disturbances of levels of consciousness or awareness (see Table 12.1.1, Table 12.1.2 and Table 12.1.3);
impairment of memory, learning, abstract reasoning and problem solving ability (see Table 12.2);
communication (see Table 12.3.1 and Table 12.3.2); and
emotional or behavioural impairments (see Table 12.4).

WPI ratings from these four categories of cerebral impairment may not be combined with each other. The highest WPI rating from these four categories is to be used. Unless otherwise indicated, the highest WPI rating may then be combined with:

a WPI rating from any other table or tables in Chapter 12 other than tables covering the first four categories;
WPI ratings from tables in other chapters.

The following procedure should be used in assessing cerebral function.

Step 1	Determine whether disturbance is present in the level of consciousness or awareness (Table 12.1.1, Table 12.1.2 and Table 12.1.3). This may be a permanent alteration or an intermittent alteration in consciousness, awareness or arousal. Use the most applicable of Table 12.1.1, Table 12.1.2 or Table 12.1.3.
Step 2	Evaluate mental status and highest integrative functioning (Table 12.2).
Step 3	Identify any difficulty with comprehension and the use of language (Table 12.3.1 and Table 12.3.2). Use the higher of the WPI ratings from these two tables.
Step 4	Evaluate any emotional or behavioural disturbances, such as depression, that can modify cerebral function (Table 12.4).
Step 5	Identify the most severe cerebral impairment from steps 1 to 4 above. Combine the most severe WPI rating with WPI ratings from any tables in Chapter 12 including and following Table 12.5.1, or with WPI ratings from other chapters.

'Activities of Daily Living' are those that an employee needs to perform to function in a non-specific environment (that is, to live). Performance of Activities of Daily Living is measured by reference to primary biological and psychosocial function.

For the purposes of Chapter 12, Activities of Daily Living are those in Figure 12-A.

Figure 12-A: Activities of Daily Living

Activity	Examples
Self care, personal hygiene.	Bathing, grooming, dressing, eating, eliminating.
Communication.	Hearing, speaking, reading, writing, using keyboard.
Physical activity.	Standing, sitting, reclining, walking, stooping, squatting, kneeling, reaching, bending, twisting, leaning, carrying, lifting, pulling, pushing, climbing, exercising.
Sensory function.	Tactile feeling.
Hand functions.	Grasping, holding, pinching, percussive movements, sensory discrimination.
Travel.	Driving or travelling as a passenger.
Sexual function.	Participating in desired sexual activity.
Sleep.	Having a restful sleep pattern.
Social and recreational.	Participating in individual or group activities, sports activities, hobbies.

Notes Regarding Station, Gait and Movement Disorders

Station, gait and movement disorders:

station and gait disorders affecting the lower extremities are to be assessed under Table 9.7: Lower Extremity Function (Chapter 9 - Musculoskeletal System);

movement disorders affecting the upper extremities are to be assessed under Table 9.14 Upper Extremity Function (Chapter 9 - Musculoskeletal System);

except as provided for in the case of injury involving spinal cord damage, (see notes to Tables 9.15 - 9.17, Chapter 9 - Musculoskeletal System), station, gait and movement disorders may not be combined with any other WPI ratings from Chapter 9 for the same condition, but may be combined with other WPI ratings under Chapter 12.

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12.1 Disturbances of Levels of Consciousness and Awareness

12.1.1 Permanent Disturbances of Levels of Consciousness and Awareness

Table 12.1.1 applies to stupor, coma, and permanent vegetative state. These conditions are assessed based on clinical findings on neurological examination and relevant ancillary testing such as CT scan, MRI, SPECT, EEG, evoked potentials and vestibular testing.

Table 12.1.1: Permanent Disturbances of Levels of Consciousness and Awareness

% WPI	Criteria
15	Mild persistent alteration of state of consciousness limiting ability to perform some activities requiring alertness but not interfering with self care.
30	Moderate persistent alteration of state of consciousness limiting ability to perform most Activities of Daily Living including self care.
70	Semi-comatose state with complete dependence on others for self care and subsistence.
95	Persistent vegetative state or coma requiring total medical support in a specialised care facility.

12.1.2 Epilepsy, Seizures and Convulsive Disorders

Table 12.1.2 is used for episodic neurological disorders of consciousness and awareness.

Table 12.1.2: Epilepsy, Seizures and Convulsive Disorders

% WPI	Criteria
10	Paroxysmal disorder with predictable characteristics but unpredictable occurrence; and Frequency and severity of attacks places some restrictions on Activities of Daily Living and may constitute a risk to the employee.
20	Paroxysmal disorder with predictable characteristics but unpredictable occurrence; and Frequency and severity of attacks places many restrictions on Activities of Daily Living and constitutes a risk to the employee.
40	Severe paroxysmal disorder of such frequency and severity that it limits Activities of Daily Living to those that are supervised or protected.
70	Severe, uncontrollable paroxysmal disorder of such severity that it totally restricts the employee's daily activities - full time care and supervision required.

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12.1.3 Sleep and Arousal Disorders

Arousal and sleep disorders include disorders related to:

initiating and maintaining sleep, or inability to sleep;
excessive somnolence, including sleep-induced respiratory impairment; and
sleep-wake schedules.

Central sleep apnoea should be assessed using Table 12.1.3 below. Obstructive sleep apnoea should be assessed using Table 2.4: Whole Person Impairment Derived from Obstructive Sleep Apnoea Score (Chapter 2 - The Respiratory System).

Table 12.1.3: Sleep and Arousal Disorders

% WPI	Criteria
10	Reduced daytime alertness placing some restrictions on Activities of Daily Living, performance of which might constitute a risk to the employee.
20	Reduced daytime alertness placing many restrictions on Activities of Daily Living and constituting a risk to the employee.
40	Reduced daytime alertness of such severity that it limits Activities of Daily Living to those that are supervised or protected.
60	Severe reduction in daytime alertness which totally restricts the employee's daily activities. Full time care and supervision required.

Notes to Table 12.1.3

1. Supervision means the immediate presence of a suitable person, responsible in whole or in part for the care of the employee

2. Suitable person means a person capable of responsibly caring for the employee in an appropriate way

12.2 Impairment of Memory, Learning, Abstract Reasoning and Problem Solving Ability

WPI ratings in Table 12.2 reflect increasing levels of severity. To satisfy particular WPI rating requirements, the majority of criteria for each WPI rating should be present, as described in Figure 12-B.

The WPI ratings are incremental. In order to satisfy the criteria for a particular degree of impairment, the employee must have a greater degree of impairment than that described for the preceding levels.

The Clinical Dementia Rating (CDR) test for memory, abstract reasoning and problem solving (Figure 12-B) should be administered by a professional competent in the area.

The employee's cognitive function for each category (Memory, Orientation, Judgement and Problem Solving, Community Affairs, Home and Hobbies, Personal Care) is scored independently. For the purposes of assessing impairment, Memory is considered the primary category. The other categories are secondary.

The following rules apply to scoring:

if at least three secondary categories are given the same numeric score as Memory, then the Clinical Dementia Rating equals the Memory score (CDR=M);

if three or more of the secondary categories are given a score greater than or less than that for Memory, then CDR is increased or decreased from M by one level as applicable;

however, if three secondary categories are scored one side of M, and two are scored on the other side of M, then CDR=M.

Find the row in Table 12.2 that exactly matches the respective scores for CDR and Memory. The WPI rating is shown in the first column of that row.

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Table 12.2: Impairment of Memory, Learning, Abstract Reasoning and Problem Solving Ability

% WPI	CDR Score	Memory Score
0	0	0
3	0.5	0
7	0.5	0.5
10	0.5	1.0
15	1.0	0.5
20	1.0	1.0
25	1.0	2.0
30	2.0	1.0
40	2.0	2.0
45	2.0	3.0
55	3.0	2.0
70	3.0	3.0

Figure 12-B: Clinical Dementia Rating (CDR)

From American Medical Association's Guides to the Evaluation of Permanent Impairment (5^th edition, 2001).

	Impairment Level and CDR Score (most of the criteria for a particular WPI rating should be present)
Category	None 0	Questionable 0.5	Mild 1.0	Moderate 2.0	Severe 3.0
Memory (M)	No memory loss, or slight inconsistent forgetfulness.	Consistent slight forgetfulness; partial recollection of events; 'benign' forgetfulness.	Moderate memory loss; more marked for recent events; defect interferes with everyday activities.	Severe memory loss; only highly learned material retained; new material rapidly lost.	Severe memory loss; only fragments remain.
Orientation (O)	Fully oriented.	Fully oriented, except for slight difficulty with time relationships	Moderate difficulty with time relationships; oriented for place at examination; may have geographic disorientation elsewhere.	Severe difficulty with time relationships; usually disoriented to time, often to place.	Oriented to person only.
Judgement and Problem Solving (JPS)	Solves everyday problems and handles business and financial affairs well; judgement good in relation to past performance.	Slight impairment in solving problems, similarities and differences.	Moderate difficulty in handling problems, similarities and differences; social judgement usually maintained.	Severely impaired in handling problems, similarities and differences; social judgement usually impaired.	Unable to make judgements or solve problems.
Community Affairs (CA)	Independent function at usual level in job, shopping, volunteer and social groups.	Slight impairment in these activities.	Unable to function independently at these activities although may still be engaged in some; appears normal to casual inspection.	No pretence of independent function outside home; appears well enough to be taken to functions outside a family home.	No pretence of independent function outside home; appears too ill to be taken to functions outside a family home.
Home and Hobbies (HH)	Life at home, hobbies and intellectual interests well maintained.	Life at home, hobbies and intellectual interests slightly impaired.	Mild but definite impairment of function at home; more difficult chores abandoned; more complicated hobbies and interests abandoned.	Only simple chores preserved; very restricted interests, poorly maintained.	No significant function in home.
Personal Care (PC)	Fully capable of self care.	Fully capable of self care.	Needs prompting.	Requires assistance in dressing, hygiene, keeping of personal effects.	Requires much help with personal care; frequent incontinence.

Source: Morris JC, 1993,'The Clinical Dementia Rating (CDR): current version and scoring rules', Neurology, 43(11): 2412-2414.

12.3 Communication

Before proceeding to test the employee's mental status and cognitive functioning, the assessor should first determine whether there is impairment of comprehension and/or production of speech and language symbols. If there is no such impairment, tests of memory and abstract reasoning may be performed and a WPI rating identified on the basis of the results obtained.

If there is a communication impairment, this should be assessed first, then the tests of cognitive functioning may be administered if the level of communication impairment permits.

A WPI rating from Table 12.3.1: Comprehension of Speech and Language Symbols may not be combined with a WPI rating from Table 12.3.2: Production of Speech and Language Symbols. The greater of the two values is used as the WPI rating.

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12.3.1 Comprehension of Speech and Language Symbols

Language symbols include those produced by voice, action, mime or writing.

In all cases the level of premorbid comprehension should be considered as the baseline. It is inappropriate to assess an illiterate employee with respect to reading skills. Where English is the second language, assessment should be based on comprehension of the first language. A qualified interpreter should be used to assist in this.

The WPI ratings in Table 12.3.1 reflect increasing levels of severity. It is not necessary to satisfy all the criteria at a given level to award that WPI rating. However, to satisfy the requirements for a particular WPI rating, the majority of the elements described should be present.

The WPI ratings are incremental. To satisfy the criteria for a particular WPI rating the employee must have a greater degree of impairment than that described for the preceding levels.

WPI ratings for understanding and reading may be combined using the Combined Values Chart (Appendix 1).

Table 12.3.1 is not used to evaluate difficulties with speech comprehension due to hearing loss. If hearing loss is the prime impairment, the assessment should be conducted under Chapter 7 - Ear, Nose and Throat Disorders.

A WPI rating from Table 12.3.1 may not be combined with a WPI rating from Table 12.3.2: Production of Speech and Language Symbols. The higher of the WPI ratings from Table 12.3.1 and Table 12.3.2 is used.

Table 12.3.1: Comprehension of Speech and Language Symbols

% WPI	Understanding	Reading
0	Normal comprehension of speech and language symbols; or Can follow group discussions and rapid changes of topic and understand complex instructions.	Can read and understand at premorbid levels.
8	Speech comprehension is good in most situations but there are difficulties in group situations or when the employee is tired or upset; or Has difficulty coping with rapid changes of topic but otherwise understands films, plays and radio programmes.	Difficulty with complex ideas and plots and some technical material.
15	At least TWO of the following: Can understand speech in a one-to-one situation but unable to cope with more than one speaker eg: in group situations; Unable to cope with rapid changes of topic; Unable to understand more complex films, plays and radio and TV programs but able to follow simple programs (for example, cartoons, soap opera and variety shows).	Unable to follow the plot in most books but can understand simple magazines and newspaper articles.
25	At least TWO of the following: Can understand only simple sentences and grasp simple concepts expressed as gestures or mime; Some repetition may be necessary; Unable to follow simple radio or TV programs.	Unable to comprehend simple newspaper and magazine articles. Can cope with short sentences and simple written instructions.
40	Can understand only single words and basic gestures; or Unable to follow sentences even with repetition.	Able to read single words but unable to understand simple written instructions.
60	Unable to understand any speech or language symbols, including gestures and mime.	No functional reading.

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12.3.2 Production of Speech and Language Symbols

Language symbols include those produced by voice, action, mime or writing. In all cases, the level of premorbid oral and written expression should be considered as the baseline. It is inappropriate to assess an illiterate employee with respect to writing skills. Where English is the second language, assessment should be based on expression in the first language. Writing should be compared with ability prior to the compensable event.

The WPI ratings in Table 12.3.2 reflect increasing levels of severity. It is not necessary to satisfy all criteria at a given level to achieve that WPI rating. However, to satisfy the requirements for a particular WPI rating, the majority of elements described should be present. The WPI ratings are incremental. Therefore, to satisfy the criteria for a particular WPI rating, the employee must have a greater degree of impairment than that described for the preceding levels.

Table 12.3.2 below is not used for speech impairments arising from intrinsic disease of the larynx and other parts of the upper acrodigestive tract, nor writing difficulties due to musculoskeletal disorders affecting the dominant upper limb.

WPI ratings for speech and writing may be combined using the Combined Values Chart (see Appendix 1).

A WPI rating from Table 12.3.2 may not be combined with a WPI rating from Table 12.3.1: Comprehension of Speech and Language Symbols. The higher of the WPI ratings from these two tables is to be used.

A WPI rating under Table 12.3.2 may not be combined with a WPI rating for the same condition from Table 7.4: Speech (Chapter 7 - Ear, Nose and Throat Disorders). Where there are two separate conditions (one local, and the other a central nervous system condition) interfering with speech production, speech production should be evaluated under both Table 7.4 and Table 12.3.2. The greater value assessed is used as the impairment value due to speech impairment from all causes. The resulting WPI rating is then applied according to the procedure explained in the Introduction to Chapter 12 (see Steps 1 to 5).

Table 12.3.2: Production of Speech and Language Symbols

% WPI	Speech	Writing
0	Normal production of speech and language symbols.	Normal production of speech and language symbols.
5	Speech is sufficient for everyday needs although there may be a need for some repetition to be understood; and Some hesitancy and word retrieval problems particularly when the employee is tired or upset.	Writing sufficient for everyday needs but there is difficulty with sustained complex writing (for example, letters of more than one page).
20	Speech is limited to simple sentences and familiar topics; and Frequent hesitancy and word retrieval problems; and Difficulty explaining complex ideas.	Writing limited to half a page or less where only simple ideas need to be expressed (for example, postcards or short letters - spelling and grammatical errors evident).
30	Speech is functional only with family and close friends; and Strangers have difficulty understanding speech; and Frequent repetition and/or gestures needed.	Writing limited to familiar words or groups of words (eg, name, address shopping list); and Spelling errors frequent.
50	Speech limited to single words and/or basic gestures and able to use a picture board to express needs.	Able to write single letters but no intelligible words. May be able to write own name with practice.
60	Unable to produce any useful speech - may use inappropriate and unintelligible speech including gestures and mime.	Unable to write any meaningful symbols. No functional writing.

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12.4 Emotional or Behavioural Impairments

Emotional or behavioural disorders resulting from verifiable neurological impairments (for example, stroke or head injury) are assessed under Table 12.4 below.

Psychiatric impairments without documented neurological origin are assessed under Chapter 5 - Psychiatric Conditions. They are not assessed under Table 12.4.

Neurological conditions associated with changes in emotion and affect include:

Right hemisphere infarct and inappropriate jocularity;
Left hemisphere infarct and deep dejection, and dysphasia;
Left-sided temporolimbic seizure foci and ideational disorders;
Right-sided temporolimbic seizure foci and mood disturbances.

The Neuropsychiatric Inventory (NPI) may be used to assess 'no cognitive' behavioural symptoms such as apathy, delusions, dysphoria, agitation/aggression, euphoria, hallucinations, irritability/lability, and aberrant motor behaviour (Cummings et al, 1994).

Table 12.4: Emotional or Behavioural Impairments

% WPI	Criteria (ALL required)
0	No limitation of Activities of Daily Living and daily social and interpersonal functioning.
5	Minor limitation of Activities of Daily Living and daily social and interpersonal functioning attributable to the normal variation in the general population.
10	Mild limitation of Activities of Daily Living and daily social and interpersonal functioning. Impairment levels are compatible with most useful functioning. Able to live independently, looks after self adequately, with occasional lapses in grooming and observing nutritional requirements. Existing relationships strained.
30	Moderate limitation of some Activities of Daily Living and some daily social and interpersonal functioning. Cannot live independently without regular support. Needs supervision and/or prompting to perform activities of self-care and personal hygiene. Previously established relationships severely strained.
50	Severe limitation in performing most Activities of Daily Living. Impairment significantly impedes useful functioning in most daily social and interpersonal functioning
65	Severe limitation in performing most Activities of Daily Living. Impairment significantly impedes useful functioning in most daily social and interpersonal functioning. Needs supervised residential care. Unable to form or sustain long-term relationships.
80	Completely unable to perform daily activities, requiring total dependence on another person. Impairment levels preclude all useful functioning. Unable to function within society.

Notes to Table 12.4

1. Supervision means the immediate presence of a suitable person, responsible in whole or in part for the care of the employee

2. Suitable person means a person capable of responsibly caring for the employee in an appropriate way

12.5 Cranial Nerves

Unless otherwise indicated, only the highest WPI rating from the preceding four categories (that is all tables in sections 12.1, 12.2, 12.3 and 12.4) may be combined with a WPI rating from one or more tables in the remainder of Chapter 12, and with WPI ratings from other Chapters. (For further information about deriving WPI ratings from an assessment of cerebral function, see Steps 1 to 5 in the Introduction to Chapter 12).

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12.5.1 The Olfactory Nerve (I)

The WPI ratings in Table 12.5.1 reflect bilateral partial loss of function and total loss of function (anosmia).

A WPI rating made under Table 12.5.1 may not be combined with a WPI rating for the same condition made under Table 7.3: Olfaction and Taste (Chapter 7 - Ear, Nose and Throat Disorders).

Table 12.5.1: The Olfactory Nerve (I)

% WPI	Criteria
2	Bilateral partial loss of function.
5	Bilateral total loss of function.

12.5.2 The Optic Nerve, the Oculomotor and Trochlear Nerves and the Abducens (II, III, IV and VI)

Dysfunction of these cranial nerves causes impairment of the visual system and is to be assessed under Chapter 6 - The Visual System.

12.5.3 The Trigeminal Nerve (V)

This is a mixed nerve having sensory fibres to the face, cornea, anterior scalp, nasal and oral cavities, tongue and supratentorial dura mater. It also transmits motor impulses to the muscles of mastication.

Where sensory loss affects more than one division of the nerve with differing severity, the respective values for each affected division may be combined using the Combined Values Chart (see Appendix 1).

If paralysis of the motor fibres of the nerve causes interference with speech, this impairment should be evaluated in accordance with the criteria in Chapter 7 - Ear, Nose and Throat Disorders.

Impairment due to chewing and swallowing difficulties is assessed under Table 12.5.6: The Glossopharyngeal, Vagus, Spinal Accessory and Hypoglossal Nerves. For the same condition, WPI ratings derived from Table 12.5.6 may not be combined with WPI ratings from Table 7.7: Chewing and Swallowing (Chapter 7 - Ear, Nose and Throat Disorders).

Table 12.5.3: The Trigeminal Nerve (V)

% WPI	Criteria
0	No loss of sensory function.
3	Partial loss of sensory function of any one division of the nerve.
6	Partial loss of sensory function of any two divisions of the nerve.
7	Complete loss of sensory function of any one division of the nerve; and/or Mild uncontrolled facial neuralgic pain that may interfere with Activities of Daily Living.
9	Partial loss of sensory function of all three divisions of the nerve.
14	Complete loss of sensory function of any two divisions of the nerve; and/or Moderately severe, uncontrolled facial neuralgic pain that interferes with Activities of Daily Living.
20	Complete loss of sensory function of all three divisions of the nerve; and/or Severe, uncontrolled, unilateral or bilateral facial neuralgic pain preventing performance of Activities of Daily Living.

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12.5.4 The Facial Nerve (VII)

This is a mixed nerve. The motor part innervates the facial muscles of expression and the accessory muscles for chewing and swallowing. The sensory fibres carry tactile sensations from the ear, soft palate and adjacent pharynx, and transmit taste from the anterior two thirds of the tongue.

Facial nerve injury, complicated by visual changes, such as occur with corneal desiccation and scarring, should rate as a significant impairment. This should be assessed under Chapter 6 - The Visual System, and may be combined with a WPI rating from Table 12.5.4.

For the same condition, a WPI rating from Table 12.5.4 may not be combined with a WPI rating from Table 7.3: Olfaction and Taste (Chapter 7 - Ear, Nose and Throat Disorders).

Table 12.5.4: The Facial Nerve (VII)

% WPI	Criteria
3	Complete loss of taste over anterior two thirds of tongue; or Mild unilateral facial weakness.
12	Mild bilateral facial weakness; or Severe unilateral facial paralysis with 75% or greater facial involvement and with inability to control eyelid closure.
30	Severe bilateral facial paralysis with 75% or greater facial involvement and with inability to control eyelid closure.

12.5.5 The Auditory Nerve (VIII)

The Auditory Nerve has two portions:

the cochlear portion concerned with hearing; and
the vestibular portion concerned with balance and spatial orientation.

Impairment of hearing due to a lesion of the cochlear portion of the nerve should be evaluated under Chapter 7 - Ear, Nose and Throat Disorders. A WPI rating derived from Chapter 7 may be combined with a WPI rating from Table 12.5.5.

Lesions of the vestibular portion of the nerve result in vertigo with or without nausea and vomiting.

Table 12.5.5 is used where symptoms are continuous.

To obtain the final WPI rating in the case of episodic disturbances of equilibrium (such as Meniere's disease), apply the modifier from Figure 12-C to the WPI rating from Table 12.5.5.

Table 12.5.5: The Auditory Nerve (VIII)

% WPI	Criteria
0	Symptoms of vestibular dysequilibrium present without supporting objective findings, and Activities of Daily Living can be performed without assistance.
5	Symptoms of vestibular dysequilibrium present with supporting objective findings, and most Activities of Daily Living can be performed without assistance.
10	Symptoms of vestibular dysequilibrium present with supporting objective findings, and most Activities of Daily Living, except those of a complex nature (for example, riding a bicycle), or hazardous nature (for example, walking on a roof, girders or scaffolding), can be performed without assistance.
20	Symptoms of vestibular dysequilibrium present with supporting objective findings, and assistance is required with most Activities of Daily Living, except self care, walking, and riding in a motor vehicle as a passenger.
30	Symptoms of vestibular dysequilibrium present with supporting objective findings, and assistance is required with all Activities of Daily Living, except self care.
45	Symptoms of vestibular dysequilibrium present with supporting objective findings, and assistance is required with all Activities of Daily Living, including self care not requiring ambulation.
60	Symptoms of vestibular dysequilibrium present with supporting objective findings, and Activities of Daily Living cannot be performed without assistance, including self care.
80	Symptoms of vestibular dysequilibrium present with supporting objective findings, and Activities of Daily Living cannot be performed without assistance, including self care, and home confinement is necessary

Notes to Table 12.5.5

1. Assistance means the immediate presence of a suitable person, responsible in whole or in part for the care of the employee

2. Suitable person means a person capable of responsibly caring for the employee in an appropriate way

Figure 12-C: % WPI Modifiers for Episodic Conditions

Signs and Symptoms	Modifier
Absent.	0.0
Intermittent.	0.2
Present on a daily basis for periods aggregating 3 or more months per year but less than 6 months per year.	0.4
Present on a daily basis for periods aggregating 6 or more months per year but less than 8 months per year.	0.6
Present on a daily basis for periods aggregating 8 months or more per year but less than 10 months per year.	0.8
Present on a daily basis for period aggregating 10 months per year or more.	1.0

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12.5.6 The Glossopharyngeal, Vagus, Spinal Accessory and Hypoglossal Nerves (IX, X, XI and XII)

The spinal accessory nerve assists the vagus nerve in supplying some of the muscles of the larynx, and innervates the cervical portions of the sternocleidomastoid and trapezius muscles.

Disorders of these nerves affecting musculoskeletal function should be assessed in accordance with criteria contained in Chapter 9 - Musculoskeletal System.

The glossopharyngeal nerve and the vagus nerve are mixed nerves supplying sensory fibres to the posterior third of the tongue, larynx and trachea. Sensory impairment may contribute to difficulties swallowing, breathing and speaking.

The hypoglossal nerve is a motor nerve that innervates the musculature of the tongue.

Dysarthia is a situation where the articulation of the voice mechanism is at fault. Pronunciation is unclear, although the linguistic content and meaning are normal.

Dysphagia is a condition in which the action of swallowing is difficult to perform, painful, or in which swallowed material is held up in its passage to the stomach. Speech is slowed or slurred and may be completely unintelligible or non-functional. All other causes of difficulty with chewing or swallowing should be assessed using Table 7.7: Chewing and Swallowing, (Chapter 7 - Ear, Nose and Throat Disorders). For the same condition, WPI ratings from Table 7.7 may not be combined with WPI ratings from Table 12.5.6.

Table 12.5.6: The Glossopharyngeal, Vagus, Spinal Accessory and Hypoglossal Nerves (IX, X, XI and XII)

% WPI	Criteria (ONE required - different conditions may be assessed separately)
10	Mild dysarthria (speech slow or slurred especially when tired). Dystonia (only neurological). Mild dysphagia (coughing on liquids or semi-solid foods). Diet limited to semi-solid or soft foods. Spasmodic torticollis (only neurological).
25	Moderately severe dysarthia (speech is laboured, imprecise, and often unintelligible). Speaker is required to repeat often and may need augmentative device to help convey message. Moderately severe dysphagia with nasal regurgitation and aspiration of liquids and semisolid foods. Diet limited to liquid foods.
50	Severe dysarthia - speech may be completely unintelligible or non-functional, or intelligible only to familiar people, and only with the aid of an augmentative communication device. Severe dysphagia (inability to swallow food, liquids or manage oral secretions). Regular suctioning required. Ingestion of food requires tube feeding or gastrotomy.

12.6 Neurological Impairment of the Respiratory System

Where the ability to breathe is impaired because of a neurological impairment, Table 12.6 below may be used. Impairments of the respiratory system not of documented neurological origin are assessed under Chapter 2 - The Respiratory System. They are not assessed under Table 12.6.

Table 12.6: Neurological Impairment of the Respiratory System

% WPI	Criteria
10	Able to breathe spontaneously but has difficulty performing Activities of Daily Living that require exertion.
25	Able to breathe spontaneously but is restricted to sitting, standing or limited walking.
60	Able to breathe spontaneously but to such a limited degree that he or she is confined to bed.
90	No capacity for spontaneous respiration.

12.7 Neurological Impairment of the Urinary System

Where there is loss of bladder control due to a neurological impairment, Table 12.7 may be used.

Impairments of the urinary system not of documented neurological origin are assessed under Chapter 10 - Urinary System. They are not assessed under Table12.7.

Documentation by cystometric and other relevant urologic tests may be necessary.

The status of the upper urinary tract must also be considered. Except for an impairment of bladder function, if several impairments of the urinary system are present, a WPI rating from Table 12.7 may be combined with a WPI rating from Chapter 10 - Urinary System.

Table 12.7: Neurological Impairment of the Urinary System

% WPI	Criteria
5	Some degree of voluntary control but impaired by urgency or intermittent incontinence.
15	Good bladder reflex activity, limited capacity, and intermittent emptying without voluntary control.
30	Poor bladder reflex activity, intermittent dribbling, and no voluntary control.
50	No reflex or voluntary control of the bladder.

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12.8 Neurological Impairment of the Anorectal System

Where there is loss of ability to control emptying because of a neurological impairment, Table 12.8 below may be used. Impairments of the anorectal system not of documented neurological origin are assessed under Chapter 8 - The Digestive System. They are not assessed under Table 12.8.

Table 12.8: Neurological Impairment of the Anorectal System

% WPI	Criteria
10	Reflex regulation but only limited voluntary control.
20	Reflex regulation but no voluntary control.
40	No reflex regulation or voluntary control.

12.9 Neurological Impairment Affecting Sexual Function

Where there is loss of awareness and the capability of having an orgasm because of a neurological impairment, Table 12.9 below may be used. Impairments of sexual function not of documented neurological origin are not assessed under Table 12.9. They are assessed under Chapter 11 - The Reproductive System.

The employee's previous sexual functioning should be considered.

Impairment of the peripheral nervous system is assessed using the methodology for assessing the lower and upper extremities described in Chapter 9 - The Musculoskeletal System.

Table 12.9: Neurological Impairment Affecting Sexual Function

% WPI	Criteria
10	Sexual functioning is possible, but with difficulty of erection or ejaculation in men, or lack of awareness, excitement or lubrication in either sex.
15	Reflex sexual functioning is possible, but there is no awareness.
20	No sexual functioning.