×10−13
1.3×10−12
1.8×10−12
2.1×10−12
2.6×10−12
1.4×10−11
1.9×10−11
1.2×10−10
1.1×10−09
1.4×10−09
1.8×10−09
1.8×10−09
2.1×10−09
2.2×10−09
3.2×10−09
3.3×10−09
5.5×10−09
1.0×10−08
1.1×10−08
1.2×10−08
2.3×10−08
3.2×10−08
5.7×10−08
9.2×10−08
9.2×10−08
1.1×10−07
1.6×10−07
1.7×10−07
2.8×10−07
3.2×10−07
3.8×10−07
5.9×10−07
7.5×10−07
1.7×10−06
1.8×10−06
2.5×10−06
2.6×10−06
3.3×10−06
4.3×10−06
4.6×10−06
1.0×10−05
1.1×10−05
1.3×10−05
1.6×10−05
2.5×10−05
2.5×10−05
2.9×10−05
3.0×10−05
6.1×10−05
7.6×10−05
8.4×10−05
8.9×10−05
1.1×10−04
1.1×10−04
1.2×10−04
1.5×10−04
2.1×10−04
4.9×10−04
8.0×10−04
1.2×10−03
1.6×10−03
1.9×10−03
3.4×10−03
1.2×10−02
1.8×10−02
1.9×10−02
1.5×10−01

MCIAUC
0.735
0.730
0.683
0.718
0.688
0.599
0.544
0.802
0.601
0.633
0.518
0.624
0.606
0.605
0.507
0.704
0.514
0.703
0.550
0.747
0.620
0.752
0.621
0.548
0.809
0.503
0.483
0.844
0.463
0.506
0.430
0.718
0.477
0.856
0.719
0.654
0.645
0.544
0.792
0.744
0.791
0.545
0.703
0.530
0.710
0.447
0.760
0.670
0.725
0.706
0.608
0.725
0.166
0.746
0.662
0.697
0.156
0.701
0.856
0.673
0.844
0.809
0.709
0.689
0.640
0.656
0.856
0.856
0.159
0.157
0.650
0.651
0.656
0.683

5

IPSJ SIG Technical Report

Table 2
Cutoﬀ
value
0.733
0.734
0.737
0.741
0.742
0.744
0.748
0.749
0.756
0.757
0.765
0.768
0.769
0.774
0.775
0.778
0.779
0.782
0.785
0.786
0.787
0.788
0.792
0.795
0.797

ROC analysis among the control, MCI, and dementia
groups.
Cont.
spec.
0.873
0.869
0.865
0.865
0.865
0.857
0.852
0.848
0.844
0.844
0.844
0.840
0.840
0.836
0.832
0.828
0.824
0.824
0.820
0.816
0.816
0.811
0.807
0.807
0.803

MCI
sens.
0.500
0.500
0.500
0.500
0.500
0.500
0.500
0.500
0.500
0.500
0.500
0.500
0.533
0.533
0.533
0.533
0.533
0.533
0.533
0.533
0.567
0.567
0.567
0.600
0.600

Dementia
sens.
0.700
0.700
0.700
0.714
0.729
0.729
0.729
0.743
0.743
0.757
0.771
0.771
0.771
0.771
0.771
0.771
0.771
0.786
0.786
0.786
0.786
0.786
0.786
0.786
0.786

MCI
+Cont.
1.373
1.369
1.365
1.365
1.365
1.357
1.352
1.348
1.344
1.344
1.344
1.340
1.373
1.369
1.365
1.361
1.357
1.357
1.353
1.349
1.382
1.378
1.374
1.407
1.403

Dementia+Cont.
1.573
1.569
1.565
1.579
1.593
1.585
1.581
1.591
1.587
1.601
1.616
1.612
1.612
1.607
1.603
1.599
1.595
1.609
1.605
1.601
1.601
1.597
1.593
1.593
1.589

speed measurements of the right hand in the first period of
the control, MCI, and dementia groups, while those fromthe second and third periods are presented in Fig. 6 andFig. 7, respectively.
Healthy and MCI, and MCI and dementia are adjacentconcepts, and their pathological conditions change continuously. Therefore, for screening probable MCI participantsfrom healthy peoples, the gradual parameter change fromhealthy, MCI, and dementia groups respectively, was preferable.
Fig. 5, Fig. 6, and Fig. 7, overlap between the control
and MCI groups increased, respectively, indicating that themean rotation speed measurements of the right hand in thefirst period was most preferred. Other selected parameters
may be better than AveP3rR1; however, for screening MCI
and dementia from healthy people in the fourth period of
the VST did not fit. Therefore, to screen for MCI and dementia, the fourth period of the VST should be omitted,
suggesting that the VST can be shortened into 20-s trials.
4.4 Behavior of AveP3rR1
With the mean rotation speed measurement of the righthand in the first period, ROC between the control and dementia groups were calculated (Fig. 8). The AUC of the
ROC was 0.86. Table 2 shows the relationship among the
cut-oﬀ values for the control, MCI, and dementia groups, indicating the best value for MCI and dementia identification.
Using 0.765 as a cut-oﬀ value, the specificity was 0.84 andthe sensitivity was 0.77. The sum of the specificity of thecontrol group and the sensitivity of the dementia group was
1.62. Around the 0.765 of the cut-oﬀ value, the sums of
the specificity of the control group and the sensitivity of thedementia group remained large.

c 1993 Information Processing Society of Japan⃝The ROC between the control and MCI groups are shownwith respect to the mean rotation speed measurement of theright hand in the first period (Fig. 9). AUC of the ROC was
0.802, with a cut-oﬀ value of 0.765, a specificity was 0.84 anda sensitivity was 0.77. The sum of the specificity of the control group and the sensitivity of the dementia group was
1.62.

Fig. 5

Mean of the rotation speed measures represented by P3rof the control, the MCI and the dementia groups in thefirst period.

Fig. 6

Mean of the rotation speed measures represented by P3rof the control, the MCI and the dementia groups in thesecond period.

Fig. 7

Mean of the rotation speed measures represented by P3rof the control, the MCI and the dementia groups in thethird period.

IPSJ SIG Technical Report

The control and MCI groups were adjacent, and theirboundaries were not clear.
Using the mean rotation speed measurement of the righthand in the first period, VST trial can be shortened to lessthan 15 seconds in the first and second periods, which makes
the VST trials easier to administer.

screening for probable MCI in healthy cohorts. The number of participants of dementia was 26 , while the numberof healthy participants was 199. These are large enough tostatistical analysis and therefore, the eﬀective parameters
would work for screening MCI and dementia from a healthy
population.
The VST took only 15 seconds, which is enough to measure eﬀective parameters in the first period for screening forprobable MCI cases when compared with the healthy group.
This optimized VST is safe, not addictive, and easy to complete, making it an excellent tool for easily screening for
MCI among otherwise healthy individuals.
References
[1]
[2]
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[4]

Fig. 8

ROC analysis comparing the control and dementia groups
for AveP3rR1.
[5]

[6]

[7]

[8]

[9]

Fig. 95.

ROC analysis comparing the control and MCI groups for
AveP3rR1.

Conclusion

This study proposes eﬀective parameters for screening for
MCI and dementia from healthy people using the VST. The
rotation speed parameters in the first, second, and third periods were eﬀective at identifying MCI and dementia fromhealthy controls. Of the parameters, the rotation speed in
the first period was the most eﬀective at identifying MCI
and dementia in this study.
However, the number of participants in the MCI group
was only seven; therefore, large scale experiments are needed
to clarify the detailed characteristics of parameters forc 1993 Information Processing Society of Japan
⃝

[10]

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Aoki, K.: Mental Fatigue Measurement using Visual Synchronization Tasks, Proceedings of the 6th International
Conference on Bioinformatics and Biomedical Science, pp.
37–43. (2017).
Aoki, K., Hotta, H., Otabe, N., Fukuda, N., Harada, K.:
MOTOR SKILL DEVELOPMENTS IN 6 TO 12 YEARSOLD GIRLS WITH VISUAL SYNCHRONIZATION TASK,2016 Hawaii International Conference on Education, Honolulu, USA, 2016, pp. 953–959, ISSN#:1541–5880, (2016)
Aoki, K., Fukuda, Y., Harada, K.: DEVELOPMENTS OF
MOTOR CONTROL FUNCTION IN PRIMARY SCHOOLAGES AND JUNIOR HIGH SCHOOL AGES, HICE2019,
January 2019, Hawaii, USA, Conference Proceedings of
Hawaii International Conference on Education, pp. 611–626,
ISSN# 1541–5880. (2019)
Aoki, K., Fukuda, N., Hotta, H.: Gender Diﬀerence of Developments of Motor Control Function in Primary School Ages
with Visual Synchronization Task of Hands’ Movements, International Journal of Social Science and Humanity, Vol.7,
No.5, pp.269–273. (2017).
Aoki, K., Hotta, H.: Aging Measurements with Precise Observations of Synchronization Hands Movements -Aging effects about motor control function-, Global Health Challenges 2016, pp.49–55, October 9–13, 2016 - Venice, Italy,
IARIA, ISBN: 978-1-61208-511-1, (2016).
Aoki, K., Hotta, H.: Development and Aging on Motor Control Function with Precise Observations of Synchronization
Hands Movements, Journal of Life Sciences and Technologies, IARIA, Vol.9, No.1 and 2, pp.50–64, June (2017).

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