Abstract
In the past few decades, electronic controls have replaced manual controls on many types of instrumentation, appliances, and other devices. The operation of electronic devices appears to require interaction among several cognitive domains, that is, visual, linguistic, praxic, executive, memory, and visuospatial. An obvious difference between electronic devices and conventional instruments and tools is that the former incorporate many spatially interspersed buttons, mostly of a similar shape. Thus, it is reasonable to assume that a better developed visuospatial sense is needed to use electronic button–controlled devices than to use conventional devices (i.e., the need to remember, find, and press the appropriate buttons).
Studies have examined how people with dementia or cognitive impairment cope with electronic button–controlled devices. Nygård and Starkhammar (2003) assessed the difficulties in telephone use among people with dementia by using a constant comparative method; using the same method, they studied how people with mild dementia manage to cope with familiar technologies such as computers (Nygård & Starkhammar, 2007). Rosenberg, Nygård, and Kottorp (2009) used the Everyday Technology Use Questionnaire to evaluate the ability of older adults with and without cognitive impairment or dementia to competently use technology. Hällgren, Nygård, and Kottorp (2011) used the same questionnaire to test the ability of participants with intellectual disabilities to use technological artifacts and services in their everyday life. Engström, Lexell, and Lund (2010) found that participants with brain injuries had difficulties using everyday technology by qualitatively analyzing the results of a questionnaire given to the participants and using a constant comparative method. Malinowsky, Almkvist, Nygård, and Kottorp (2012) assessed the ability of older adults to manage everyday technology using an observed performance assessment with a three-category rating scale.
In short, the ability to use modern electronic devices has been investigated using a constant comparative method, questionnaires, and an observed performance assessment, but none of the earlier studies incorporated only one type of device. Moreover, previous studies of the use of electronic devices did not address a specific cognitive domain. The studies described here prompted us to investigate a specific cognitive domain, that is, visuospatial deficits, using a single device to control for biases that may have been present in those studies.
In 1909, the German neurologist Bálint described a striking set of visuospatial defects that manifested after multiple cerebrovascular lesions, mainly in the bilateral parietal lobes (Bálint, 1909). This set of defects came to be known as Bálint syndrome. People with Bálint syndrome (Bálint, 1909) display all the hallmarks of visuospatial deficits, which are categorized into three physical symptoms: psychic paralysis of gaze, spatial disorder of attention, and optic ataxia. Psychic paralysis of gaze is the inability to voluntarily shift one’s gaze to objects of interest despite unrestricted ocular movement. Spatial disorder of attention is also known as dorsal simultaneous agnosia (Luria, 1959; Rizzo & Vecera, 2002) and is the inability to perceive several items in a visual scene at one time. Optic ataxia is difficulty in reaching for an object correctly under visual guidance despite normal limb strength. In daily life, people with Bálint syndrome have difficulties finding objects, remembering the locations of objects, and correctly estimating the spatial relations between objects.
Given the substantial effect on movement associated with Bálint syndrome, most affected people would be expected to have difficulty manipulating button-controlled electronic devices. Although people with Bálint syndrome were first described more than a century ago, little is known about whether they are able to effectively use such devices. Our hypothesis, which formed the basis of this study, was that study participants with Bálint syndrome would be unable to use electronic devices that are operated with many spatially interspersed buttons. Accordingly, we designed the study to assess the ability of people with Bálint syndrome to use common button-operated electronic devices with different design features by comparing their ability with that of two control groups: (1) people with amnesia and (2) healthy control participants. We placed special emphasis on people with a mild form of Bálint syndrome, that is, those who routinely use nonelectronic household utensils and tools.
Method
To operate electronic devices, people need several types of cognitive function: visual, linguistic, praxic, executive, memory, and visuospatial. To enable a study to focus specifically on visuospatial function, tasks should take a small amount of time and be easy to understand and accomplish. A simple button-pressing task on an electronic device should be suitable for such a purpose because it requires a limited amount of cognitive function.
For this study, we recruited two control groups, one composed of healthy participants and the other composed of people with cognitive dysfunction (i.e., amnesia). The amnesia group was included because we wanted to compare visuospatial function with a second, unrelated cognitive function. Participants with amnesia were expected to be able to complete the button-pressing task because their visual, linguistic, praxic, and visuospatial functions are not impaired, and the task requires a limited amount of memory function.
Participants
Ethics-related aspects of this study were reviewed and approved by the Edogawa Hospital Human Research Ethics Committee. Seven outpatients with Bálint syndrome were recruited from the Department of Rehabilitation at Edogawa Hospital (n = 4) and the Cognitive Function Clinic at Ashikaga Red Cross Hospital (n = 3). The etiology of Bálint syndrome was cerebrovascular disease in 6 participants and traumatic brain injury in 1 participant. They had no neurological or psychiatric disorders before their brain damage. All study participants were medically stable and had passed the acute and subacute stages of brain damage within a few months and were at least 1 yr postonset of Bálint syndrome.
When participants were deemed medically stable, they had at least two of the following three symptoms: psychic paralysis of gaze, spatial disorder of attention, and optic ataxia. Three participants (Participants 1–3) initially had all three symptoms when they became medically stable approximately 3 mo after brain damage. Participant 1 still had all three symptoms at the time of examination, whereas the psychic paralysis of gaze of Participants 2 and 3 had gradually resolved within 1 yr, and they had only two of the three symptoms (spatial disorder of attention and optic ataxia) at the time of examination. These 3 participants were defined as having severe Bálint syndrome.
Participants 4–7, defined as having mild Bálint syndrome, had only two of the three symptoms after brain damage and when they were medically stable approximately 3 mo after brain damage. All 4 participants initially had spatial disorder of attention and optic ataxia, although their symptoms had improved within 1 yr such that they had only spatial disorder of attention at the time of examination. Spatial disorder of attention is considered the hallmark of Bálint syndrome (Rizzo & Vecera, 2002) and was present in all 7 participants. Detailed descriptions of 1 participant with severe Bálint syndrome and 1 participant with mild Bálint syndrome are provided in the Appendix. People with severe Bálint syndrome are usually unable to do household tasks, and those with mild Bálint syndrome are usually able to use ordinary household utensils and tools and can carry out most routine household chores.
For the amnesia control group, 8 participants with memory deficits were recruited from the Edogawa Hospital (n = 4) and the Ashikaga Red Cross Hospital (n = 4), forming the amnesia control group. The etiology of the memory deficits was limbic encephalitis (3 participants), traumatic brain damage (3 participants), and cerebrovascular disease (2 participants). Eight healthy participants without brain injury, each of whom was recruited from Edogawa Hospital, formed the healthy control group.
All participants were right-handed and native Japanese with ≥12 yr of education and met the following seven inclusion criteria: (1) ≥2 mo since onset of brain damage; (2) known to live almost independently at home and able to perform activities of daily living, including toileting and feeding; (3) achieved the maximum score on the Barthel Index (Mahoney & Barthel, 1965); (4) had a verbal intelligence quotient (VIQ) ≥55 on the Japanese version of the Wechsler Adult Intelligence Scale (WAIS; Fujita, 2006) and were able to understand and follow task instructions; (5) had no ocular or upper-limb palsy; (6) had normal visual acuity by daily observation; and (7) had sufficient motor ability to perform the trial tasks and not be limited by apraxia. Participants 1 and 3 had mild apraxia that was not severe enough to limit task performance. The study took place in the outpatient clinics associated with the Edogawa Hospital and Ashikaga Red Cross Hospital.
Demographic Features and Basic Neuropsychological Assessments
The demographic features investigated were age, gender, level of education, and years postonset. The Bálint syndrome group and the amnesia control group completed a battery of standardized neuropsychological tests. General cognitive function was evaluated using the Japanese version of the Mini-Mental State Examination (MMSE–J; Sugishita & Hemmi, 2010) and the revised version of Hasegawa's Dementia Scale (HDS–R; Katoh et al., 1991), which is similar to the MMSE and is widely used in Japan. The HDS–R includes items that assess orientation, memory, repetition, backward digit span, calculation, and category fluency. VIQ and performance intelligence quotient (PIQ) were evaluated using the Japanese version of the WAIS (Fujita, 2006).
Visuospatial ability was evaluated using the Japanese versions of the Trail Making Test A and B (Trails A and B; Kashima, Handa, & Katoh, 1986), which were originally designed to evaluate visual attention (Trails A) and switching ability (Trails B). Performance on Trails A and B is expected to be severely impaired in people with Bálint syndrome because of their visuospatial deficits. The time limit for each section was 600 s. If the participant had not completed a section in this time, the trial was terminated and a value of 600 s was used for statistical analysis. These neuropsychological tests have been demonstrated to have content validity and reliability (MMSE–J, Sugishita & Hemmi, 2010; HDS–R, Katoh et al., 1991; WAIS, Fujita, 2006; Trails A and B, Kodama & Asada, 2008).
Neuroanatomical Analysis
Images of overlapped lesions of the most recent clinical structural scans were generated using MRIcro software (McCausland Center for Brain Imaging, Columbia, SC). This method is essentially a direct-to-digital variant of template-based spatial normalization that has been the standard approach in group lesion studies and remains the gold standard for delineation of chronic brain lesions with intraclass correlation coefficients of .86–.95 (Wilke, de Haan, Juenger, & Karnath, 2011).
A speech therapist (Yoshitaka Nakagawa) who had 3 yr experience with this method at the time of the study performed the analysis without knowing how the participants performed on the button-pressing task and the neuropsychological assessments. Individual lesions were traced from the most recent clinical MRIs. The method to transpose lesions was as follows. All major sulci in the lesions were identified via clinical MRI. Each lesion boundary was identified and manually transferred onto the template brain taking into account the relation of the lesion boundary to the identified sulci. After transferring all lesion images, the regions of interest were overlapped to explore their mutual involvement on a voxel-by-voxel basis using the MRIcro regions of interest menu commands.
Button-Pressing Tasks
Electronic devices assign functions to buttons; therefore, the ability to use electronic devices was tested using three button-pressing tasks, with Arabic numerals assigned to the buttons. Unlike Indo-European languages, the Japanese language uses three different writing systems, each of which has at least 46 characters. Therefore, compared with those systems, Arabic numerals, which are also commonly used in Japan, are easier to handle.
Participants were instructed to input a digit sequence of 1–11 digits (e.g., 2, 35, 625, 4983, 59184, 918243 . . . 38749120564) into each of three electronic devices: a smartphone (Docomo P-02D; device size, 123 × 64 × 10.2 mm; button size, 10 × 11 mm; NTT Docomo, Tokyo), a flip phone (Docomo F-02A; device size, 108 × 49 × 16.4 mm when unfolded; button size, 10 × 6 mm), and an electronic calculator (Casio JS-250WN; device size, 112 × 83 × 8 mm; button size, 9 × 11 mm; Casio Computer Corporation, Tokyo). The smartphone had a flat touch screen, and the flip phone and electronic calculator had buttons that protruded from the surface. The buttons of the electronic calculator were sky blue against a deep blue background, and both the buttons and background of the flip phone were dark blue. The three different devices were used in case the shape or color of a device and its buttons affected task performance.
Two patterns of digit sequences were tested: one that used any of 10 digits (0–9; normal pattern) and a second that used only 7 digits (0, 2, 3, 5, 6, 8, 9) in a without-left pattern; that is, it used those digits associated with buttons that lay in the center or the right side of each device. This pattern was designed to eliminate the potential impact of left-sided spatial neglect. The digit sequences were random and new each time.
First, a single digit of the normal pattern was tested using the smartphone, followed by a without-left pattern single digit using the smartphone. Then, a sequence of two normal-pattern digits was performed using the same device, followed by a sequence of two without-left digits. The digit sequences were presented in ascending order, that is, from a single digit to a sequence of 11 individual digits, resulting in 22 unique sequences being tested using the smartphone. After completing all 22 smartphone trials, each participant moved on to the flip phone using the same digit sequences as for the smartphone and then to the electronic calculator using the same digit sequences, with a 1-min break between each device. For all three devices, each participant entered 66 unique sequences in total.
Each digit sequence was printed in 16-point MS Gothic font in black ink on a piece of white A4-sized paper that was placed on a table in front of each participant, who was seated. The paper remained in place until the participant finished entering the digits into the device. Each participant was instructed to input the digit sequence into one of the three electronic devices.
Performance was recorded with a digital video camera (Sony Handycam CX630V; Sony Corporation, Tokyo) and quantified as the time taken to input the numbers into the device. The timer was started when the examiner instructed the examinee to start each task. The time limit for each digit sequence was 45 s. If the participant had not input all the numbers in the digit sequence within this time, the trial was terminated, and a value of 45 s was used for statistical analysis.
Statistical Analysis
Two analyses were performed: (1) a comparison of the Bálint syndrome group (n = 7), the amnesia control group (n = 8), and the healthy control group (n = 8) and (2) a comparison of the performances of the mild Bálint syndrome group (n = 4), the amnesia control group (n = 8), and the healthy control group (n = 8).
Age and education had unequal variance and were compared across the three groups using the Kruskal–Wallis test. Gender distribution was compared across the three groups using Fisher’s exact test. Neuropsychological data (MMSE–J score, HDS–R score, VIQ, PIQ, Trails A and B scores) and years postonset were nonparametric and compared across the Bálint syndrome group and the amnesia control group using the Mann–Whitney U test. For each device and each digit-sequence length, the time taken to input the normal-pattern digit sequence was compared across the three groups using the Kruskal–Wallis test. Post hoc pairwise comparisons were made using the Steel–Dwass test.
The time taken to input the digit sequence was compared with the normal and without-left patterns using the Mann–Whitney U test for each group. This comparison was performed separately for each device and each digit-sequence length.
For each group, the time taken to input a digit sequence was compared across the three devices using the Kruskal–Wallis test followed by the Steel–Dwass test. This comparison was performed only for the normal-pattern sequences and was performed separately for each sequence length. Excel 2010 (Microsoft Corporation, Redmond, WA) with add-in Statcel 3 software (OMS Ltd., Tokyo) was used for all statistical analyses. Significance was set at p < .05, two tailed.
Results
Demographic Features and Neuropsychological Data
Table 1 shows the demographic characteristics (age, gender, education level, and years postonset) and neuropsychological test scores for each of the 7 participants with Bálint syndrome and the average for each control group. The Bálint syndrome group and the two control groups did not differ with respect to age (Kruskal–Wallis test, p = .32), education (Kruskal–Wallis test, p = .34), or gender distribution (Fisher’s exact test, p = .67). The MMSE–J score (Mann–Whitney U test, p = .22), HDS–R score (Mann–Whitney U test, p = .33), VIQ (Mann–Whitney U test, p = .56), and years postonset (Mann–Whitney U test, p = .24) were similar for the Bálint syndrome group and the amnesia control group, but the scores on the three tests that involve visuospatial function were lower for the Bálint syndrome group than for the amnesia group (Mann–Whitney U test, p = .01, p < .01, and p = .03, for the PIQ, Trails A and B, respectively). Of the participants with Bálint syndrome, 4 did not finish Trails A within the 600-s limit, and 5 did not finish Trails B within the 600-s limit.
Demographic Features and Neuropsychological Data
Note. Maximum time on the TMT–A and the TMT–B is 600 s; participants not finishing after 600 s are indicated with DNF. — = not applicable; DNF = did not finish; F = female; M = male; HDS–R = the revised version of Hasegawa's Dementia Scale; MMSE–J = Japanese version of the Mini-Mental State Examination; NA = not assessed; PIQ = performance intelligence quotient; TMT–A = Trail Making Test A; TMT–B = Trail Making Test B; VIQ = verbal intelligence quotient.
Cutoff = 23. bCutoff = 20. cNormal range = 70–130. dAverage for 60 s = 157.6. eAverage for 60 s = 216.2. fRange = 1–10.
When the 3 participants with severe Bálint syndrome were excluded, the remaining 4 participants with mild Bálint syndrome and the two control groups still had similar distributions of age (Kruskal–Wallis test, p = .32), education (Kruskal–Wallis test, p = .34), and gender (Fisher’s exact test, p = .60), and the mild Bálint syndrome group and the amnesia control group had similar MMSE–J scores (Mann–Whitney U test, p = .67), HDS–R scores (Mann–Whitney U test, p = .93), VIQ (Mann–Whitney U test, p > .99), and years postonset (Mann–Whitney U test, p = .35). The mild Bálint syndrome group had lower scores than did the amnesia group on Trails A (Mann–Whitney U test, p < .01); the PIQ (Mann–Whitney U test, p = .08) and Trails B (Mann–Whitney U test, p = .09) scores trended lower for the mild Bálint syndrome group, although the difference was not statistically significant.
Neuroanatomical Analysis
Figure 1 shows the image of the overlapped lesions of the 7 participants with Bálint syndrome. Five participants had bilateral parietal or occipital lesions as shown by their MRIs, and 1 participant had a unilateral right parieto-occipital lesion as shown by MRI. One participant with a watershed infarction caused by hypotension did not present with any lesions on MRI or computed tomography, but single-photon emission computed tomography demonstrated a remarkable bilateral hypoperfusion in the parieto-occipital lobe. The extent of overlap of the lesions in our participants is comparable with those reported previously (Bálint, 1909; Rizzo & Vecera, 2002).
Overlapped lesion images for the 7 participants with Bálint syndrome.
Smartphone Button-Pressing Task
Figure 2(A) shows the mean time taken to input each digit sequence into the smartphone for all four experimental groups. The time taken differed across the combined Bálint syndrome group, the amnesia control group, and the healthy control group for digit sequences of all lengths (Kruskal–Wallis test, all ps < .01). Post hoc comparisons showed that the combined Bálint syndrome group took longer than did the amnesia group (Steel–Dwass test, all ps < .05) and the healthy control group (Steel–Dwass test, all ps < .01) for digit sequences of all lengths. Conversely, the two control groups took a similar amount of time (Steel–Dwass test, all ps > .10).
Time to input a digit sequence on the 3 devices: (A) smartphone; (B) flip phone; (C) electronic calculator.
The aforementioned results were similar to those that excluded the participants with severe Bálint syndrome. The time taken differed across the mild Bálint syndrome group, the amnesia control group, and the healthy control group for digit sequences of all lengths (Kruskal–Wallis test, all ps < .05). Post hoc comparisons showed that the mild Bálint syndrome group took longer to input sequences of two to eight digits than did the amnesia control group (Steel–Dwass test, all ps < .05) and took longer than did the healthy control group for digit sequences of all lengths (Steel–Dwass test, all ps < .05).
Flip Phone Button-Pressing Task
Figure 2(B) shows the mean time taken to input each digit sequence into the flip phone for all four experimental groups. The time taken to input a digit sequence into the flip phone differed across the three groups for digit sequences of all lengths (Kruskal–Wallis test, all ps < .01). Post hoc comparisons showed that the combined Bálint syndrome group took longer to input sequences of all lengths than did the amnesia control group (Steel–Dwass test, all ps < .05) and the healthy control group (Steel–Dwass test, all ps < .01), but the amnesia and healthy control groups took a similar amount of time (Steel–Dwass test, all ps > .10).
The results were similar when the participants with severe Bálint syndrome were excluded. The time taken differed across the mild Bálint syndrome group, the amnesia control group, and the healthy control group for sequences of all lengths (Kruskal–Wallis test, all ps < .05). Post hoc comparisons showed that the mild Bálint syndrome group took longer than did the amnesia control group for 2-, 3-, and 4- to 10-digit sequences (Steel–Dwass test, all ps < .05) and took longer than did the healthy control group for digit sequences of all lengths (Steel–Dwass test, all ps < .05).
Electronic Calculator Button-Pressing Task
Figure 2(C) shows the mean time taken to input each digit sequence into the electronic calculator for all four experimental groups. The time taken to input a digit sequence into the electronic calculator differed between the combined Bálint syndrome group and each of the control groups for sequences of two or more digits (Kruskal–Wallis test, all ps < .05). Post hoc comparisons showed that the combined Bálint syndrome group took longer than the amnesia control and healthy control groups (Steel–Dwass test, all ps < .05) for digit sequences of all lengths, but the two control groups took a similar amount of time (Steel–Dwass test, all ps > .10).
The results were similar when the participants with severe Bálint syndrome were excluded. The time taken differed for the mild Bálint syndrome group and the two control groups for digit sequences of all lengths except 2-digit sequences (Kruskal–Wallis test, all ps < .05). Post hoc comparisons showed that the mild Bálint syndrome group took longer than did the two control groups for sequences of 3–11 digits (Steel–Dwass test, p < .05 for all). Notably, 2 of 3 participants with severe Bálint syndrome were able to input sequences of 1–5 digits.
Investigation of Left-Sided Hemineglect
For digit sequences of all lengths and for all three devices, the time taken to input a digit sequence did not differ with respect to which pattern of digit sequences was tested, that is, the normal pattern versus the without-left pattern (Mann–Whitney U test, p > .50 for the combined Bálint syndrome group, p > .40 for the amnesia control group, and p > .50 for the healthy control group).
Effect of the Device on the Results
The time taken to input a digit sequence was similar for all three devices and for all sequences (Kruskal–Wallis test, all ps > .40 for the combined Bálint syndrome group, all ps > .10 for the two control groups). For each sequence of one to five digits, the averaged times of the participants with severe Bálint syndrome for the electronic calculator were not statistically different than those for the other devices (Mann–Whitney U test, p > .1), which may be a consequence of the small number of participants.
Clinical Observations
Notable qualitative characteristics were associated with our Bálint syndrome participants. Those with severe Bálint syndrome could not input a one-digit number into any device within the 45-s limit. They sometimes could not find the designated number on the device or could not guide their hand toward the number, which sometimes resulted in them pressing another number. Participants with mild Bálint syndrome had difficulty perceiving both the paper and the device at the same time. Moreover, participants with mild Bálint syndrome usually could not memorize more than four digits, and they often forgot how many digits they had input, sometimes omitting digits or changing the order of digits.
Discussion
Our study yielded two key findings. First, participants with Bálint syndrome have difficulty inputting numbers into an electronic device. This was not simply a result of left-sided neglect, because the poor performance remained when a digit sequence did not include any numbers on the left side of a display and did not depend on the type of electronic device; rather it was a consequence of poor button operation. Second, even participants defined as having mild Bálint syndrome (because they can use ordinary household utensils and tools) performed poorly compared with the two control groups.
Button pressing is needed for operation of modern electronic devices, including smartphones, personal computers, bank automated teller machines, and ticket-vending machines. Generally, conventional tools have only one function, and one can readily determine how to operate a tool on the basis of its shape or by watching someone else use it. Electronic devices, however, usually have a wide variety of functions that are operated by buttons without distinctive features except for the symbols and numbers displayed on, above, and below the buttons. Our findings suggest that the visuospatial disorder that is characteristic of people with Bálint syndrome disrupts their ability to use electronic devices. Even our participants with mild Bálint syndrome who could perform ordinary housework tasks found button operation difficult.
Recently, Nygård and Starkhammar (2007) reported that people with dementia have difficulty using electronic devices and suggested that visuospatial deficits may underlie some of these difficulties (e.g., an inability to turn handles and switches in the appropriate direction and to coordinate more than one piece of technological equipment). The focus and the questions asked in that study, however, differed from ours. To our knowledge, no reports have examined button operation by people with visuospatial deficits.
Our observations concerning task performance indicated that the severity of Bálint syndrome influences the ability to press a button on an electronic device. The clinical difference between severe and mild Bálint syndrome lies in the presence of psychic paralysis of gaze, optic ataxia, or both. Psychic paralysis of gaze would result in an inability to find the required number on the electrical device and optic ataxia in an inability to guide the hand toward the required number. It is therefore reasonable that button-pressing performance was worse for the participants with severe Bálint syndrome than for the participants with mild Bálint syndrome.
In addition to spatial disorder of attention, our participants with mild Bálint syndrome usually could not remember more than four digits, suggestive of poor visual short-term memory. The number of digits that could be memorized, or the visual short-term memory of a participant, might also contribute to the poor performance on the button-pressing task. The difference between severe and mild Bálint syndrome is a matter of great importance to occupational therapy practitioners. Although Bálint syndrome is considered to consist of three signs (i.e., psychic paralysis of gaze, spatial disorder of attention, and optic ataxia), practitioners should identify each of the three signs separately to clarify what defects a client has.
Even though the type of device did not statistically influence the outcomes of our experiments, notably, 2 of the 3 participants with severe Bálint syndrome were able to input sequences of one to five digits when using the electronic calculator. This finding suggests that raised buttons and differences in background and foreground colors might facilitate the use of electronic devices.
Study Limitations and Future Research
Our study has several limitations that should be considered when interpreting the results. To begin, limitations resulting from the study design include that the input data were limited to Arabic numerals, which do not represent all Japanese-language characters. However, we believe that use of a Japanese writing system would have been more difficult for participants with a visuospatial deficit. Additionally, input data were presented only visually because instructions for electronic devices and telephone numbers are usually presented visually, not verbally. The use of a personal computer might have been better suited for our study; however, the participants with Bálint syndrome would have had a harder time using a personal computer because they would have had many more buttons to find and press. Last, although we tried to design the button-pressing tasks to be as simple as possible, other cognitive-domain deficits, particularly executive dysfunction, might have affected the participants’ performances. However, executive function is an umbrella term for a list of basic processes that supervise, coordinate, and control the execution of more domain-specific and basic cognitive processes and is necessary for a series of actions or dual tasks.
Conversely, the tasks used in this study can be considered to be relatively simple, and executive function involvement should have been minimal. Regarding reliability, we did not examine test–retest reliability of coherence. However, the observation that three different electronic devices produced similar results suggests that the results might be reliable. Another possible limitation is the small number of participants included in our study. However, the existing literature on Bálint syndrome consists of only case reports (Rizzo & Vecera, 2002) and, to our knowledge, this is the first study of a group of persons with Bálint syndrome.
The results of this study shed light on the relation between a visuospatial deficit and the ability to use electronic devices. The number of people with cognitive deficits, including visuospatial deficits, is increasing, and our results suggest that this might result in an increasing number of people who have difficulty manipulating electronic devices. For future research, it might be advisable to study the relationship between visuospatial deficit in degenerative diseases, for example, Alzheimer’s disease, and the ability to use electronic devices. In addition, it might be worth investigating what distinctive features would help people with cognitive deficits to operate electronic devices.
Implications for Occupational Therapy Practice
The results of this study have the following implications for occupational therapy practice:
Visuospatial deficits in persons with Bálint syndrome greatly affect button operation of electronic devices.
In the case of persons with mild Bálint syndrome, the assessment and adaptive approach is needed for their use of electronic devices in everyday life.
Distinctive design features in electronic devices might positively affect performance of persons with Bálint syndrome.